Essentials in Dermatology
(with Multiple Choice Questions)
Essentials in Dermatology
(with Multiple Choice Questions)
Devinder M Thappa MD, DHA, MNAMS, FIMSA
Professor and Head
Department of Dermatology and STD
Jawaharlal Institute of Postgraduate Medical Education and Research
JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD
New Delhi • Ahmedabad • Bengaluru • Chennai • Hyderabad • Kochi
Kolkata • Lucknow • Mumbai • Nagpur • St Louis (USA)
The second edition of Essentials in Dermatology (with Multiple Choice Questions) is being published
6 years after the appearance of the first edition. The encouraging response to the first edition prompted
me to revise the book, keeping in view the comments received, and changing trends in the field of
This new edition incorporates differential diagnosis for each entity or group of entities to further
understand the subject critically. Three new chapters—Skin in Systemic Diseases, Skin Changes of
Pregnancy and Old Age, and Antiretroviral Therapy (ART) have been added. The existing chapters
have been updated and treatment guidelines revised. Newer entities have been included under
various chapters, but not at the cost of brevity and conciseness. For better understanding of the text,
better photographs and clinical illustrations have been incorporated.
The section on multiple choice questions has been considerably expanded, and this section has
been divided into two—for PG entrance examinations and for postgraduates in dermatology.
Additional mnemonics have been included in the useful medical mnemonics section.
The objective of this edition remains the same—to serve as an aid for beginners in dermatology
and those aspiring for PG entrance examinations.
The making of the revised edition of this book involved a number of people besides myself.
Many of the chapters were revised with inputs from my senior residents Dr Rashmi Kumari,
Dr Amiya Kumar Nath and Dr Abarna Devi and junior residents Dr Nidhi Singh, Dr Abhijit
Chougule, Dr Kishan Kumar Agarwal, Dr Balaji Adityan, Dr Sowmya Kaimal and Dr Sakthi Kandan.
The photographs utilized in the book have been possible due to the Medical Illustration Department
of the hospital, and the digital cameras of my postgraduates, making the new edition a colorful
experience. My laboratory technician Mr Samsudeen deserves a mention for his skill in the staining
and preparation of laboratory material for photomicrography. The final making of this edition has
involved the support and cooperation of all my esteemed colleagues, patients and the forgotten
names of residents (who worked for the first edition of the book).
As always, this edition is open to constructive criticism and suggestions for its further
Devinder M Thappa
Preface to the Second Edition
Dermatology, the science of the skin, was one of the many specialties, which evolved from general
internal medicine during the course of the nineteenth century. In India, recognition of dermatology
as a specialty distinct from internal medicine is recent; it has still not grown to its full stature in
practice and teaching. In spite of having some share in the curriculum, dermatology remains a
neglected subject because of its non-inclusion in the qualifying examination at MBBS level. There
has been an explosion of knowledge—easily documented by the size of standard dermatology
textbooks, whose length has increased from an average of 1000 pages to the most recent editions of
Fitzpatrick and of Rook, which are more than 3000 and 3600 pages, respectively. Expansion has
been greater on the surgical and cosmetic side of the specialty, which barely existed 50 years ago.
Such vast knowledge is difficult to grasp in 3 years course of MD dermatology, venereology and
leprology, sometimes may be at the cost of another. So there was need for a short textbook for
postgraduates who have just joined the specialty to have the glimpse of the subject and understand
the basic dermatology before venturing for detailed standard textbooks. There is lack of simple but
up to date book for undergraduates who are preparing for Postgraduate Entrance Examination.
Though market is flooded with a number of books, many of them are not even framed by dermatology
specialty individuals and lack correct and appropriate information. This prompted me to write this
book to fulfill the needs of students aspiring for entering in postgraduate courses in reputed institutes
of India. The material in this book is based on the standard textbooks and latest information from
specialty journals. Introduction to MCQs is a unique section in this book to guide the students. The
multiple choice questions are taken from a number of sources to sensitize the student to know
certain subject areas in this specialty thoroughly and accordingly the book section gives relevant
points highlighted for quick revision of facts. The suggestions and healthy critical remarks will be
very much appreciated to improve this book.
Devinder M Thappa
Preface to the First Edition
I would like to thank those who helped me to update chapters
1. Dr Balaji Adityan for updating
• Principles of Diagnosis in Dermatology
• Bacterial Infections
• Viral Infections
• Fungal Infections
• Skin Changes in Pregnancy and Old Age
2. Dr Sakthi Kandan for
• Disorders of Hair and Nails
• Metabolic and Nutritional Disorders
• Skin in Systemic Diseases
3. Dr Sowmya Kaimal for
• Pediatric Dermatology
• Human Immunodeficiency Virus Infection (HIV) and Acquired Immunodeficiency Syndrome
4. Dr Amiya Kumar Nath for
• Connective Tissue Disorders
• Genetics and Genodermatoses
5. Dr Abhijit Chougule for
• Differential Diagnosis for Leprosy
• Treatment of Leprosy
6. Dr Kishan Kumar Agarwal for
• Urticaria, Angioedema and Pruritus
• Disorders of Sebaceous, Eccrine and Apocrine Glands
7. Dr Nidhi Singh for
• Cutaneous Tuberculosis and Atypical Mycobacterial Infections
• Vesiculobullous Disorders
• Pigmentary Disorders
Following residents helped in framing MCQs for postgraduates
1. Dermatology Basics
• Dr Abhijit Chougule
• Dr Kishan Kumar Agarwal
2. Clinical Dermatology Part -I
• Dr Rashmi Kumari
Essentials in Dermatologyx
• Dr Balaji Adityan
• Dr Ajay Kumar Singh
• Dr Anuradha Priyadarshini
• Dr Tukaram Sori
3. Clinical Dermatology Part -II
• Dr Malathi
• Dr Sathyamoorthy
4. Sexually Transmitted Diseases
• Dr Sowmya Kaimal
• Dr Rajalakshmi
• Dr Abarna Devi
• Dr Sakthi Kandan
“…Most of the dermatology textbooks are too much voluminous for undergraduate students already
overburdened with other heavy weight subjects. Not only undergraduates, beginners at the
postgraduate level also face problem to acquire basic conception from such large books. So there is
always a need for a concise book which can provide clear basic conception and up-to-date knowledge
to the students….will be of immense help to the postgraduate entrance examinees….should be
collected in all undergraduate medical college libraries for the benefit of the students…”
Indian J Dermatol 2003; 48(4): 248.
“…The stated aim of the book is to have a short textbook for new entrants to postgraduate
studies in dermatology which could glimpse of the subject and understand basic dermatology before
venturing for detailed standard textbooks. The second aim stated is to fulfill the needs of students
aspiring for entering in postgraduate courses in reputed institutes….well written and fulfill the
stated aims…An approach to attempting MCQs appears to be a very useful chapter….strongly
recommend this book to the new entrants in specialty training and those preparing for admission to
Indian J Dermatol Venereol Leprol 2004; 70(6): 393.
SECTION 1: DERMATOLOGY
1. Ten Most Influential People in Medicine and Dermatology .................................................... 3
2. History of Dermatology in the World ............................................................................................ 5
3. Microanatomy of the Skin................................................................................................................ 8
4. Physiology, Biochemistry and Immunology of the Skin ......................................................... 13
5. Principles of Diagnosis in Dermatology ..................................................................................... 16
6. Bacterial Infections .......................................................................................................................... 31
7. Viral Infections ................................................................................................................................. 43
8. Fungal Infections ............................................................................................................................. 57
9. Infestations ........................................................................................................................................ 72
10. Papulosquamous Disorders ........................................................................................................... 82
11. Eczema................................................................................................................................................ 99
12. Vesiculobullous Disorders........................................................................................................... 114
13. Cutaneous Tuberculosis and Atypical Mycobacterial Infections ........................................ 127
14. Connective Tissue Disorders (Collagen Vascular Disorders) ............................................... 134
15. Pigmentary Disorders ................................................................................................................... 148
16. Keratinization Disorders .............................................................................................................. 156
17. Urticaria, Angioedema and Pruritus .......................................................................................... 166
18. Drug Eruptions, Erythema Multiforme, Stevens-Johnson Syndrome
and Toxic Epidermal Necrolysis ................................................................................................. 172
19. Disorders of Sebaceous, Eccrine and Apocrine Glands ......................................................... 180
20. Disorders of Hair and Nails ......................................................................................................... 189
21. Metabolic and Nutritional Disorders......................................................................................... 198
22. Genetics and Genodermatoses .................................................................................................... 210
23. Skin in Systemic Diseases............................................................................................................ 222
Essentials in Dermatologyxiv
24. Skin Changes of Pregnancy and Old Age ................................................................................. 237
25. Pediatric Dermatology .................................................................................................................. 240
26. Benign, Pre-malignant and Malignant Tumors of the Skin .................................................. 246
27. Topical Formulary and Key Systemic Drugs............................................................................ 257
28. Dermatosurgical Procedures ........................................................................................................ 272
SECTION 2: SEXUALLY TRANSMITTED DISEASES AND HIV INFECTION
29. Historical Milestones in Sexually Transmitted Diseases ...................................................... 279
30. History Taking and Examination in Sexually Transmitted Diseases (STDs).................... 282
31. Sexually Transmitted Diseases ................................................................................................... 288
32. Human Immunodeficiency Virus Infection (HIV) and Acquired
Immunodeficiency Syndrome (AIDS) ....................................................................................... 309
33. Antiretroviral Therapy (ART) ..................................................................................................... 318
SECTION 3: LEPROSY
34. Historical Milestones in Leprosy ................................................................................................ 327
35. History Taking and Examination in Leprosy ........................................................................... 330
36. Clinical Leprosy ............................................................................................................................. 333
Multiple Choice Questions.................................................................................................................... 351
Some Useful Medical Mnemonics ....................................................................................................... 441
Terminology ............................................................................................................................................. 447
Answers ..................................................................................................................................................... 465
Index ........................................................................................................................................................... 469
Ten Most Influential People in Medicine and Dermatology 3
THE MILLENNIUM AND MEDICINE:
THE TEN MOST INFLUENTIAL
1. Louis Pasteur (1822-1895): Proposed the
“germ theory”. He first associated a specific
micro organism (bacillus) with a specific disease
(anthrax). He developed the method of
pasteurization—a heating process that kills
bacteria in milk, wine and other liquids. He was
also a pioneer in stereochemistry.
2. Robert Koch (1843-1910): The first to isolate
the anthrax bacillus (1876). In 1883, he published
a method of preventive inoculation against this
disease. In 1882, he announced the discovery of
tubercle bacillus and in 1883; he discovered the
cause of cholera. He was awarded the nobel prize
in physiology or medicine in 1905.
3. Rudolf Virchow (1821-1902): Founded
Cellular pathology. His concept that the basis
of disease is the cell, the essential functional and
structural unit of the body, was of monumental
importance as a basis for understanding the
cause, the process and the results of the disease.
4. Gregor Mendel (1822-1844): Formulated the
laws of heredity. Mendel’s work laid the
mathematical foundation of the science of
1 Ten Most Influential People in
Medicine and Dermatology
5. Francis Crick (1916-) and James Watson
(1928): Accredited with determining the
molecular structure of DNA, the chemical
substrate of heredity, which is regarded as the
most important discovery of the 20th century in
medicine and science. They were awarded the
nobel prize in 1962 sharing it with Maurice
Wilkins (1916). Currently, Crick is associated
with the Salk Institute for biological studies in
San Diego while Watson is the director of the
Cold Spring Harbor lab in southeastern New
6. Marie Curie (1867-1934): Discovered
radioactivity and was given the nobel prize in
1903. The discovery formed the basis of radiation
therapy. In 1911, she was again conferred the
Nobel Prize in chemistry for her discovery of
radium and polonium.
7. Edward Jenner (1749-1823): Introduced the
inoculation for smallpox at the end of the 18th
century, which is considered one of the greatest
triumphs in the history of medicine.
8. Karl Landsteiner (1868-1943): Called the
“father of blood grouping” - a concept without
which blood transfusion would not be possible.
In 1901, he showed that there are at least three
major types of blood. Landsteiner was awarded
the noble prize for his work in 1930.
Essentials in Dermatology4
9. Wilhelm Rontgen (1845-1923): Discoverer of
X-rays in 1895 and nobel prize winner in Physics
in 1901. The value of X-rays in the diagnosis and
treatment was recognised and accepted almost
from the outset of their discovery.
10. Sigmund Freud (1856-1939): Considered the
founder of psychoanalysis, he believed that a
complex of repressed and forgotten expressions
underlies all abnormal mental states and that
infantile mental processes are important in later
TEN MOST INFLUENTIAL PERSONS IN
DERMATOLOGY, VENEREOLOGY AND
1. Dr. JS Pasricha: Pioneer of pulse therapy in
pemphigus, contact dermatitis in India.
2. Dr. LK Bhutani: Clinical dermatology,
“Bhutani’s Colour Atlas of Dermatology”,
3. Dr. Dharmendra: “Father of leprosy” in India.
4. Dr. RV Rajam and Dr. PN Rangaiah:
Monograph on donovanosis.
5. Dr. VN Sehgal: For his literary contribution
in dermatology, venereology and leprosy.
6. Dr. Patrick Yesudian: Clinician par excellence,
known for “Patrick Yesudian sign” for palmar
freckling in neurofibromatosis type 1.
7. Dr. KC Kandhari: Established department of
dermatology at AIIMS.
8. Dr. Gurmohan Singh: contribution to Indian
and community dermatology.
9. Dr. Surinder Kaur: Established department
of dermatology at PGIMER, Chandigarh.
10. Dr. Sardarilal: First editor of Indian Journal
of sexually transmitted diseases, and for
contributions in donovanosis.
TEN MOST INFLUENTIAL PERSONS IN
DERMATOLOGY, VENEREOLOGY AND
1. Dr. Ferdinand Ritter von Hebra– Founder of
the new Vienna school of dermatology, which
set the basis for modern dermatology.
2. Dr. Robert Willan– Founder of dermatology
as a medical specialty.
3. Dr. Josef Jadassohn– Best remembered for his
handbook of skin and venereal disease
(41 volumes), pioneer in allergology, introduced
4. Dr. Johnathan Hunter– Natural history of
syphilis, role of inflammation in healing.
5. Dr. Paul Ehrlich– Developed salvarsan (magic
bullet) as a treatment for syphilis, was the first
to stain tubercle bacilli.
6. Dr. Thomas Bernard Fitzpatrick– Proved that
melanin was produced in melanosomes, first
editor of Dermatology in General Medicine
7. Dr. Arthur Rook (1918-1991), Dr. Darrell
Sheldon Wilkinson and zoologist John Ebling
(1918-1992): Produced their major work,
Textbook of Dermatology (alias The Rook Book)
8. Dr. Paul Gerson Unna, Dr. HKB Pinkus, Dr.
A Bernard Ackerman, and Walter F. Lever:
Contributions to dermatopathology.
9. Heinrich Koebner– Koebner phenomenon,
founder of the dermatology clinic at the
University of Breslau.
10. GHA Hansen– Identified M. leprae as the
causative agent of leprosy in 1873.
History of Dermatology in the World 5
HISTORY OF DERMATOLOGY IN THE
• In Greek and Roman era, Hippocrates
recognized and described many diseases.
Some of the medical facts he observed are as
true today as they were over 2000 years ago.
He rescued medicine from magic and
superstition, therefore rightly so called “the
Father of Medicine”.
• Dermatology, the science of the skin, was
one of the many specialties, which evolved
from general internal medicine during the
course of the nineteenth century. Most
diseases of skin, as ‘external diseases’, had
for many centuries fallen within the province
of the surgeon or of the quack.
• Until the eighteenth century was well-
advanced, physicians with few exceptions
were little concerned with the skin, apart
from the exanthematic eruptions of acute
fevers. However, during the last decades of
that century, many of the great physicians
recorded their observations on diseases of the
skin. The solid contributions of some, such
as Heberden and Cullen, which have
received too little attention from the
historians of dermatology, laid the
foundations on which the pioneer specialist
2 History of Dermatology
in the World
dermatologists of the following century were
able to build.
• Despite developments in 19th century-
vaccination against small pox, recognition
of cellular pathology, Louis Pasteur’s germ
theory of infection, development of
anaesthesia and microscope, the treatment
of most skin diseases was at best
symptomatic and at worst dangerous.
• Amongst the first to specialize in
dermatology was Ferdinand Hebra (1816-
1880) in Vienna, who led the torch of
dermatology, others followed him. The last
half of 19th century saw dermatology and
venereology emerge as a specialty in its own
• The 20th century brought a wealth of new
scientific knowledge that can be used to help
the sick. Perhaps, the most important single
discovery was that of Sir Alexander
Fleming, the British bacteriologist who
found the first antibiotic, penicillin.
• During 20th century, certain turning points
occurred in general sociocultural factors
(welfare—public health, vaccines, hygiene,
clean water, sewerage, etc; war; communi-
cations–books, photography, radio, films,
television, computers; transport), general
scientific developments (genetics- structure
Essentials in Dermatology6
of DNA; inflammation-histamine, prostag-
landins, cytokines, adhesion molecules;
immunology-cell mediated and humoral
immunity; tissue culture; pathogenic agents-
spirochetes, viruses, prion; therapies- x-rays,
antibacterial, immunosuppressive; con-
trolled clinical trials), and strictly
dermatological areas(books- Jadassohn,
Pillsbury, Rothman, Rook; biology-
keratinocyte, melanocyte, Langerhans cell,
basement membrane; diseases- epidermo-
lysis bullosa, pemphigus, toxic epidermal
necrolysis; people- from Unna to Katz;
therapies- local steroids, griseofulvin,
phototherapy, retinoids, Moh’s surgery,
EVOLUTION OF DERMATOLOGY
• In India, recognition of dermatology as a
specialty distinct from internal medicine is
recent; it has still not grown to its full stature
in practice and teaching.
• Therapeutics of dermatoses have been
known and practiced by our ancient
physicians for centuries. Charaka Samhita
contains one chapter on the subject.
• Medical charlatans selling panaceas for
cutaneous ailments and faith healers were
commonly seen all over the country. With the
advent of scientific dermatology, their
number and importance has dwindled.
• In the latter part of the 19th century, the
health authorities in then British India
became aware of the need to have data on
prevalence of dermatoses and venereal
• The first chair of dermatology was
established at Grant Medical College,
Jamshedji Jeejebhoy Hospital (JJ Hospital),
Bombay in 1895.
• The second department, at the School of
Tropical Medicine in Calcutta, was started in
1923, after a gap of nearly 28 years, under
the patronage of Dr Ganpati Panja and
• During the period from 1956 to 1974, the
status of the specialty was further elevated
and steps were taken by state governments
to set up departments of dermatology and
venereology in medical institutions.
• Dr UB Narayan Rao, a pioneer in the
specialty, gets the credit for the creation of
an association of dermatologists and
venereologists in Bombay (July 1, 1947), and
for Indian Journal of Venereology started in
1935, renamed as Indian Journal of Venereal
Diseases and Dermatology in 1940, and later
renamed as Indian Journal of Dermatology
and Venereology in 1955, the first issue of
which was edited by him.
• In 1962, it was decided to affiliate the
association of dermatologists and
venereologists with Association of Physicians
of India (API).
• This continued until 1974, after which this
affiliation was severed and association
became an independent body.
• On January 28, 1973, the present association
the Indian Association of Dermatologists,
Venereologists and Leprologists (IADVL)
came into existence.
• Since 1976 the bimonthly journal is being
published under the title Indian journal of
dermatology, venereology and leprology.
EVOLUTION OF VENEREOLOGY
• Syphilis was first introduced into North India
nearly 500 years ago.
• National STD Control Programme was
started in 1946. This programme continued
to operate till 1991 and with the arrival of HIV
infection in the country, the programme was
History of Dermatology in the World 7
brought under the purview of National
AIDS Control Organization (NACO) in the
• The monograph by Rajam and Rangiah on
donovanosis (granuloma inguinale,
granuloma venereum) is testimony to the
teaching and research standards set by these
two giants at institute of venereology,
• Dr. CN Sowmini founded the Indian
Association for the study of sexually
transmitted diseases (IASSTD) in the year
• In the year 1980, this specialty, under the
banner of IASSTD, started its own exclusive
journal, the Indian Journal of Sexually
• The late Dr. Sardarilal was its founder editor
and guiding force, who had already made a
mark in the field of research, especially in
• Somehow venereology did not prosper as
much, even though it led in front of
dermatology and leprology in teaching and
in the starting of its own journal in early part
of 19th century.
• Unlike in the West, venereology in India has
been combined with dermatology in most of
EVOLUTION OF LEPROLOGY
• There is a great deal of speculation about the
early history of leprosy. The earliest records,
which give accurate descriptions of the
disease, come from India and may have been
written as early as 600 BC.
• In Sushrata Samhita (600 BC), one finds a
reasonably good account of the clinical
features and treatment of the disease.
Sushrata described the different forms of
leprosy, and these forms fit in fairly well with
the forms of the disease as recognized at the
• Sushrata described the treatment of the
disease with Chaulmoogra oil (hydnocarpus
oil), which till 1940s was the mainstay in the
treatment of the disease.
• The first known asylum for leprosy patients
was established in Calcutta early in the 19th
century, followed by another in Varanasi.
• “Leprosy in India”, a journal specific for
leprosy, was started by Dr. Ernest Muir in
1929, initially in the form of quarterly notes,
and later on transformed itself to a full-
fledged scientific journal. Consistent with its
contents and nature, Leprosy in India was
renamed as the Indian Journal of Leprosy in
• Dr. Dharmendra straddled the scene of
leprosy in India like a giant and is known for
lepromin test, Indian classification of types
of leprosy and the journal “Leprosy in India”.
• The National Leprosy Control Programme
(NLCP) was started in 1954-55. In view of
scientific advancement and availability of
highly effective treatment of leprosy, the
programme was redesignated as National
Leprosy Eradication Programme (NLEP) in
• In 1991, the World Health Organization set a
target of elimination of leprosy as a public
health problem by the year 2000. India
achieved this target in 2005.
Essentials in Dermatology8
Dermatology may be defined as the study of the
skin and its diseases or is a branch of medical
science, which deals with systematic study of
skin in health and disease. Since skin conditions
constitute 10 to 30% of outpatient attendance in
any hospital, they are often easily noticed by
others (hence a cause of great social concern to
the patient) and very often, skin diseases offer
diagnostic clue to many major systemic
disorders, makes this subject challenging and
important to study.
FUNCTIONS OF THE SKIN
The skin is the largest organ of the body,
accounting for 16-20% of total body weight. The
skin of an average adult covers an area just under
. It not only gives shape to the body but also
helps it in many ways – the important functions
of the skin are:
1. Protection (Barrier function) from:
a. Physical injuries
b. Chemical injuries
3. Sense organ: A number of sensations –
touch, pressure, warmth, cold and pain are
perceived by the skin.
4. Storage of electrolytes, carbohydrates,
water, fat, vitamins, proteins, etc.
3 Microanatomy of the Skin
5. Vitamin D formation: Vitamin D3 is
essential for skeletal development.
6. Absorption: The skin surface also performs
absorptive function and is the basis of
topical therapy in dermatology.
7. Excretion: Some of the toxins may be
excreted through the skin.
8. Immune surveillance: This immunological
function is performed by Langerhan’s cells,
dendritic cells (intermediate) and keratino-
9. Mechanical function: The mechanical
properties of the skin depend mainly on the
10. Cosmetic function: Colour of the skin and
hair and nails are important for their
decorative value. Hair does not perform a
“vital” physiologic function but it does
provide a sexually attractive ornament.
DEVELOPMENT OF SKIN
Epidermis develops from ectoderm lateral to
neural crest, dermis from mesenchyme and
neural crest cell, subcutaneous fat from
mesenchyme and melanocytes from neural crest.
Foetal skin development occurs in three stages-
specification, morphogenesis and differentiation.
Its specification occurs from 0 to 60 days,
morphogenesis from 2 to 5 months, and
differentiation from 5 to 9 months.
Microanatomy of the Skin 9
STRUCTURE OF THE SKIN
Skin has 3 layers (Fig. 3.1)
3. Subcutaneous fat (Hypodermis).
It is approximately 0.4 mm to 1.6 mm in
thickness. The majority of the cells in the
epidermis are the keratinocytes. These cells are
organized into five layers-stratum corneum,
stratum lucidum (present only in palmar and
plantar skin), stratum granulosum, stratum
spinosum, and stratum basale or stratum
germinatum (Fig. 3.2).
Stratum corneum is the outermost layer
containing flattened anucleated cells without cell
organelles. The thick epidermis of palms and
soles has an additional layer underneath the
stratum corneum that is electron lucent and is
called the stratum lucidum. The stratum
granulosum is so called due to the presence of
intracellular basophilic keratohyaline granules
and consists of 2-5 cells layer. The stratum
spinosum contains 8-10 layers of polyhedral cells
with round nuclei. The stratum basale or stratum
germinativum consists of single layer of cuboidal
or columnar cells.
Keratin filaments are a hallmark of the
keratinocytes and the process by which a
keratinocyte of the basal layer ultimately changes
into keratin is known as keratinization and it
usually takes 4 weeks for its completion. The
epidermal turnover time is about I month.
The other member cells found in the
epidermis are melanocytes (derived from neural
crest, produce melanin), Langerhans cells (origin
from bone marrow, play important role in
cutaneous immune mechanisms), and Merkel
cells (slow adapting type 1 mechanoreceptors).
The Dermal-epidermal Junction
The dermal-epidermal junction (DEJ) is a
basement membrane zone (BMZ) that welds the
epidermis to underlying dermis.
Fig. 3.1: Structure of the skin
Essentials in Dermatology10
Fig. 3.2: Diagrammatic representation of shapes of various cells in the epidermis and changes in them as
they move up from basal cell layer to stratum corneum during the process of keratinization
The dermal-epidermal junction is undulated,
forming dermal papillae (upward projections of
the dermis into the epidermis) and rete ridges
(downward projections of epidermis into the
dermis). The DEJ under electron microscope
consists of four components- plasma membrane
of basal keratinocytes with hemidesmosomes,
lamina lucida (made up of anchoring filaments
and laminin 5), lamina densa ( has type IV
collagen and laminin 5), and lamina
fibroreticularis (containing anchoring fibrils,
dermal microfibrils, and collagen fibers). This
DEJ is weakest at lamina lucida.
The dermis is formed by connective tissue
having fibres (collagen, elastic and reticulin) and
ground substance (made up of proteoglycans
and glycosaminoglycans). It varies in thickness
from about 1 mm on the face to 4 mm on the
back and thigh.
Collagen fibres are the major component of
the dermis, accounting for 75% of dry weight of
the skin. Approximately 80-90% of collagen
fibres in the dermis are of type I collagen. They
are responsible for the mechanical properties of
the dermis. Elastic fibers constitute approxi-
mately 4% of dry weight of dermal matrix
proteins. Due to their elasticity, they maintain
the normal configuration of the skin.
The dermis can be divided into an upper-
papillary dermis that interdigitates between the
rete ridges and the deeper-reticular dermis
recognized by the thicker, aggregated bundles
Microanatomy of the Skin 11
Epidermal Appendages Like
a. Pilosebaceous unit
b. Sweat glands.
Pilosebaceous unit: It consists of a hair follicle
containing hair and sebaceous glands opening
into follicular canal of hair follicle.
Sebaceous glands are lipid secreting
holocrine glands. Their maximum density is in
seborrhoeic areas of the body, i.e. scalp, face,
upper chest, etc. They get activated at puberty
under the influence of androgen hormone.
Functions of sebum are:
1. Barrier function by preventing loss of water
from the skin
2. Emulsification of surface eccrine sweat
3. May have mosquito repellant action
4. Protection against sunburn
5. Has a vitamin D precursor.
Hair structurally consists of a cuticle, cortex
and medulla. These keratinous fibres are of two
types in adults-terminal hair and vellus hair.
Hair grows at the rate of 0.3 mm per day and
they undergo growth cycle. These recurring
cycles consist of anagen (active growth phase),
catagen (static growth phase) and telogen
(shedding phase) phases. On the scalp, 80% to
85% of hair are in anagen phase and 15% to 20%
in catagen and telogen phase. The anagen phase
lasts for two to five years, a short catagen of few
days and a telogen phase of three months.
Functions of hair are:
2. Hair screens entry of irritants to nose
3. Protect scalp from sunrays
4. Shields the eyes
5. Helps in perception of tactile stimuli.
Sweat glands: Two types of sweat glands are
eccrine and apocrine sweat glands.
Eccrine sweat glands: They are tubular
structures, which open on to the skin directly and
have three segments–the secretory coil (consists
of single layer of secretory cells–clear and dark
cells) in the deep dermis, straight intradermal
(has two layers of cuboidal cells lined by
eosinophilic cuticle on luminal side) part and
coiled or spiral intraepidermal (consists of an
inner layer of luminal cells and two to three outer
layer of epithelial cells) part. Sweat glands are
most abundant on the palms, soles, forehead and
axillae. These glands are highly developed and
responsive part of the thermoregulatory
apparatus, innervated by cholinergic nerve
Functions of sweat are:
1. Sweating in heat stress
2. Excretion of heavy metals and drugs.
Apocrine sweat glands: These tubular glands
consists of two main parts – the coiled secretary
gland (consists of single layer of cuboidal or
columnar cells, surrounded by a layer of
myoepithelial cells) and the straight excretory
duct (consists of double layer of cuboidal cells
and inner eosinophilic cuticle) which opens into
follicular canal just above the openings of
sebaceous glands. They are distributed along the
mammary line, i.e. axillae, areolae, periumbilical
area, mons pubis, genital and perianal areas.
Apocrine gland secretion in man serves no
function. Pheromones–its role in humans is
Nail unit: It is yet another epidermal appendage.
It consists of nail matrix just underneath the
proximal nail fold which gives rise to nail plate
– a keratinized structure. The distal portion of
the nail matrix is visible usually in thumbnail as
white crescent or half moon known as lunula.
The rectangular nail plate rests on a nail bed and
is bounded on two sides by lateral nail folds.
The cuticle seals the space between nail folds and
nail plate. The distal portion of nail juts out as a
free end. The space underneath the free end of
the nail plate is called subunguium. In contrast
to hair, nail is a continuously growing structure,
usually at a rate of 0.1 mm per day.
Essentials in Dermatology12
Functions of nails are:
1. Protect terminal phalanges
2. Cosmetic function
3. Helps in appreciation of tactile stimuli
4. Scratching of skin
5. Helps in holding minute objects with finger
Besides the above elements, dermis contains
blood vessels which form two plexuses (other
than providing nutrition to the skin, blood
vessels regulate temperature and blood
pressure), lymphatics roughly parallel the major
vascular plexuses, nerves of the skin are part of
two major systems – somatic sensory and
autonomic motor, smooth muscle occurs in the
skin as arrectores pilorum, as the tunica dartos
of the scrotum and in the areolar around the
nipples and cells – mast cells, fibroblasts,
monocytes, macrophages, dendrocytes and
Subcutaneous Fat (Hypodermis)
The subcutaneous fat layer is constituted by
adipocytes. It is abundant over the breasts,
buttocks, and abdomen, thinner over the nose
and sternum and absent over the eyelids and
male genitalia. It acts as shock absorber, helps
in heat production and hormone conversion,
facilitate mobility of skin over structures that
underlie and acts as an insulator for heat. A
cosmetic role is contributed by the accentuated
distribution of fat in some sites in the sexes. Most
importantly, it stores triglycerides, which serves
as fuel for energy.
Physiology, Biochemistry and Immunology of the Skin 13
Main functions of the skin are protection,
thermoregulation, sensory, storage organ,
vitamin D formation, absorption, excretion,
immune surveillance, mechanical and cosmetic
function. Some important physiological,
biochemical, and immunological processes of the
skin are summarized below.
PROTECTIVE FUNCTIONS OF THE SKIN
The innermost region of human skin is the
subcutaneous fat layer. This layer insulates
reduces heat movement into or out of the body,
absorbs energy from blunt mechanical trauma
and is active in general energy metabolism.
Superficial to the fat layer lies the dermis,
composed of collgen-glycosaminoglycan
complexes which also protects the body from
blunt mechanical trauma. Overlying the dermis
is the epidermis which consists of several
stratifying layers of nucleated keratinocytes and
anucleated top layer, the stratum corneum which
performs the major barrier function.
The skin acts as a two way barrier to prevent
the inward or outward passage of water and
electrolytes. The physical barrier is largely
situated in the epidermis, isolated epidermis
being as impermeable as whole skin, whereas
once the epidermis is removed, the residual
dermis is almost completely permeable. The
4 Physiology, Biochemistry and
Immunology of the Skin
epidermal barrier is localized to the stratum
The skin has two barriers to UV radiations:
a melanin barrier in the epidermis; and a protein
barrier concentrated in the stratum corneum.
Both function by absorbing radiation thereby
minimizing absorption by DNA and other
The skin is considered to be a composite
membrane with three anatomically distinct
layers; the stratum corneum (10 µm), the viable
epidermis (100 µm), and the uppermost papillary
layer of the dermis (100-200 µm), each having a
different diffusion constant. Even healthy adult
human skin allows some permeation of almost
every substance, and rates of penetration of
different materials may differ by 10,000 fold.
The efficiency of the barrier differs between
body sites. The scrotum is particularly permeable
and the face, forehead, and dorsa of the hands
may be more permeable to water than the trunk,
arms, and legs. The palms are particularly
impermeable to nearly all molecules except
The barrier is affected by many other factors,
such as age, environmental conditions and
physical trauma, and permeability can be
Essentials in Dermatology14
enhanced by various agents, permitting
increased access of topically applied drugs.
Keratinization is a process of differentiation of
germinative cells in the basal cell layer into the
deceased cornified cells of stratum corneum.
1. Synthesis of distinctive proteins (e.g. keratins,
filaggrins, and involucrin) and lamellar
2. Alterations of nuclei, cytoplasmic organelles,
plasma membranes and desmosomes.
Keratin function is to provide mechanical
strength, cellular structure, and assistance in
adhesion molecule attachment. “Soft” keratin
desquamates as the result of enzymatic action
but the “hard” keratin of the hair and nails
does not, thus requiring periodic cutting.
The epidermis is the prototype of keratinizing
squamous epithelia, also present in the
oesophagus, vagina and oral mucosa.
MELANOCYTES AND MELANOGENESIS
Melanocytes are pigment forming cells in the
epidermis. Each melanocyte supplies pigment,
melanin to approximately 36 keratinocytes and
thus form epidermal melanin unit. Two types of
melanin are synthesized by melanocytes,
eumelanins and pheomelanins. Melanin is
synthesized from tyrosine under the influence
of enzyme tyrosinase through the formation of
various intermediates (dihydroxyphenylalanine
[dopa], dopaquinone, leucodopachrome,
dopachrome, 5’ 6’ dihydroxyindole, indole
5’ 6’-quinone, melanochrome).
FUNCTIONS OF THE MELANIN
1. Protect the skin from harmful effects of
sunlight by scattering and absorbing
2. Melanin may also act as a biochemical
neutralizer of toxic free radical oxygen
derivatives, byproducts of various inflam-
3. Melanocytes situated in the matrix of anagen
follicles impart to hair various colours, e.g.
blond, brunette and red head.
The maintenance of a near constant body core
temperature of 37o
C is a great advantage to
humans, allowing a constancy to biochemical
reactions which would otherwise fluctuate
widely with temperature changes.
The thermoreceptor cells of the skin are
distributed irregularly over the skin, there being
warm- and cold-sensitive thermoreceptors.
Information on changes in their stimulation in
response to changes in the temperature is sent
to the hypothalamus leading to either to
inhibition of sweating or stimulation of
shivering. Skin temperature has a greater role
in mediating the behavior, for example by
turning on the heating or putting on extra
Thermoregulation depends on several
factors, including metabolism and exercise but
the skin plays an important part in control
through the evaporation of sweat and by direct
heat loss from the surface. Heat can be lost
through the skin surface in four ways:
Skin failure is defined as a loss of normal
temperature control with inability to maintain
the core temperature, failure to prevent
percutaneous loss of fluids, electrolytes and
proteins with resulting imbalance and failure of
Physiology, Biochemistry and Immunology of the Skin 15
mechanical barrier to penetration of foreign
materials. Apart from thermal burns, skin failure
can occur as a consequence of a number of
dermatological diseases including Stevens
Johnson syndrome, toxic epidermal necrolysis,
pustular psoriasis and erythroderma of various
COLLAGEN IN THE DERMIS
The closely related proteins of collagen family
are the main fibrillary components of the
connective tissues and the major extracellular
proteins of the human body. The physiological
role of collagen fibers in the skin is to provide
tensile properties that allow the skin to serve as
a protective organ against external trauma.
Collagen is the major structural protein
constituting 70% to 80% of dry weight of the
dermis. The main aminoacids in collagen are
glycine, proline and hydroxyproline.
Elastic Fibers in the Dermis
Elastic fibers of the connective tissue form a
network responsible for the resilient properties
of the skin. In sun protected human skin, elastin
content is about 1% to 2% of the total dry weight
Ground Substance in the Dermis
The ground substance of skin is largely made
up of glycosaminoglycans(GAG) and provide
viscosity and hydration in the dermis. Three
types of GAG are chondroitin sulphate,
dermatan sulphate and hyaluronic acid.
IMMUNOLOGICAL COMPONENTS OF
The immunological functions of the skin depend
both upon cells in the epidermis and on dermal
cellular constituents. Antimicrobial peptides
(AMPs) are a diverse group of proteins that are
involved as first line of immune defense by many
living things. In human skin, AMPs provide a
chemical barrier to potentially pathogenic micro-
organisms. Sebaceous lipids have been reported
to possess antibacterial properties and
glycophospholipids and free fatty acids of
stratum corneum have bacteriostatic effect
selective for pathogenic organisms.
Skin associated lymphoid tissue (SALT) is
langerhans cells, T lymphocytes, mast cells and
keratinocytes. They are involved in various
hypersensitivity reactions of the skin. Hyper-
sensitivity is defined as inappropriate or
exaggerated immune response to a foreign or self
antigen resulting in tissue damage. Main types
of hypersensitivity responses of skin are type I
(immediate), type II (antibody-dependent
cytotoxicity), type III (immune complex disease)
and type IV(cell mediated or delayed). Urticaria
and anaphylaxis is the example for type I
hypersensitivity, transfusion reactions for type
II hypersensitivity, leukocytoclastic vasculitis for
type III hypersensitivity and allergic contact
dermatitis for type IV hypersensitivity.
Essentials in Dermatology16
Dermatologists often prefer to examine the
patient before obtaining the history and review
of systems. This approach is preferred because
diagnostic accuracy is higher when visual
examination is approached without precon-
ceived ideas. Moreover, some dermatologic
lesions are so distinctive that history is not
required to make a diagnosis.
A practical and convenient way to arrive at
a diagnosis may be...
PRELIMINARY GENERAL HISTORY
Biodata: Age, sex, income, occupation, address,
Principles of Diagnosis in
Chief complaints: Limit them to just three only
History of present illness: “What is your skin
This allows patient to point out the lesions and
the area involved.
Three basic questions.
1. Onset and evolution.
3. Treatment taken.
Onset and evolution: To determine the duration
of the disorder, how it evolved over time, initial
site of the disease, mode of spread.
Symptoms: Itching is the most common and
most important symptom in dermatology.
Intense itching, e.g. scabies, atopic dermatitis,
lichen planus, dermatitis herpetiformis.
Pain may predominate in herpes zoster,
furuncles, etc. Loss of sensation points towards
leprosy, or follicular mucinosis. Allodynia
(production of pain by trivial stimuli) occurs in
postherpetic neuralgia. Reversal of hot and cold
sensation may be due to ciguatera fish poisoning.
They may be just asymptomatic as in molluscum
contagiosum, basal cell carcinoma, etc.
Treatment history: Skin lesions are often self-
manipulated by home remedies, or over the
Principles of Diagnosis in Dermatology 17
counter medication, since they are easily
accessible, and since disease is of chronic nature.
Full detailed history of medication used
should be known because
1. Disease may be caused or aggravated by
medication- Fixed drug eruption, dermatitis
2. Patient may have already used the drug
without desired outcome, we planned to
give. Avoid potential embarrassment when
the patient says “I have already tried that and it
Detailed follow-up history: This history is taken
after some diagnosis or conclusion was reached
by initial history and examination, and this
• Past history.
• Family history.
• Review of systems.
• Social history.
• Females- menstrual/obstetric history.
a. History of same disease before.
b. History of prolonged illness– diabetes,
c. Drugs used for other problems (drug rash,
d. Drug allergies– avoid prescribing those
e. Atopic history– asthma, hay fever, eczema.
Family history: It is important for diagnosis,
prognosis, treatment and genetic counseling.
Family history important in:
a. Infectious disorders – scabies
b. Inherited disorders – atopy, psoriasis.
Review of other systems: It is required in
multisystem disorders like SLE, scleroderma, or
Social history: Encounter with potentially
sensitizing materials e.g., in patients with
industrial dermatosis, contact dermatitis. Stress
and strain at work may lead to exacerbation of
psoriasis, neurodermatitis, etc.
Habits: Alcohol induces porphyria cutanea tarda
in predisposed, influences the severity and
therapeutic options in psoriasis. Smoking may
be aggravating factor in palmoplantar
It has been said by Goethe “What is most difficult
of all? It is what appears most simple: To see with
your eyes what lies in front of your eyes” .
Requirements for the Skin to be
Three essential requirements
1. Preferably a completely undressed patient,
clothed only in an examination gown. If not
possible, at least, the affected part should be
2. Adequate illumination: Preferably sunlight
or a bright overhead fluorescent lighting.
Penlight is used in side lighting- to determine
if a lesion is subtly elevated and for
examining the oral cavity.
3. An examining physician ready to see what
is before him.
A complete cutaneous examination should
be made, this includes examining—
• Skin from head to foot.
• Mucous membrane in mouth and genitals
• Hair and nails.
The examination includes inspection and
palpation, besides percussion and auscultation.
Palpation is useful in—
• Assessing the texture and consistency.
• Evaluate whether a lesion is tender or not.
• Reassure a patient that they do not have a
Essentials in Dermatology18
Hand lens useful on occasions like identifying:
a. Altered skin markings in tumors.
b. Nail fold telangiectasia.
c. Burrows in scabies.
d. Wickham‘s striae- for this place a drop of
mineral oil on the area, which makes the
stratum corneum transparent.
Subtle genital warts- ‘aceto-whitening’,
gauze soaked with 5% acetic acid applied in
suspected area for 3 minutes, warts turn white.
Actually individual skin lesions are
analogous to the letters of the alphabet, and
groups of lesions can be analogous to words or
phrases. Basis of morphological lesions is given
in the form of table for clear understanding.
Basis of morphological lesions in dermatology
1. Impalpable change- Macule
2. Palpable change-
• Solid change-Papule, plaque, nodule, wheal
• Superficial visualized free fluid collection-
• Superficial free pus collection-Pustule, abscess
• Deep free fluid/semisolid material collection-Cyst
3. Loss of skin-Erosion, ulcer
4. Healing stage- Scale, crust
5. End stage- Atrophy, scar
Ultimately, diagnosis may rest on recognition
of lesions and their distribution and
arrangement, whether they are primary,
secondary or some special lesions. Describe their
shape, size, color and distribution. Take the
help of diagnostic tools for further details.
These are the lesions, which appear first in any
skin disease. They are the best clues to the
diagnosis. They are:
• Macule: The macule is a discrete, flat,
circumscribed lesion that differs from
surrounding skin because of its color
(Fig. 5.1). It may be a small or a large macule.
Earlier used term “patch” is now obsolete.
Macule may be erythematous, hypo-
pigmented, hyperpigmented or of any other
• Papule: It is a discrete, circumscribed, solid
elevated lesion of less than 0.5 cm in size (Figs
5.2 to 5.5). So, it is a palpable lesion. A papule
may be dome shaped, verrucous, umbi-
licated, pedunculated, etc.
Fig. 5.1: Macule—depigmented flat lesions of variable
size and shape of vitiligo vulgaris and lip tip type
Fig. 5.2: Papule—solid elevated lesions of verruca
vulgaris of less than 0.5 cm
Principles of Diagnosis in Dermatology 19
Fig. 5.3: Papule—dome shaped papule, a few of
them umbilicated of molluscum contagiosum
Fig. 5.4: Typical umbilicated papule of molluscum
Fig. 5.5 Violaceous colored papules of lichen
planus over the genitalia and thigh
• Plaque: A plaque is a circumscribed solid
raised lesion with a flat top. It is formed due
to coalescence of papules (Figs 5.6 and 5.7).
It may be a lichenified plaque, eczematous
plaque, psoriasiform plaque, flat smooth
• Nodule: A nodule is a discrete circumscribed
solid elevated lesion, which is more felt than
seen from the top (Figs 5.8 and 5.9). It may
develop from a papule.
terms used for circumscribed elevated lesions
containing free clear fluid, called blister. If it is
less than 0.5 cm, it is called vesicle (Fig. 5.10)
and if more than this, it is a bulla (Figs 5.11 and
5.12). They may be tense or flaccid.
Fig. 5.6: Plaque—flat elevated lesions covered with
silvery white micaceous scales of psoriasis vulgaris
Essentials in Dermatology20
Fig. 5.7: Large well-defined erythematous plaques
of psoriasis vulgaris
Fig. 5.8: Nodule—solid deep-seated elevated
lesion due to secondaries in the skin
Fig. 5.9: Erythematous tender nodules of furuncle
over the face and neck
Fig. 5.10: Vesicle—cluster of tiny blisters of herpes
labialis over the lips
Fig. 5.12: Large tense bulla of bullous pemphigoid
on an erythematous base
Fig. 5.11: Bulla—small blisters on erythematous
bases of bullous pemphigoid
Principles of Diagnosis in Dermatology 21
Fig. 5.13: Pustule—numerous tiny pus filled lesions
on erythematous background in a case of pustular
• Pustule: A pustule is a circumscribed
elevated lesion containing visible pus
(Fig. 5.13). It results from an epidermal or
upper dermal accumulation of pus.
• Cyst: A cyst is a sac that contains liquid or
• Wheal: Wheal is a pale or erythematous
edematous, transient, evanescent lesion.
• Diffuse thickening of skin: It may result
from edema of dermis (pitting edema or
nonpitting edema) or infiltration of dermis
(e.g. myxoedema, lepromatous leprosy).
Secondary or Consecutive Lesions
They are due to the subsequent changes, which
takes place on the primary lesions, either as a
part of natural evolution or due to manipulation
of the patient.
• Oozing: It is due to the rupture of vesicles or
• Crust: It is dried up exudate like serum, pus
or blood (Fig. 5.14). It may be thick or thin,
friable or adherent. It occurs in many
inflammatory and infectious diseases.
• Scale: Scales are thin, dry plates of heaped
up desquamating epithelial cells formed as
a result of either increased or abnormal
keratinization (Fig. 5.15).
• Excoriation: An excoriation is a superficial
erosion or ulcer caused by scratching. So,
it will be linear or have a geometric outline
• Erosion: It is a superficial ulceration
involving epidermis only which heals
without scarring (Fig. 5.17).
• Ulcer: It is a break in continuity of epithelium,
which involves epidermis, and dermis of the
skin (Fig. 5.18). It has length, breadth as well
as depth. It heals with scar formation.
• Fissure: Fissure is a linear crack in the skin,
which may be superficial or deep to the
• Lichenification: It is characterized by
thickening of the skin (becomes leather
like) with increased skin markings and
pigmentation. It is seen in chronic dermatitis.
• Scar: A scar is an evidence of destruction of
the skin with fibrotic tissue replacement. It
occurs wherever ulceration has taken place
and reflects the pattern of healing in those
Fig. 5.14: Crust—dried out oozed material over the
face in impetigo contagiosa
Essentials in Dermatology22
• Pigmentation: Pigmentation may be hyper,
hypo- or depigmentation of the skin (varies
according to the quantity of melanin).
• Atrophy: Atrophy refers to a diminution
in the size of a cell, tissue, organ or part of
the body. The skin becomes thin, shiny and
wrinkled. Atrophy may be of epidermal,
dermal or subcutaneous fat.
• Sclerosis: Sclerosis means a circumscribed or
diffuse hardening or induration in the skin.
It occurs as a result of an increase in the
amount of dermal collagen, expansion of the
Fig. 5.15: Scale—face and trunk covered with moist
scales of pemphigus foliaceous
Fig. 5.16: Excoriation—multiple linear scratch
marks due to itching over psoriatic plaques
Fig. 5.17: Erosion—multiple superficial eroded
areas in herpes genitalis
Fig. 5.18: Ulcer—single, painless, indurated
ulceration of extragenital primary chancre
Principles of Diagnosis in Dermatology 23
collagen by ground substance material or
altered quality of collagen.
These lesions are given below:
• Comedone: It is a plug of keratin and sebum
formed in the follicular canal of
pilosebaceous unit. Comedones may be
closed or open.
• Burrows: These are serpentine caves of
scabies mite at the level of stratum
granulosum. They are visible as S-shaped
brownish-black lesions, which at their distal
end have a papule housing the mite.
• Alopecia means loss of hair.
• Telangiectasia: It refers to individually
visible dilated vessels.
• Poikiloderma: It is a combination of atrophy,
pigmentation and telangiectasia.
• Purpura: It is visible extravasated blood
(Fig. 5.19). It may occur as tiny pinpoint spots
(petechiae) or larger spots (ecchymoses). The
term hematoma refers to an area of massive
bleeding into the skin and underlying tissues.
“Pinch purpura” hemorrhage induced by
mild often subclinical trauma is a charac-
teristic presentation of primary systemic
amyloidosis of the skin. Similar periorbital
hemorrhage following proctoscopy or
pulmonary function testing, postproctoscopic
purpura also typifies the vascular fragility
induced by systemic amyloidosis.
• Livedo: Blue red discoloration of the skin of
skin due to passive congestion of the vessels
often with net-like pattern
• Exanthem: Abrupt appearance of diffuse or
generalized similar skin lesions (usually
represents viral infections or drug reactions)
• Enanthem: Abrupt appearance of mucosal
lesions similar to exanthems.
• Nits: They are glistening white ovoid bodies
attached to shafts of hair.
Fig. 5.19: Purpura—multiple, small, erythematous non-blanchable lesions of purpura
Essentials in Dermatology24
Figs 5.20A and B: Distribution of skin lesions in
atopic dermatitis in infants
Figs 5.21A and B: Distribution of skin lesions in
atopic dermatitis in children and adults
DISTRIBUTION OF SKIN LESIONS IN SOME DERMATOLOGICAL DISORDERS
Disease Classical sites of involvement
1. Acne vulgaris Face, upper trunk, proximal parts of upper extremities
2. Atopic dermatitis Infants -face and extensor aspects of limbs (Figs 5.20A and B)
Children and adults-flexures (Figs 5.21A and B).
3. Dermatitis herpetiformis Scalp, extensor aspects of limbs, shoulder and buttocks (Figs
5.22A and B).
4. Lichen planus Flexor aspect of upper extremities (wrists), trunk (lumbosacral
area), shins, glans penis (Figs 5.23A and B).
5. Neurodermatitis Nape of neck, wrist, ankle, genitalia, and perianal area (Figs
5.24A and B).
6. Pityriasis rosea Herald patch-trunk. Daughter patches-Christmas tree pattern
over the trunk (Figs 5.25A and B).
7. Psoriasis vulgaris Extensor aspects of limbs, scalp, lumbosacral area (Figs 5.26A
8. Scabies Infants-Face, intertriginous area of fingers, palms and soles,
extensor aspect of limbs, around umbilicus, genitalia and
gluteal area (Figs 5.27A and B). Children and adults-finger
web spaces, wrist, elbows, axillary fold, around areola and
umbilicus, genitalia, and gluteal area (Figs 5.28A and B).
9. Seborrhoeic dermatitis Infants-Cradle cap over scalp (Figs 5.29A and B). Adolescence
and adults- scalp, eyebrows, nasolabial folds, presternal and
interscapular area, axilla and groin (Figs 5.30A and B).
10. Tinea versicolor Upper trunk (Figs 5.31A and B).
Principles of Diagnosis in Dermatology 25
Figs 5.22A and B: Distribution of skin lesions in
Figs 5.23A and B: Distribution of skin lesions in
Figs 5.24A and B: Distribution of skin lesions in
neurodermatitis (lichen simplex chronicus)
Figs 5.25A and B: Distribution of skin lesions in
Figs 5.26A and B: Distribution of skin lesions in
Figs 5.27A and B: Distribution of skin lesions in
infants in scabies
Essentials in Dermatology26
Figs 5.28A and B: Distribution of skin lesions in
children and adults in scabies
Figs 5.29A and B: Distribution of skin lesions in
seborrhoeic dermatitis in infants
Figs 5.30A and B: Distribution of skin lesions in
seborrhoeic dermatitis in adolescence and adults
Figs 5.31A and B: Distribution of skin lesions in
Certain phenomenon and signs are there to be
seen and observed; others need to be elicited by
• The Koebner phenomenon: The Koebner
phenomenon is the development of
morphologically identical lesion/s in the
traumatized uninvolved skin of patients who
have cutaneous diseases. It is also known as
isomorphic phenomenon, a self-explanatory
term. This phenomenon is observed in a number
of dermatological disorders such as psoriasis
(Fig. 5.32), lichen planus, vitiligo, eczema,
dermatitis herpetiformis, bullous pemphigoid,
warts (Figs. 33 and 34), molluscum contagiosum
(Fig. 5.35), etc.
• Reverse Koebner phenomenon: Area of
psoriasis clears of following injury.
• Remote reverse Koebner phenomenon is the
spontaneous repigmentation of vitiligo
patches distant from the autologous skin
Principles of Diagnosis in Dermatology 27
Fig. 5.32: Koebner phenomenon in psoriasis
vulgaris over the trunk
Fig. 5.33:Koebner phenomenon in
plane warts over the wrist
Fig. 5.34: Koebner phenomenon
in verruca vulgaris
Fig. 5.35: Koebner phenomenon in molluscum
• Dermographism: It can be elicited with the
help of blunt instrument like key. Firm
stroking of skin may result in exaggerated
triple response of Lewis, which persists for
more than 5 minutes. Stroking causes hista-
mine to be released, leading to localised
redness and edema (Wheal). Dermographism
can occur in urticaria.
• Darier’s sign: When the above phenomenon
is limited to skin overlying a lesion (macule
or papule), it is called as Darier’s sign and is
diagnostic of urticaria pigmentosa (Mast cell
• Pseudo-Darier’s sign: Here stroking of skin
produces transient induration with pilo-
Essentials in Dermatology28
erection, seen in congenital smooth muscle
• White dermographism: Stroking the skin of
atopic patients produces a characteristic
white line in the involved area.
• Grattage test: It is done on a scaly lesion to
look for types of scales. Scraping of the lesion
is done with a glass slide. Fine powdery
scales of tinea versicolor can be made out if
you examine the glass slide against light after
scraping the lesion.
• Candle sign and last cuticle sign: In
psoriasis, if the silvery-white scales are
scraped off, they detach from the lesions as
small flakes, similar to wax scraped from
candle. With continued scraping, one can
remove a coherent moist sheet from the lesion
corresponding to the lowest layers of
• Auspitz’s sign: This sign if present is
diagnostic of psoriasis. It has three
1. On scraping with glass slide, initially
silvery white micaceous scales come out.
2. Removal of the scales is followed by a thin
3. On its removal by glass slide, minute
pinpoint bleeding spots are seen.
• Diascopy (Vitropression): It is based on the
principle that vascular lesions will blanch in
response to pressure with a glass slide
whereas purpuric lesions, in which blood and
blood pigments have leaked from the
cutaneous vessels, will not blanch. Diascopy
is most useful in detection of nonblanchable-
raised purpura, the clinical hallmark of
cutaneous vasculitis. It is useful in
differentiating nevus anemicus from nevus
depigmentosus. Nevus anemicus (a localised
area of vasoconstriction) on diascopy of
adjacent skin reveals an identical color to
depigmented area. By contrast diascopy of
skin adjacent to nevus depigmentosus or
vitiligo, the affected area still remains paler.
Apple jelly nodules in lupus vulgaris active
edge of the lesion, appear as translucent
brownish color granulomatous nodules, a
distinctive feature of the disease.
• Ollendorf’s sign: If touching of the papule
of secondary syphilis with the head of pin is
exquisitely tender, then Ollendorf’s sign is
said to be present.
• Nikolsky’s sign: A frictional force is applied
with a finger or thumb over the apparently
normal skin, usually overlying a bone like the
clavicle or perilesional skin in a patient with
vesiculo-bullous lesions. If epidermis or
surface of the skin breaks down or peels off
leaving raw moist erosion, it is called positive
Nikolsky’s sign. Various disorders, in which
Nikolsky’s sign is positive, are pemphigus,
staphylococcal scalded skin syndrome, toxic
epidermal necrolysis, etc. This test is based
on the fact that in certain diseases, even the
normal looking skin has a weak cohesion
between its different layers.
• Bulla spread sign: It can be demonstrated by
marking the boundary of the bulla and then
applying pressure with a finger on the edge
of the bulla. In pemphigus, bulla spreads
beyond the marked line showing that active
process of acantholysis has weakened the
cohesion between keratinocytes.
• Button holing sign: In neurofibromatosis, if
fingertip is pressed over neurofibroma, the
finger gapes in due to defect in the dermis.
• Dimple sign: It distinguishes dermato-
fibroma from malignant melanoma.
Applying lateral pressure with thumb and
index finger –results in formation of a dimple
in dermatofibroma, whereas melanoma
protrudes above its original plane.
• Hess test or Capillary fragility test: A blood
pressure cuff is applied to upper arm
between systolic and diastolic pressure for
5 minutes. The number of petechiae in
predetermined area of 5 cm circle is counted.
Principles of Diagnosis in Dermatology 29
If number is more than 5, it is abnormal
• Pathergy test: Inject 0.1 ml of physiologic
saline intradermally with fine needle over the
forearm. Read after 24-48 hours. Pustules or
papules suggest the diagnosis of Behcet’s
disease. Histology shows neutrophilic
infiltrate or vasculitis.
• Testing sensation and palpation of
peripheral nerves may be required to fulfil
one of the cardinal features of leprosy and
thus help in its diagnosis.
LABORATORY AND SPECIAL TESTS
They may be needed to confirm the diagnosis:
1. Wood’s light examination: It is useful in
detecting fungal infections of the scalp
(bluish-green fluorescence in tinea capitis
caused by Microsporum species—Micros-
porum canis and Microsporum audouinii),
tinea versicolor (yellow fluorescence),
erythrasma (coral red fluorescence),
porphyrins in patients with porphyria
cutanea tarda (Urine will produce bright red
fluorescence), trichomycosis axillaris
(orange fluorescence), Pseudomonas in-
fection (green fluorescence), etc. In scabies,
fluorescein solution fills burrows. In
pigmentary disorders, vitiligo, piebaldism,
and ash leaf macules of tuberous sclerosis,
the lesions become prominent.
2. KOH preparation: Indicated when
infection with fungi or yeast is suspected,
e.g. dermatophytosis, tinea versicolor,
3. Tzanck test: It is used in the diagnosis of
various skin disorders characterised by
vesicles, pustules, bullae and erosions and
in particular in viral infections like herpes
simplex, herpes zoster and varicella
4. Gram’s stained pus smear: Indicated for
pyogenic infections, vaginal and urethral
5. Tissue smear: It is used for diagnosis of
donovanosis (granuloma inguinale).
6. Dark field (ground illumination) test:
Primary and secondary syphilis can be
easily diagnosed by demonstrating
7. Wet preparation: It is utilized for diagnosis
of trichomonal infestation of the genital
8. Slit skin smear: This test is performed on
leprosy patients to demonstrate acid-fast
bacilli in skin smears.
9. Lepromin test: It is useful for classification
of leprosy and is strongly positive in
tuberculoid leprosy and mildly positive in
borderline tuberculoid leprosy. It is negative
in borderline borderline, borderline
lepromatous and lepromatous leprosy.
10. Dermatoscopy (Epiluminescence micros-
copy, dermoscopy): Method of observing
superficial layers of skin using 10-100 X
magnification with oil immersion. Both
hand held and computer assisted
instruments are available. It is used for
differential diagnosis of pigmented skin
lesions, melanoma, for detailed
examination of nail fold capillaries,
Wickham’s striae, scabies burrows (hang
glider sign), surface of verrucae and the
scalp surface (cadaver hairs and
exclamation point hairs suggest alopecia
areata, loss of follicular openings indicates
scarring alopecia and follicular
hyperkeratosis point towards lichen
11. Biopsy: Most frequently skin biopsy is taken
to confirm a clinical diagnosis or to aid in
the establishment of a diagnosis where
clinical diagnosis is not apparent.
Essentials in Dermatology30
13. HIV antibody detection test
14. Culture and sensitivity test
15. Patch testing
16. Prick testing
17. Intradermal testing
18. LE cell phenomenon
19. Mouse foot pad inoculation
21. Hair examination and counts
22. Trichogram- method for analyzing hair
bulbs to identify in what stage hairs are
being lost and thus to distinguish between
different types of hair loss.
23. Electron microscopy
Five Thoughts for the Students in the
Field Of Dermatology
1. Diagnosis is the art of recognition, not the
science of cognition
2. The best diagnosticians are the ones with the
best visual memories
3. The best history is taken by one who already
knows the diagnosis
4. If puzzled, limit yourself to three working
5. A good colour atlas (a memory of 75 diseases
allows you to immediately recognize 95% of
all the skin lesions you will ever see) and a
good dermatopathologist are your best
Bacterial Infections 31
Normal human skin is colonized soon after birth
by a large number of bacteria that live as
commensal on the epidermis and epidermal
appendages. Coagulase negative staphylococci
(S. epidermidis) are inoculated during vaginal
passage; coryneform bacteria take up residence
on neonatal skin shortly after birth; and within
several weeks after birth, the flora of neonatal
skin is similar to that of adults. Staphylococcus
aureus is persistent member of the microbial
flora in 10 to 20% of the population. As many as
84% of healthy individuals have occasional
carriage of S. aureus in their anterior nares.
Pyoderma is a common purulent infection of the
skin caused by staphylococcal or streptococcal
organisms. They can be classified as primary
6 Bacterial Infections
Primary pyodermas are further divided into
non-follicular and follicular for clinical
application (Table 6.2) and on the basis of
organism involved (Table 6.3).
Non-bullous impetigo (Impetigo contagiosa of
• It is caused by S. aureus or group A
Streptococcus or both
• Occurs in children of all ages, common
in preschool and young school children
• Commonly over the face (especially
around nares) or extremities after trauma
• The initial lesion is a transient vesicle or
pustule that quickly evolves into a honey
coloured crusted plaque (Fig. 6.1)
• Surrounding erythema may be present
Table 6.1: Distinctive features of pyodermas
Primary pyodermas Secondary pyodermas
1. Invasion of normal skin by bacteria 1. Develop in areas of already damaged/compromised skin
2. Single species of bacteria involved 2. Mixture of organisms involved
3. Appearance of lesions is characteristic 3. Not characteristic
e.g., impetigo, erysipelas, furuncle
4. Treatment is clear cut – Drugs aimed 4. Role of antibacterial treatment less defined.
at the microorganism Here, the aim is to treat the underlying process
Essentials in Dermatology32
Table 6.2: Non-follicular and follicular pyodermas
A. Non follicular pyodermas include
B. Follicular pyodermas include
Table 6.3: Cutaneous diseases caused by
staphylococci and streptococci
1. Cutaneous diseases caused by
A. Direct infection of skin:
Impetigo, ecthyma, folliculitis, furunculosis,
B. Due to effect of bacterial toxin:SSSS, TSS.
2. Cutaneous diseases caused by streptococcus:
A. Direct infection of skin:
Impetigo, ecthyma, erysipelas, cellulitis,
vulvovaginitis, perianal infection, blistering
dactylitis, necrotizing fasciitis.
B. Due to effect of bacterial toxin:
Scarlet fever, toxic shock like syndrome
• Regional lymphadenopathy in up to 90%
of patients with prolonged untreated
• In severe cases, there may be fever,
adenitis and constitutional symptoms
• Differential diagnosis: 1.Tinea corporis –
has dry, scaly, advancing edge with
central clearing. 2. Ecthyma- charac-
terized by crusted ulcers (not erosions).
• Earlier bullous impetigo in neonates was
popularly known as pemphigus
• S. aureus (phage group II) is the causative
• Occurs commonly in the newborn and in
• Bullae (flaccid) rapidly evolve from
vesicles on areas of grossly normal skin
(Fig. 6.2) due to local production of
exfoliative toxin A and B.
• Differential diagnosis: Pemphigus
vulgaris-Generally occurs in young
adults. Erosions show no tendency to
heal, Nikolsky’s sign and bulla spread
sign are positive. More importantly,
mucosal erosions are more commonly
Fig. 6.1: Impetigo contagiosa–honey colored
crusted lesions over the face of a child
Fig. 6.2: Bullous impetigo–large pus filled blisters
over the trunk of a child
Bacterial Infections 33
Complications of Impetigo
• Post-streptococcal acute glomerulonephritis–
S. pyogenes type M-49
• Scarlet fever
• Erythema multiforme
Rheumatic fever in not a complication of
streptococcal skin infection (but of streptococcal
• Consequence of neglected impetigo
• S. aureus and/ or group A Streptococcus
are causative agents
• Most commonly occurs on the lower
extremities of children or neglected
• Poor hygiene and neglect are key
elements in pathogenesis.
• Dirty grayish-yellow crust surmounts a
“punched out” ulcer (Fig. 6.3).
Pyoderma affecting the hair follicles, classified
according to depth of invasion.
• Also known as follicular or Bockhart’s
• A small fragile dome shaped pustule
occurs at the infundibulum of a hair
follicle, often on scalps of children and in
the beard area, axilla, extremities and
buttocks of adults.
• Differential diagnois: Miliaria pustulosa
– non follicular pustules are wide spread,
which occur in hot and humid conditions
Sycosis barbae is a deep folliculitis with
perifollicular inflammation occurring in the
bearded areas of the face (Fig. 6.4) and upper
1. Pseudofolliculitis– Papules/pustules are
irregularly scattered at the site of ingrowing
beard hairs. Neck and angle of jaw (vs.
sycosis barbae– upper lip and below angles
of jaw) are preferentially involved.
2. Tinea barbae– Site involved is usually
submaxillary region or the chin. Hairs are
Fig. 6.3: Ecthyma–crusted lesion over the leg with
Fig. 6.4: Sycosis barbae– grouped follicular based
crusted lesions in the beard area of the face
Essentials in Dermatology34
broken or loosened (easy and painless
pluckablity) in the affected area. Loss of hair
is the norm. Suppurative or granulomatous
nodules rather than pustules characterize this
condition. Spores and hyphae can be demon-
strated in the hair by KOH examination.
3. Herpetic sycosis is usually limited for a few
days and invariably shows vesicles even in
4. Acne vulgaris is polymorphous condition
mainly of glabrous skin of the face where
comedones are the hallmark of that condition
Lupoid sycosis is deep, chronic form of
sycosis barbae associated with scarring usually
occurring as circinate lesion. Pustules and
papules surround a central scar (Fig. 6.5).
Differential diagnosis: Lupus vulgaris is
characterized by areas of scarring on one side
and progression on the other side. There is
absence of pustules in the lesions but it
demonstrates apple jelly nodules on diascopy.
Furuncles and Carbuncles
• A furuncle or boil is a deep-seated
inflammatory nodule that develops about a
hair follicle, often evolving into an abscess
(Fig. 6.6). They arise in hair bearing areas,
particularly in regions subject to friction,
occlusion, and perspiration.
Differential diagnosis: Folliculitis-
Inflammatory change is confined within the
follicle without any surrounding inflam-
mation – hence presents as a pustule whereas
furuncle presents as a nodule. There is less
pain and it heals without scar formation.
Cystic acne- Associated with other lesions of
acne – comedones, papules and pustules and
acne scars and it is confined to face and trunk.
• A carbuncle is a cluster of furuncles, more
extensive, deeper, communicating, in
filtrated lesion that develops when
suppuration occurs in elastic skin. It usually
involves the nape of the neck, back or thighs
and usually occurs in the setting of under-
lying diabetes mellitus, alcoholism, malnu-
trition, blood dyscrasias, iatrogenic or other
immunosuppression including HIV
infection. Fever, malaise, prostration
Differential diagnosis: Anthrax – charac-
terized by painless, hemorrhagic crusted
(blackish eschar) lesion with surrounding
gelatinous edema out of proportion to the
extent of the lesion.
Fig. 6.5: Lupoid sycosis–scarring alopecia in the
beard area showing active pustular lesions at the
Fig. 6.6: Furuncle–a red tender suppurated nodule
in a case of erythroderma
Bacterial Infections 35
Staphylococcal paronychia: Clinically, skin and soft
tissue of proximal and lateral nail fold are red,
hot and tender, and if not treated, can evolve to
abscess formation. In contrast, chronic or
recurrent paronychia caused by Candida albicans
is an infection of the space underneath the nail
Toxin Mediated Syndromes
Staphylococcal scalded skin syndrome
(SSSS) (Ritter’s disease)
• This is the most severe form of skin disease
due to the exfoliative exotoxins (A and B)
produced by S. aureus of group II, phage type
71 or 55 and is characterized by generalized
bulla formation and exfoliation. Most
commonly involves neonates and young
children, but also in adults with renal
compromise. Typically, the patient has fever
and is irritable. The changes usually begin
periorificially or in body folds (Figs 6.7 and
6.8). Then they spread rapidly. Nikolsky’s
sign is positive even on apparently normal
skin. One should culture the perineum, eyes,
ears, nose and throat, looking for S. aureus as
the focus of infection is located at a distant
site. The bacteria can not be cultured from
the skin. For differential diagnosis Table 6.4.
Toxic Shock Syndrome
• TSS is a multiorgan systemic illness due to
exotoxin (TSS-Toxin 1) producing strains of
• Case definition
1. Temperature of 38.9o
C or higher
2. Erythematous eruption
Figs 6.7 and 6.8: SSSS–typical periorificial and body fold involvement with peeling skin
Table 6.4: Differential diagnosis of SSSS from toxic epidermal necrolysis (TEN)
Staphylococcal scalded skin syndrome (SSSS) TEN
1. Age – less than 5 years 1. More than 40 years
2. Skin shows marked tenderness 2. Mild to moderate tenderness
3. Distribution – face, neck , axilla, groin 3. No clear distribution
4. Mucoca – not involved 4. Involved
5. Prognosis – good 5. Poor
6. Histology – subgranular split due to acantholysis 6. Necrosis of epidermis
Fig. 6.7 Fig. 6.8
Essentials in Dermatology36
3. Desquamation of palms and soles 1 to 2
weeks after onset
5. Involvement of 3 or more other organ
• About 85 to 90 percent of cases of TSS have
occurred in women at the time of mens-
truation; almost all had been tampon users
(particularly of super absorbent types).
• Differential diagnosis:
1. SSSS– It has the presence of bullae,
Nikolsky’s sign is positive with skin
tenderness, but systemic organs are not
involved and patient appears well-
2. Scarlet fever– not usually associated with
hypotension and shock.
3. Kawasaki’s syndrome– prolonged fever,
cardiac involvement, generalized
lymphadenopathy and absence of
The major pathogen belongs to group A and is
referred to as Streptococcus pyogenes. Streptococci
colonise damaged skin, although less frequently
than staphylococci. Major complications
following streptococcal infection are rheumatic
fever (following Streptococcal pyogenes
pharyngitis), acute glomerulonephritis (both
throat and skin infection), erythema nodosum
and guttate psoriasis, and scleredema of Buschke
(following throat infection).
Impetigo and Ecthyma already discussed.
Crowding, poor hygiene, and neglected minor
skin trauma contribute to the spread of
streptococcal impetigo in families.
Cellulitis and Erysipelas
• Predominantly streptococcal disease,
Staphylococcus aureus is occasionally
• Cellulitis is an acute, subacute or chronic
infection of loose connective tissue, mainly
of subcutaneous tissue whereas erysipelas is
a bacterial infection of the dermis and upper
• Erythema, warmth, swelling and tenderness
are constant features (Fig. 6.9). In erysipelas,
the edge of the lesion is well defined and
raised, but in cellulitis it is diffuse.
• In erysipelas, blistering is common.
• Except in mild cases, there are constitutional
• The leg is the commonest site; the next most
frequent site for classical streptococcal
erysipelas is face.
• Milian’s sign – cellulitis of the face does not
involve pinna, unlike erysipelas (as there is
no subcutaneous tissue there).
• Without effective treatment, complications
are common-fasciitis, myositis, subcutaneous
abscesses, septicaemia, and nephritis.
• For presumed streptococcal infection,
penicillin is the treatment of choice.
Fig. 6.9: Cellulitis–lower leg showing shiny
erythema and edema
Bacterial Infections 37
• This is nearly always a group A streptococcal
infection in children or teenagers.
• A large blister containing thin seropurulent
fluid forms on the distal phalanx, usually of
a finger, typically on a phalangeal pad.
Perianal Streptococcal Infection
• It occurs in children aged 1-10 years and is
characterized by intense perianal erythema,
perianal soreness, pain on defecation, faecal
retention and blood-streaked stools.
• Streptococcus pyogenes accounts for 10% of
cases of vulvovaginitis in prepubertal girls.
Toxin Mediated Streptococcal Disease
• Scarlet fever and streptococcal toxic shock
like syndrome are due to toxins.
• Scarlet fever is a diffuse erythematous
eruption resulting from the production and
subsequent circulation of pyrogenic
exotoxins A, B, C (erythrogenic toxin)
produced by group A streptococci usually
located in pharynx. Incubation period – 2 to
5 days – starts with an acute tonsillitis. Rash
appear on the 2nd day as finely punctuate
erythema “Sunburn with goose-pimples”.
Other features include Pastia’s lines
(transverse streaks in the skin folds due to
capillary fragility), pallor around mouth, red
strawberry tongue, and high fever.
Myocarditis may complicate this condition.
• Group A streptococci cause an acute
multisystemic syndrome coined toxic-shock
–like syndrome (TSLS) resembling that
caused by S. aureus.
Necrotizing Fasciitis (Streptococcal
• It represents cellulitis that has progressed to
gangrene of subcutaneous tissue followed by
necrosis of overlying skin (Fig. 6.10).
• It is not only caused by group A streptococci
but also due to other bacterial species
(mixture of anaerobes/facultative orga-
1. Gram’s stained smear from the purulent
material may demonstrate streptococci or
staphylococci or both.
2. Culture and sensitivity: Swabs taken from
infected sites may be sent for culture and
sensitivity, so that appropriate antibiotic may
be instituted to treat the condition.
3. Tzanck smear in SSSS shows acantholytic
4. Histopathology: Histopathological exami-
nation is hardly required for the diagnosis.
1. General measures such as improved
hygiene, loose light weight porous clothing,
regular bathing, use of antiseptics in bath,
antibacterial soaps, etc.
Fig. 6.10: Necrotizing fascitis—cellulitis progressing
to gangrene over the leg
Essentials in Dermatology38
2. Wet compresses: Condy’s compresses for
crusted lesions of pyoderma.
3. Incision and drainage is indicated when
furuncle has become localized and shows
4. Topical antibacterial agents such as gentian
violet, neomycin, fusidic acid or mupirocin.
5. Systemic antibacterial agents: Systemic
antibiotic therapy is indicated–
i. For extensive lesions of pyoderma
ii. For erysipelas, cellulitis, carbuncle,
furunculosis, SSSS, etc.
Penicillin is preferred for streptococcal
infection whereas penicillinase resistant
penicillin such as cloxacillin and cephalosporins
are required for staphylococcal infections. Oral
antibiotics (e.g., rifampicin 600 mg orally daily
for 10 days) have been effective in eradicating S.
aureus from most nasal carriers for periods of up
to 12 weeks in cases having recurrent
furunculosis. Intranasl application of 2%
mupirocin ointment for 5 days can eliminate S.
aureus nasal carriage in 70% of healthy
individuals for up to 3 months.
• Causative agent-Corynebacterium minutis-
simum, diphtheroids bacillus, gram positive,
non spore forming rod shaped organism.
• Bacterial infection of the intertriginous areas
like axilla, groin, gluteal cleft, inframammary
folds, umbilicus and toe web spaces.
• Usually manifest with asymptomatic red
brown macules with sharp border (Fig. 6.11).
• The best way to make the diagnosis is Wood’s
light examination for coral red fluorescence.
• Differential diagnosis: Hyperpigmented
tinea versicolor (asymptomatic in nature)
may appear like erythrasma. It predo-
minantly affects upper trunk, individual
lesions are small, but not erythematous and
satellite lesions are more commonly seen than
erythrasma. KOH examination and culture
from the lesions may clinch the diagnosis.
Tinea cruris is characterized by pruritic well
defined annular plaques with peripheral rim
of papulopustules, and satellite lesions.
• C. minutissimum can be cultured under
• A short course of systemic erythromycin is
the easiest method of treatment. Topical
imidazole creams are also effective.
• Causative agent- Corynebacterium tenuis.
• Collections of this bacteria forms concretions
on hairs, usually in the axilla.
• The axillary hairs are surrounded by white-
yellow (Fig. 6.12), red or black, difficult to
remove concretions that extend for several
• Diagnosis is established by examining hair
under microscope (Fig. 6.13), if necessary to
culture the organism.
Fig. 6.11: Erythrasma–asymptomatic brownish
macular lesion with fine scaling in the axilla
Bacterial Infections 39
• Differential diagnosis: Phthiriasis pubis can
be differentiated by its associated pruritis and
crawling sensation. Piedra can be
differentiated by its gritty hard feeling and
by doing a KOH examination.
• The easiest treatment is to shave the area and
treat the regrowing hairs with any topical
Fig. 6.12: Trichomycosis axillaris–yellow
discoloration of axillary hairs due to concretions
Fig. 6.13: Trichomycosis axillaris–same patient's
axillary hair under light microscope showing
concretions over the hair shaft
• Causative agent- Corynebacterium species,
Streptomyces species, Dermatophilus congo-
lensis and Micrococcus sedentarius.
• Multiple pitted defects, 2-5 mm in size occur
in thick horny layer of soles (Fig. 6.14).
• The key factor is maceration, usually arising
from hyperhidrosis, prolonged wearing of
shoes and improper hygiene.
• Differential diagnosis: The lesions are easily
recognizable, but simple hyperhidrosis,
erythrasma and tinea pedis have to be
• Topical erythromycin solution or benzoyl
peroxide gel can be applied once or twice
daily. Remove aggravating factors, if
• Botryomycosis is a chronic suppurative,
granulomatous disorder of bacterial origin.
True non- filamentous aerobic and anaerobic
bacteria such as Staphylococcus aureus,
Pseudomonas species, Proteus vulgaris,
Escherichia coli or Micrococcus cause it.
• Botryomycosis needs to be differentiated
from two other granulomatous diseases that
Fig. 6.14: Pitted keratolysis–soles demonstrating
Essentials in Dermatology40
Fig. 6.15: Botryomycosis–swelling of the foot with
multiple nodules over it
form granules - mycetoma and actino-
mycosis, since clinically it has similar features
• Effective treatment of botryomycosis
depends on various factors such as the
causative agent, location of the lesion and
immune status of the host. Various drugs,
mostly as single agents given for several
weeks, have been successfully used in
botryomycosis including trimethoprim-
sulfamethoxazole, minocycline, erythro-
mycin and cefazolin. In addition to
antibiotics, surgical excision and drainage of
lesions may be useful in certain patients.
• Actinomycosis is a chronic suppurative
infection caused by anaerobic Actinomyces
species. Actinomycetes are bacteria producing
filamentous and branching hyphae.
• Pathogenic organisms of these genera,
namely Actinomyces israelii exists as a
commensal in the oral cavity, tonsillar crypts
and genital mucosa.
• This organism gains entry when there is a
disruption of mucosal barrier in the form of
trauma or surgery. The resultant disease,
actinomycosis is characterized by an early
inflammatory phase which resembles
cellulitis and a more typical chronic phase,
which presents as single or multiple
indurated swellings (usually fibrosis).These
swellings become soft and fluctuant and later
suppurate, sometimes forming sinus tracts
discharging yellow colour granules. These
so called “sulphur granules” are lobulated
masses of intertwining filaments.
• Human infections are categorized based on
anatomical sites, namely cervicofacial (lumpy
jaw), thoracic, abdominal, pelvic and primary
• Cervicofacial actinomycosis is the most
common clinical presentation. It commonly
follows dental extraction and presents as
painful, indurated soft tissue swelling located
at the angle of the jaw.
• Thoracic infection occurs due to aspiration
and it involves lungs and pleura.
• Actinomycosis of gastrointestinal tract most
commonly develops in ileocecal region and
presents as appendicitis or slow growing
• Pelvic actinomycosis occurs in women and
is usually associated with the use of
• Primary cutaneous actinomycosis is a rare
type and probably occurs due to direct
implantation of the organism. It usually
occurs on the exposed skin (Fig. 6.16).
Fig. 6.16: Actinomycosis–scalp showing ulcerated
indurated nodules with sulphur granules
Bacterial Infections 41
• A definite diagnosis of actinomycosis cannot
made be on clinical grounds alone.
Demonstration of sulphur granules, grams
stain and culture from the appropriately
obtained specimen is needed to confirm the
diagnosis. Histopathology reveals granular
colonies from which delicate mycelial
filaments radiate. These colonies are
surrounded by a chronic inflammatory
• Actinomycosis may resemble various chronic
inflammatory diseases such as tuberculosis,
• Dramatic response to penicillin therapy
• Causative agent- Bacillus anthracis, gram
• The most common form of infection with
Bacillus anthracis is an acute cutaneous lesion
called “malignant pustule.”
• Anthrax is primarily a disease of domestic
and wild animals, but humans become
accidentally involved through exposure to
animals and their products.
• Human anthrax occurs in three clinical forms:
1) cutaneous anthrax due to direct contact
with contaminated meat, carcasses, hides,
hair, wool or bone, 2) inhalational anthrax
(Woolsorter’s disease) due to inhalation of
spores and 3) gastrointestinal anthrax due to
ingestion of contaminated meat or milk.
Anthrax meningitis occurs secondary to skin
lesions, but it can complicate the other two
• Cutaneous anthrax usually begins as a
painless, pruritic papule within 3 to 10 days
of inoculation. It rapidly progresses into a
serous or serosanguineous vesicles, which
ulcerate with a central black eschar,
surrounded by a ring of vesicles within 36
hours (Figs 6.17 and 6.18). Perilesional
oedema can be extensive. Toxic features
occur in 50% of cases only and healing occurs
in 1 to 3 weeks with variable scarring.
• The following clinical features are strongly
suggestive of cutaneous anthrax -
1. The presence of edema out of proportion
to the size of the lesion.
2. Lack of pain during the initial phases of
3. The rarity of polymorphonuclear
leucocytes from vesicular fluid on gram’s
stain and distinctive box car arrangement
of bacillus anthracis (Fig. 6.19).
Figs 6.17 and 6.18: Cutaneous anthrax (Malignant pustule)–typical painless lesion with central blackish
eschar surrounded by wreath of erythema, edema and vesiculation
Fig. 6.17 Fig. 6.18
Essentials in Dermatology42
• Differential diagnosis: Carbuncle -
Tenderness is prominent and there is
presence of multiple furuncles in a group.
Cow pox and sporotrichosis are other
differential diagnoses. The history, rapid
course, clinical appearance and lack of
lymphangitis should suggest the diagnosis
of anthrax which should be confirmed by
• Since 20% of untreated cases of cutaneous
anthrax develop bacteraemia, which leads to
rapid death, cutaneous anthrax should be
treated energetically with penicillin.
Fig. 6.19: Anthrax–"Box car" arrangement of
bacillus anthracis in gram's stained smear
Ciprofloxacin, erythromycin, tetracycline
and chloramphenicol are alternative drugs
for penicillin sensitive patients.
• Causative agent: Bartonella henselae (organism
also causes Cat Scratch disease); rarely
• Infection is most common in HIV/AIDS
patients, causes endothelial proliferation and
produces vascular tumors.
• Clinically, lesions are rapidly growing
pyogenic granuloma like papules and
nodules, which often ulcerate.
• Purple, papular and nodular vascular lesions
may resemble Kaposi’s sarcoma.
• Diagnosis is based on demonstration of
organism in the skin biopsy tissue section by
Warthin Starry staining. Blood cultures are
positive in half of the cases.
• Differential diagnosis: Pyogenic granuloma
and Kaposi’ sarcoma are close differential
diagnosis, differentiation can be made by
histopathological examination and
demonstration of the organism by Warthin
• The mainstay of treatment is erythromycin.
Alternatively, doxycycline or ciprofloxacin
can be used.
Viral Infections 43
Many viral infections have cutaneous
manifestations. These infections may sometimes
be limited to the skin as in warts or molluscum
contagiosum. In systemic viral infections, the
frequency of skin lesions may range from almost
always, as in varicella, to infrequently, as in
Viral infections of skin are characterized by
a definite morphology and distribution. Most of
the infections can be clinically diagnosed fairly
and accurately without the need of sophisticated
laboratory diagnostic aids. Five groups of viruses
can affect the skin or adjoining mucous
membrane surfaces. All except two (picorna
virus group and retroviruses group) belong to
Viruses can be seen with the light microscope
only when aggregated into inclusion bodies.
Inclusion bodies are roughly spherical. Their
average size is about 7 µm, the size of an
erythrocyte. They are seen in three groups of
viruses and are of two types.
1. Intranuclear inclusion bodies are seen in the
herpes virus group and papilloma virus
2. Intracytoplasmic inclusion bodies are seen
in the poxvirus group.
In India, molluscum contagiosum is the
predominant viral skin infection followed by
7 Viral Infections
warts, herpes simplex, herpes zoster and
• Molluscum contagiosum is caused by up to
four closely related types of poxviruses,
MCV-1 to - 4 and their variants.
• The incubation period for the molluscum
contagiosum (MC) has been reported to be
between 14 and 50 days.
• Skin to skin transmission is presumed to be
the method of spread, including auto-
inoculation (the Koebner phenomenon), as
well as contact with fomites.
• It mainly affects children, sexually active
adults and persons with impaired cellular
immunity including HIV infection
• In small children, virtually all infections are
caused by MCV-1 whereas in patients
infected with HIV, however, MCV-2 causes
the majority of infections (60%), suggesting
that HIV infection associated molluscum
does not represent recrudescence of child-
hood molluscum. In all forms of infection, the
lesions are relatively similar.
• Individual lesions are smooth surfaced,
firm, dome shaped pearly papules
averaging 3 to 5 mm in diameter. Some
Essentials in Dermatology44
“giant” lesions may be up to 1.5 cm in
• A central umbilication is characteristic (Fig.
• Children more typically develop lesions on
the face (Fig. 7.2), trunk and extremities,
although perineal, scrotal (Fig. 7.3), perianal
(Fig. 7.4), and groin lesions may be present
as part of a wider distribution.
• Clinically, molluscum in HIV positive
persons appears to be transmitted both by
sexual and nonsexual routes. The lesions are
more common on the face and neck (Figs 7.5
• It is made clinically when necessary,
histological examination is diagnostic.
Fig. 7.1: Molluscum contagiosum—typical
Fig. 7.2: Molluscum contagiosum—lesions
occurring over the face in a child
Fig. 7.3: Molluscum contagiosum—lesions
occurring over genitalia in a child
Fig. 7.4: Molluscum contagiosum—lesions over the
gluteal area and thigh in a child
Viral Infections 45
• Microscopic examination of a lesion crushed
on a slide and left stained or unstained with
Wright’s, Giemsa, Gram’s, or Papanicolaou
stains demonstrates the inclusion bodies
(Henderson Paterson bodies).
• Solitary MC may resemble pyogenic
granuloma, keratoacanthoma or epithelioma.
• Cutaneous cryptococcos is histoplasmosis,
Penicillium marneffei infection, and basal cell
carcinoma have been mistaken for
molluscum in patients with AIDS.
• In children, they may be left alone
• Curettage– Individual lesions can be treated
• Trichloroacetic acid (30-100%) application
• 10% KOH application
• Podophyllin – 10% to 25%
• Silver nitrate
• 5-FU topically
• Topical cantharidin, tretinoin (0.05% - 0.1%),
cidofovir (1-3%), and imiquimod (5%) are
• Oral cimetidine or intravenous cidofovir can
be used in widespread lesions.
HUMAN PAPILLOMAVIRUS INFECTION
• Human papillomavirus (HPV) has been
associated with a broad spectrum of disease
that ranges from asymptomatic latent
infection to warts to squamous cell
• This virus infects mucosal and cutaneous
sites of immunocompetent as well as
• It represents the most common mucocut-
aneous viral infection, and 3 to 5% of all
patients have clinically evident warts.
• Warts, or verrucae, are benign proliferations
of the skin and mucosa that result from
infection with papillomavirus.
• These viruses do not produce acute signs or
symptoms but induce slow-growing lesions
that can remain subclinical for long periods
• These warts assume many clinical forms –
common warts (verrucae vulgaris), filiform
warts (digitate warts), flat warts (verrucae
plana), plantar warts, genital warts
(condylomata acuminata), oral and laryngeal
Fig. 7.5: Molluscum contagiosum—lesions around
eye in a HIV patient
Fig. 7.6: Giant molluscum contagiosum just below
the eye in an adult HIV patient
Essentials in Dermatology46
papillomas and epidermodysplasia verruci-
formis. HPV types 1,2,3,4,7 cause first four
forms of warts commonly. Genital warts are
usually due to HPV types 6, 11, 16 and 18.
• Warts occur at any age, but are unusual in
infancy and early childhood, the incidence
of warts increases during the school years.
• Incubation period has been estimated to
range between a few weeks to more than 1
• Warts are spread by direct or indirect
• Impairment of epithelial barrier function by
moisture or trauma is predisposing factor.
Common warts: They are due mainly to HPV-2
and are characterized by symptomless, firm
papules with a rough, horny surface, range in
size from less than 1 mm to over 1 cm in
diameter, and by confluence can form large
masses. They are most commonly situated on the
backs of hands and fingers (Fig. 7.7). They need
to be differentiated from calluses. Warts do not
have dermatoglyphics as opposed to calluses in
which these lines are accentuated.
Plantar warts: A plantar wart at first appears as
a small, shining, sago grain papule, but soon
assumes the typical appearance of a sharply
defined, rounded lesion, with a rough keratotic
surface surrounded by a smooth collar of
thickened horn. Most plantar warts are beneath
pressure points, the heel or the metatarsal heads.
Mosaic warts are so described from the
appearance presented by a plaque of closely
grouped warts. Pain is a common, but variable
Differential diagnosis is corn/s.
• On paring, epidermal ridges are seen to
continue without interruption in corns,
whereas in warts epidermal ridges are
interrupted on the surface of the wart.
• Paring shows multiple bleeding points or
black dots representing thrombosed
capillaries in warts.
• Corns have a hard, painful translucent
• Lateral pressure on a wart causes pain, but
corn is painful on vertical pressure.
Plane warts: They are due mainly to HPV 3 and
10, and are smooth, flat or slightly elevated,
skin colored or pigmented. The face (Fig. 7.8)
and the backs of hand and shin are the sites of
predilection. In differential diagnosis, lichen
Fig. 7.7: Common warts—rough surfaced keratotic
papules over the dorsa of hand
Fig. 7.8: Plane warts—smooth surfaced papules
over the face
Viral Infections 47
planus causes most difficulty. Lichen planus
favours the flexor aspects of the forearms, is
unusual on the face and is often itchy. The
mucous membranes may be involved. The flat
polygonal papules are lilac-pink and smooth and
may show Wickham’s striae.
Filiform and digitate warts: Occur commonly
in the male, on the face and neck. They are
irregularly distributed, often clustered. Digitate
warts often in small groups also occur on the
scalp in both sexes where they are occasionally
confused with epidermal naevi.
Anogenital warts: It has been estimated that up
to 30 to 50% of sexually active adults are infected
with HPV, making it the most common viral STD
in some STD clinics. Most of them occur on the
penis, scrotum, urethral meatus and perianal
area in men and on the introitus, vulva,
perineum and perianal area in women. The four
morphological types are—
1. Cauliflower like (condyloma acuminata)
4. Flat topped.
Bowenoid papulosis: is a clinicopathologic
entity in which HPVs (HPV-16 is the most
common that has been linked to it) have been
identified. These appear as 2 to 3 mm papules
often multiple over the external genitalia.
Histologically, there is cellular atypia resembling
Buschke Lowenstein tumor (giant condyloma):
This lesion emerges from a preexisting benign
anogenital wart before developing into a
verrucous carcinoma. Usually, it is associated
with type 6 and 11. Clinically, it resembles a
large aggregate of condyloma acuminata over
the glans penis (Fig. 7.10), foreskin, vulva or anal
Epidermodysplasia verruciformis: Usually
manifests in childhood with widespread warts.
It is an inherited disorder in which there is wide
spread and persistent infection with HPV giving
rise to a combination of plane warts, pityriasis
versicolor like lesions and reddish plaques
(Figs 7.11 and 7.12).
Multiple warts that do not resolve
spontaneously, recur after treatment, persist for
years, and have an unusual morphology may
suggest epidermodysplasia verruciformis.
Malignant change is very common but
metastasis is rare.
Fig. 7.9: Genital warts—cauliflower like lesion of
condyloma acuminata over the glans penis along with
Fig. 7.10: Buschke Lowenstein tumor—a large
verrucous growth seen involving the glans penis
Essentials in Dermatology48
• Clinical diagnosis of warts is often sufficient
but atypical, subclinical or dysplastic lesions
may need laboratory confirmation of HPV
• Other than histopathology of lesion
(Koilocytosis in the stratum granulosum and
stratum spinosum), detection of virus
particles by electron microscopy,
immunocytochemistry using type specific
antibodies, DNA hybridization on tissue
extracts and polymerase chain reaction may
Most common warts disappear spontaneously
within 2 year or with simple nonscarring
treatment. Commonly employed modalities of
• Chemical cautery: Trichloroacetic acid is
used for common warts, filiform warts and
• Electrosurgery: Electrodesiccation or
electrofulguration may be done.
• CO2 laser ablation.
• Cryotherapy: Either using liquid nitrogen
using dipstick method or spray method, or
nitrous oxide cooled probes.
• Keratolytic agents like 10 to 20% salicylic
acid topically may be used.
• Formalin soaks with 2 to 3% formalin in
water every day for 15 minutes is useful for
• Curettage or surgical excision for warts
unresponsive to topical treatment.
• Topical retinoic acid for flat warts.
• Cantharidin causes blistering and focal
destruction of the epidermis.
• Cidofovir and 5-FU topically.
• Intralesional bleomycin.
• Injection of 0.1 ml of 1:1000 candida antigen
in the base of each wart.
• Topical sensitizer and systemic immuno-
modulators (Interferon, especially interferon
Fig. 7.11: Epidermodysplasia verruciformis—
pityriasis versicolor like lesions over the forearm
Fig. 7.12: Epidermodysplasia verruciformis—verruca
vulgaris like lesions aggregating over the dorsa of the
Viral Infections 49
alpha intralesionally or intramuscularly) may
be employed depending upon the condition.
• Extensive warts, even in hitherto untreatable
epidermodysplasia verruciformis, have
improved or cleared with oral isotretinoin or
• Treatment of genital wart is discussed
separately in STD section but salient
treatment options are given below.
1. Podophyllotoxin 0.5% self administered
twice a day for 3 days in week for 4 weeks
or podophyllin 25% in tincture benzoin,
once or twice weekly.
2. Liquid nitrogen cryosurgery
4. Surgical excision
5. Chemical cautery
6. Topical imiquimod.
HERPES SIMPLEX INFECTION
• The word herpes is derived from the Greek,
meaning, “to creep”.
• The human herpes simplex virus consists of
two closely related viruses designated herpes
simplex virus type 1 (HSV-1) and herpes
simplex virus type 2 (HSV-2). The virus
causes a wide variety of mucocutaneous
infections and produce both primary and
• HSV -1 is generally associated with oral
infection, and HSV-2 is associated with
genital infection. However, HSV-1 genital
infection and HSV-2 oral infection are
becoming common, as a result of oral-genital
sexual contact and as most these infections
• Transmission of HSV infections most
frequently occurs through close contact with
a person who is shedding virus at a
peripheral site, mucosal surface, in genital or
• Neonates often have maternally acquired
HSV-1 antibodies, which decline to low levels
by 6 months of age.
• Primary herpetic infection of the mouth and
pharynx (Herpetic gingivostomatitis) is a
disease of children (Fig. 7.13) and young
adults. The peak years of incidence occur
between age 1 and 5. The usual onset is with
fever, sore throat, painful vesicles and
• The clinical manifestations of genital herpes
should be differentiated into first clinical
episode and recurrent episodes. The first
clinical episode can further be sub-divided
into primary infection, occurring in a person
without prior HSV 1 or 2 antibodies (true
primary) or nonprimary infection, occurring
in a person with prior HSV 1 or 2 antibodies.
The patients with first episode non primary
have lower frequencies of systemic
symptoms, shorter duration of pain, fewer
lesions and a shorter healing time compared
with the true primary infections.
• Primary genital HSV-2 and HSV-1
infections (Herpes genitalis) are
characterized by frequent and prolonged
systemic and local symptoms. Fever,
headache, malaise and myalgia are reported
in 40% of men and 70% of women with
primary HSV-2 infection. Widely spaced
pustular or ulcerative lesions on the external
genitalia are the most frequent presenting
signs. Ulcerative lesions persist for 4-15 days
until crusting or re-epithelization occurs.
Fig. 7.13: Primary herpetic gingivostomatitis—lips
also involved along with oral cavity with vesiculation,
erosions and hemorrhagic crusting
Essentials in Dermatology50
• Recurrences occur in 30-50% of cases of oral
herpes (Fig. 7.14) but are more frequent after
genital herpes infection (Fig. 7.15),
developing in 95% of those with type 2 HSV
compared with 50% in type 1 infection. They
are usually triggered by fever, respiratory
tract infection, ultraviolet radiation,
trigeminal neuralgia, dental surgery or
dermabrasion. Recurrent infections differ
from primary infection in the smaller size of
the vesicles, their close grouping and absence
of systemic symptoms.
• Herpes simplex virus type 2 is now the most
common cause of genital ulceration among
the sexually transmitted diseases.
• Complications seen are eczema herpeticum
or Kaposi’s varicelliform eruption
(Widespread vesicular HSV lesions that arise
from primary or recrudescent infection in
patients with several dermatoses, particularly
atopic eczema.), neurological sequelae
(Aseptic meningitis, autonomic dysfunction
especially of the sacral dermatomes, rarely,
transverse myelitis, Bell’s palsy, Guillain
Barre syndrome may follow orolabial HSV
infection), extra genital lesions (extra genital
lesions is a common complication of first
episode primary genital herpes and is seen
over buttock, groin, or thigh, although finger
and eye can also be involved.), and
• Atypical HSV presentation occur relatively
often in HIV – infected patients, particularly
severe lesions occur over back, buttocks or
perianal region and these may expand to over
20 cm in diameter. Chronic HSV-2 ulcers of
more than 1-month duration are an AIDS –
defining illness. HSV may also cause life
threatening disseminated infection,
esophagitis, hepatitis and pneumonitis in
AIDS – patients.
Fig. 7.14: Recurrent herpes labialis—erosions seen
over the angle of mouth on one side
Fig. 7.15: Recurrent herpes genitalis—closely
grouped vesicles over the shaft of the penis
Fig. 7.16: Herpetic whitlow—grouped vesicles over
the great toe
Viral Infections 51
Clinical Entities Caused by HSV-1
1. Primary herpetic gingivo-stomatitis
2. Herpes labialis
3. Traumatic herpes—herpetic whitlow
(Fig. 7.16), herpes gladiatorum
4. Eczema herpeticum (Fig. 7.17)
5. Atypical presentations—Zosteriform herpes
simplex, varicella like eruption, neurologic
6. Ocular herpes simplex (Herpetic
7. CNS involvement
8. Disseminated herpes.
Clinical Entities Caused by HSV-2
1. Genital herpes
2. Recurrent lumbosacral herpes simplex
3. HSV infections in the newborn.
Fig. 7.17: Eczema herpeticum—widespread vesicular
eruption over the face in a patient with allergic contact
• The most reliable way to make a diagnosis is
by viral culture.
• A valuable clinical approach for making a
rapid diagnosis is Tzanck smear. Smears of
the bases of deroofed HSV vesicles are
stained with Giemsa or Wright’s stain and
examined by light microscopy for multi-
nucleated giant cells (Fig. 7.18).
• Primary infections can be diagnosed by
seroconversion or a rise in antibody titer.
1. For herpes gingivostomatitis- Diphtheria,
thrush, aphthosis, streptococcal infections,
and Stevens Johnson syndrome.
2. For recurrent herpes labialis-Aphthous
ulcers, erythema multiforme, and impetigo.
Acyclovir has modified the treatment outcome.
• Acyclovir 5 mg/kg body weight 8 hourly for
7 to 10 days.
Fig. 7.18: Tzanck smear showing multinucleated
Essentials in Dermatology52
• Others like eczema herpeticum and
disseminated herpes need to be treated
energetically on similar lines.
• Herpetic whitlow and keratoconjunctivitis
may be treated with oral acyclovir 200 mg 5
times a day for 7 to 10 days.
• Acyclovir 200 mg 5 times a day for 5 days or
• Acyclovir 400 mg tds × 5 days or
• Acyclovir 800 mg BD × 5 days
Alternative antiviral drugs are famciclovir
(125 mg, 250 mg twice daily) and valacyclovir
(500 mg, 1 gm twice daily).
For suppression of recurrences- Acyclovir
400mg twice a day for at least 1 year.
Treatment of Acyclovir Resistant
1. Cidofovir: Unlike acyclovir, it is phos-
phorylated only by cellular enzymes, hence
it is active against HSV with deficient or
altered thymidine kinase enzyme.
2. Foscarnet: It is a phosphonate viral DNA
polymerase inhibitor. It has been the
preferred agent for patients with acyclovir
resistant HSV infection.
Vaccines: The precise role of vaccines in future
management of HSV infection is yet to be
determined. Modification of frequency and
severity of recurrences may be achievable with
vaccines. The most promising candidate vaccines
are those based on HSV glycoproteins B and D.
VARICELLA-ZOSTER VIRUS INFECTION
• Varicella (chicken pox) and herpes zoster are
two distinct clinical entities caused by the
same virus, varicella zoster virus (VZV).
• Varicella is the primary exogenous VZV
infection, while herpes zoster represents
reactivation of an endogenous VZV
infection, which persists in a latent form in
the sensory neurons following an earlier
• Both conditions are usually benign and self-
limiting in patients with normal immuno-
• One attack of varicella in childhood gives life
long immunity to the patient.
• The incubation period is usually 14-17 days.
• Varicella occurs throughout the world, the
highest incidence occurs in children aged
• In tropical and semitropical countries,
infection is delayed and varicella is seen more
often in adults. Subclinical infection may
• On the other hand, zoster is uncommon in
childhood and the incidence increases with
• In patients with impaired immunity, both the
incidence and severity of zoster are increased,
and it is frequently complicated by dissemi-
nated cutaneous disease and systemic
involvement, usually pneumonia, hepatitis,
Fig. 7.19: Chicken pox—vesicular eruption over the
trunk in different stages of evolution in an adult patient
Viral Infections 53
• In patients infected with HIV, zoster is 10
times more common than in normal
population and may become disseminated
• In older children and adults, the rash is often
preceded by 2 to 3 days of fever, chills,
malaise, headache, anorexia, severe backache
and in some patients, sore throat and dry
• The rash of varicella begins on the face and
scalp and spreads rapidly to the trunk (Fig.
7.19) with relative sparing of the extremities.
• New lesions appear in successive crops but
their distribution remains centripetal.
• The lesion starts as a 2 to 4 mm red papule,
which develops an irregular outline (rose
petal) as a thin-walled clear vesicle appears
on the surface (dew drop). This lesion, “dew
drop on a rose petal” is highly characteristic
(Fig. 7.20). The vesicles become umbilicated
and pustular, rupture to form crusted lesions.
• A distinctive feature of varicella is the
simultaneous presence of skin lesions in all
stages of evolution in any one area of the
• The most common complication is the
secondary bacterial infection of skin lesions
usually by staphylococci or streptococci and
may be prolonged by scarring. Other notable
complications are primary varicella pneu-
monia, Reye’s syndrome, acute cerebellar
ataxia, encephalitis, and disseminated
varicella in immunosuppressed.
• Maternal varicella during the early months
of pregnancy can lead to ‘congenital varicella
syndrome’, which manifests as extensive
cutaneous scarring, muscular atrophy, limb
hypoplasia, rudimentary digits, chorio-
retinitis and cortical atrophy.
Differential Diagnosis of Varicella
• Disseminated herpes simplex: Has
concentration of lesions at and surrounding
the site of the primary infection and there is
associated marked toxicity and encephalitis.
• Eczema herpeticum: Vesicles develop over
the areas of active or recently healed atopic
dermatitis. The lesions are particularly
distributed on the face. Patients commonly
have high fever and adenopathy.
• The word ‘Shingles’ is derived from the Latin
‘singulus’ a girdle that refers to the segmental
arrangement of the eruption.
Fig. 7. 20: Chicken pox—dew drops on rose petals
Fig. 7. 21: Herpes zoster—grouped vesicles on
erythematous patches in thoracic dermatome
Essentials in Dermatology54
Fig. 7. 22: Herpes zoster—grouped vesicles on
genitalia in a male
Fig. 7. 23: Herpes zoster ophthalmicus—unilateral
involvement of forehead and scalp by herpes zoster
• Zoster afflicts 20% of the general population,
during their life times, especially the elderly.
• More than two thirds of the reported cases
occur in individuals over fifty years of age
and less than ten percent occur in those
under the age of twenty years.
• The first symptoms are usually pain and
paraesthesia in the involved dermatome. This
often precedes the eruption by several days
and varies from superficial itching, tingling,
burning or lancinating pain.
• The rash is nearly always unilateral.
• It begins as closely grouped maculopapules,
which rapidly become vesicular in 12-24
hours (Figs 7.21 and 7.22) and then pustular
in 2 to 3 days. The lymph nodes draining that
area become enlarged and tender. The lesions
dry up and crust in 7 to 10 days. Recovery
takes about 3 to 4 weeks or longer in older
• The thoracic (53%), cervical (20%),
trigeminal, including ophthalmic (18%)
(Fig. 7.23) and lumbosacral (11%)
dermatomes are most commonly involved
at all ages, but the relative frequency of
ophthalmic zoster increases in old age.
• Hutchinson’s sign: Vesicles on the side or on
the tip of the nose that occur during episode
of ophthalmic zoster are usually associated
with serious ocular complications.
• Complications of herpes zoster are
hypopigmented or hyperpigmented scars,
post herpetic neuralgia (usually defined as
‘chronic segmental pain’ appearing or
persisting 3 months after cutaneous zoster
healing), post herpetic anesthesia, recurrent
zoster, motor neuron involvement (motor
weakness usually follows the pain and
eruption by a few days to weeks), ocular
complications (superficial and deep keratitis,
corneal ulcerations, panophthalmitis, ocular
palsies, neuralgia, retinal vasculitis and optic
neuritis), and rare complications include
meningitis, pneumonitis, and myelitis.
• Post herpetic neuralgia- Overall incidence
is 8 to 15% and risk factors are old age, severe
Viral Infections 55
pain during acute phase, presence of
prodromal pain, greater rash severity, and
delay in starting treatment.
• In HIV infected patients, herpes zoster
ophthalmicus (HZO) is associated with
several severe complications and may the
initial manifestation of AIDS. Cutaneous
lesions can be unidermatomal, multi-
dermatomal (Fig. 7.24), disseminated or
chronic and ulcerative.
Differential diagnosis: Zosteriform herpes
simplex- Vesicles vary in size in zoster, in
contrast to uniformly sized vesicles in herper
simplex and a history of multiple recurrences at
the same site in herpes simplex.
• Tzanck smears of cutaneous lesions of
varicella and zoster show multinucleated
giant cells and epithelial cells with typical
acidophilic intra-nuclear inclusions similar
to those seen in herpes simplex.
Fig. 7.24: Herpes zoster—zoster occurring in
• Skin biopsy of lesions also shows histological
changes similar to those found in herpes
• Definitive diagnosis accomplished by the
isolation of virus in cell cultures and electron
• Identification of VZV antigens in cutaneous
lesions and PCR for detection of nucleic acids
in clinical specimen are the alternative
methods of diagnosis.
• Symptomatic treatment is given in otherwise
healthy patients. Rest and analgesics are
• Acyclovir is given in severe varicella and
zoster (ophthalmic herpes zoster, Ramsay
Hunt syndrome) and also in those patients
who are at high risk of disseminated infection
(more than 50 years of age, immuno-
suppressed patients). Acyclovir 800 mg 5
times a day for 7 to 10 days (in children dose
is 20 mg per kg body weight four times daily).
• Alternative antiviral drugs are famciclovir
(500 mg three times daily), valacyclovir (1
gm three times daily) and foscarnet in
acyclovir resistant cases.
• Valacyclovir is contraindicated in
immunosuppressed individuals. Thrombotic
thrombocytopenic purpura and hemolytic
uremic syndrome have occurred in patients
with AIDS, renal transplant and bone
• For post herpetic neuralgia-topical therapy
(capsaicin, aspirin, lignocaine), nerve blocks,
and systemic therapy (systemic steroids,
carbamazepine, valproate, tricyclic
antidepressants) may be tried. Gabapentin is
the drug of choice now. Initial dose of 300
mg/day is increased over 4 weeks (up to 3600
mg/day divided into three divided doses)
until efficacy obtained or side effects
Essentials in Dermatology56
• Live attenuated viral vaccine for varicella can
be used in healthy children as a prophylaxis.
Its efficacy persists for 10 years.
• Varicella zoster immunoglobin therapy is
indicated in those who are high risk patients,
to prevent or modify varicella in them.
KAPOSI’S VARICELLIFORM ERUPTION
• It is a special form of widespread cutaneous
viral infection occurring in a patient with pre-
existing skin disease.
• Atopic eczema is the most common
• Other susceptible dermatoses include
Darier’s disease, pemphigus foliaceous,
ichthyosis vulgaris, mycosis fungoides and
allergic contact dermatitis (Fig. 7.17).
• Majority of cases are due to infections with
herpes simplex virus – called eczema
• Less commonly occur with other viruses like
Coxsackie A 16 and vaccinia (eczema
vaccinatum- no more seen).
• Clinically presents with clusters of
umbilicated vesicles in areas where the skin
has been previously abnormal.
• They may be associated with fever and other
constitutional features. The face is usually
severely affected and may be edematous.
• The evolved pustules become crusted and
heal with permanent scarring in 2-6 weeks.
• Multinucleated epithelial giant cells are seen
in Tzanck smear.
• Treated with antiviral such as acyclovir
where infection is due to herpes simplex
KAWASAKI DISEASE (KD)
KD is an acute multisystem vasculitis of
unknown etiology. It was first described in Japan
by Kawasaki (1967).
CDC diagnostic criteria:
Fever lasting longer than 5 days plus at least four
of the following:
1. Bilateral conjunctival injection.
2. Mucous membrane changes (1 or more): Red
or fissured lips, red pharynx, ‘strawberry’
3. Extremity changes (1 or more): Erythema of
palms or soles, edema of hands or feet,
desquamation (generalized or periungual)
4. Rash-erythematous exanthema.
5. Cervical lymphadenopathy (at least 1 node
larger than 1.5 cm).
• Death in KD occurs due to cardiac
• Treatment: aspirin, intravenous gamma-
Fungal Infections 57
Fungi are aerobic organisms that form a cell wall
and grow on or in organic material, forming a
colony and reproducing either sexually or
asexually. In contrast to plants, fungi do not
including human beings. Fungi are also essential
part of the ecologic cycle and also of considerable
benefit to man as a source of antibiotics, in baking
and in beer brewing.
Fungal infections of skin may be divided into
superficial and deep.
Superficial fungal infections
DERMATOPHYTE INFECTIONS (TINEA,
• Causative agent: The dermatophyte (or
ringworm). Three species of dermatophytes
1. Trichophyton (affects skin, hair and nails)
2. Microsporum (affects skin and hair)
3. Epidermophyton (affects skin and nails)
Humans acquire infection from three sources—
soil, animal or humans
• Dermatophyte fungi grow only within keratin
layers, do not invade living epidermis
8 Fungal Infections
• Predisposing factors—Tropical climate of heat
and humidity, poor nutrition and hygiene,
debilitating diseases including HIV infection
• It occurs at any age except tinea capitis which
occurs in children mainly.
• Most common dermatophyte incriminated is
Tinea corporis—infection of the non-hairy skin
of trunk and limbs
• The typical lesions start as itchy erythematous
macule or papules that spread outward and
develop into annular (ring like) and arciform
lesions with sharp, scaling or papulovesicular
advancing margin and healing centers (Figs
8.1 and 8.2)
• A variant of tinea corporis called tinea
imbricata (imbricata is Latin for tiled) caused
by Trichophyton concentricum, is
characterized by large concentric rings, one
inside another, which manifest commonly in
• Other variants.
1. Majocchi’s granuloma–characterized by
perifollicular granulomatous nodules on
the scalps of children, often without
2. Agminate folliculitis- characterized by
well defined erythematous plaques
Essentials in Dermatology58
studded with perifollicular pustules
caused by zoophilic organism.
• Differential diagnosis: A. For annular lesions
are nummular eczema (does not have an
advancing border, lacks central clearing),
granuloma annulare (no scaling, presence of
skin colored intradermal papules) and
erythema annulare centrifugum (have scales
at the trailing edge of the advancing border
instead of over the entire border). B. For
papulosquamous lesions are psoriasis (well
defined erythematous plaques, scales are
silvery white micacaceous and reveal
bleeding points when removed positive
‘Auspitz sign’, lesions typically involve
extensor extremities, scalp and sacrum),
pityriasis rosea (papular or annular, oval
multiple lesions have characteristic
distribution pattern over the trunk, individual
lesions have a collarette of scales, scale does
this acute eruption, has self limited course).
• Most common in the tropics (Fig. 8.3).
• Differential diagnosis are candidiasis (more
often involves concavities of the flexures and
produces macerated, moist, glazed, erythe-
matous plaques with satellite pustules and it
more often involves the scrotum), inverse
psoriasis (tends to be asymptomatic, well-
defined erythematous plaque), and eryth-
rasma (lacks a scaling border and
inflammation, asymptomatic in nature,
fluoresces coral red under a wood light).
Fig. 8.1: Tinea corporis–typical annular
erythematous ring like lesions of tinea corporis
Fig. 8.2: Tinea corporis–multiple ring like lesions
over the trunk
Fig. 8.3: Tinea cruris–marked hyperpigmentation
with active border showing erythematous papules
Fungal Infections 59
Tinea barbae-ringworm of the beard and
Tinea faciei-ringworm of the face- most often
misdiagnosed (Fig. 8.4).
Tinea capitis- ringworm of the scalp,
transmitted from child to child, most
commonly caused by Trichophyton violaceum.
cause endothrix infection (arthroconidia of
dermatophytes contained within the hair
shaft) of hair. Less frequently, ectothrix
infection (arthroconidia of dermatophytes
surrounding the hair shaft as a sheath) of hair
• Patchy hair loss and broken hairs,
inflammation and scaling are characteristic
of (back dot (Fig. 8.5), grey patch (Fig. 8.6),
seborrheic dermatitis like) tinea capitis.
• Kerion is caused by zoophilic fungi–
Trichophyton verrucosum and Trichophyton
mentagrophyte. Typically, it produces a boggy
painful inflammatory swelling studded with
exudative follicular pustules, hair fallen off
or easily pluckable (Fig. 8.7).
• Favus in India occurs mainly in Kashmir and
is caused by Trichophyton schonleinii. On the
scalp, concave sulfur-yellow crust (called
scutulae) form around loose wiry hairs. It
heals with thin smooth atrophic scarring.
Differential diagnosis are alopecia areata
(patchy non-scarring alopecia, presence of
exclamation mark hair, non-scaly condition),
trichotillomania (irregular patchy hair loss from
an approachable site because of hair pull trauma,
so hairs are of different lengths), seborrheic
dermatitis (greasy scaling is more diffuse, with
erythema, changes confined to scalp and other
Fig. 8.4: Tinea faciei–erythematous scaly annular
lesion over the face
Fig. 8.5: Tinea capitis–patchy hair loss with black
dots “Black dot” type
Fig. 8.6: Tinea capitis–partial loss of hair, remaining
hair in the alopecia patch area are luster less “Grey
Essentials in Dermatology60
seborrheic areas of the body, generally no hair
loss), and bacterial pyodermas of scalp (loss of
hair is minimal, plucking of hair may be difficult
• Interdigital type-interdigital scaling and
maceration with fissures is the most common
form (Fig. 8.8).
• Chronic hyperkeratotic type or Moccasin foot-
widespread scaling extends onto the sides of
• Vesicular or bullous type due to some
• Acute ulceratic type
Differential diagnosis: For the interdigital type are
erythrasma (very well defined lesion, it has
whitish appearance usually asymptomatic and
rarely causes fissures) and candidiasis (increased
severity of maceration, denudation and pruritus).
from palmoplantar psoriasis, palmoplantar
dermatitis may also be considered although it
affects the dorsum of foot than plantar aspect
The vesicobullous type may be confused with
pustular psoriasis, palmoplantar pustulosis, and
Tinea manuum-ringworm of the hands
• Usually seen as mild erythema with
hyperkeratosis and scaling, mainly over the
palmar surfaces (Fig. 8.9).
• Unilateral scaling with onychomycosis if
present should always be scraped for fungus
• Contact dermatitis, psoriasis, and hyper-
keratotic eczema must be considered as
Tinea unguium- fungal infections of the nails
borders of the nails, as yellow discoloration
and progress proximally (distal and lateral
Fig. 8.7: Tinea capitis–boggy inflammatory swelling
over the scalp “Kerion” type
Fig. 8.8: Tinea pedis–scaly hyperkeratotic lesion on
the sole of one foot, other normal for comparison
Fungal Infections 61
• The nails become brittle, friable, and
thickened (Fig. 8.11).
• Four distinct patterns of tinea unguium are
distal and lateral subungual onychomycosis
(most common pattern), superficial white
onychomycosis, proximal subungual
onychomycosis (associated with HIV/AIDS
cases), and endonyx onychomycosis (nail
infection caused by dermatophytes that cause
endothrix scalp infection characterized by
scarred nail plate with pits and lamellar
• Ringworm of the nails is rarely symmetrical
and it is common to find the nails of only one
• Differential diagnosis is psoriasis (coarse
pitting of dorsal nail plate is never produced
by fungal infection, and strongly suggests
psoriasis, as does the oil drop sign from the
free edge), eczema (irregularly buckled nails)
and lichen planus (ridged or dystrophic nails)
Tinea incognito- ringworm infections
modified by corticosteroids, systemic or topical,
prescribed for some pre-existing pathology or
given mistakenly for the treatment of
misdiagnosed tinea (Fig. 8.12).
• KOH mount– definitive diagnosis is made by
the microscopic examination and identi-
fication of hyphae and spores in scales
(Fig. 8.13) or hair. In nails, the presence of
hyphae usually means dermatophyte
infection, rarely saprophytic fungi infection.
• Cellophane tape examination and staining
with periodic acid Schiff’s (PAS) reagent of
Fig. 8.9: Tinea manuum–unilateral scaly lesions of
Fig. 8.10: Tinea manuum with tinea unguium
Fig. 8.11: Tinea unguium–thickening and
dystrophy of involved nails
Essentials in Dermatology62
the material taken from skin (Fig. 8.14), hair
and nails can be studied.
• Confirmed by culture on Sabouraud’s media.
• Histological examination of nails with special
stain-Periodic Acid Schiff’s stain.
• Topical therapy- indicated for infections of
the body and groin and superficial
involvement of the beard region, palms, and
Topical agents used are—
1. Whitfield ointment (contains 6% benzoic acid
and 3% salicylic acid)
2. Imidazole derivatives – miconazole (2%),
clotrimazole (1%), econazole (1%),
ketoconazole (2%), oxiconazole, sulconazole,
3. Ciclopirox olamine
4. Undecylenic acid
5. Tolnaftate 1%
6. Azelaic acid
7. Castellani’s paint
8. Terbinafine (1%)
Duration of therapy is 4 to 6 weeks or 2 weeks
more after clearance of lesions.
nail infection and in those cases where tinea
is extensive, widespread and non-responsive
to topical therapy. Griseofulvin (10-20 mg per
kg body weight or 250 mg twice a day),
ketoconazole (200 mg daily), itraconazole (200
mg daily or one week pulse of 400 mg daily
for 2 to 3 months), fluconazole (6 to 8 mg per
kg body weight daily or 150 mg, 300 mg or
450 mg per week for 3 to 6 months) and
terbinafine (250 mg daily or 250 mg twice a
day) are the drugs used systemically. The skin
and hair infection require shorter course of
therapy (6-8 weeks therapy with griseofulvin)
whereas nail infection require longer therapy
(9-12 months with griseofulvin).
Fig. 8.13: KOH mount–showing branching
Fig. 8.12: Tinea incognito–erythematous papular
eruption of tinea due to immunosuppression
Fig. 8.14: Periodic Acid Schiff’s (PAS) stained smear
showing septate branching hyphae–dermatophytes
Fungal Infections 63
TINEA VERSICOLOR (PITYRIASIS
• It was thought that a single polymorphic yeast
Pityrosporum ovale, or two species P. ovale
and P. orbiculare, were the causative agents,
but it is now recognized that this genus was
invalid. There are at least 7 separate species
of lipophilic yeast- Malassezia on the human
skin: M-sympodialis (most commonly found on
the normal skin), M.globosa (most frequently
associated with tinea versicolor), M. restricta,
M. dermatis, M.slooffiae, M.obtusa and M. furfur.
• Predisposing factors- Warm and humid
climate of tropics, pregnancy, serious
underlying diseases, immunocompromised
host, Cushing’s syndrome, malnutrition.
• The term “versicolor” refers to the presence of
both hyper-and hypopigmented lesions
• A peculiar aspect of tinea versicolor is its
or hyperpigmented, finely scaling, round or
perifollicular coalescing macular patches
found primarily over the trunk (Figs 8.15 and
8.16). The hypopigmentation is explained on
the basis of dicarboxylic acids produced by
Malassezia species (e.g., azelaic acid) causing
competitive inhibition of tyrosinase and
perhaps a direct cytotoxic effect on
hyperactive melanocytes. The hyperpig-
mentation may be due to abnormally large
melanosomes and thicker keratin layer. To
elicit fine branny powdery scales, candle
grease sign or coup d’ongle sign is elicited.
• The eruption is almost always asymptomatic
and only of cosmetic significance
• Other cutaneous disorders associated with
Malassezia yeasts are seborrhoeic dermatitis,
Malassezia folliculitis, Confluent and
reticulate papillomatosis, and sebopsoriasis.
• KOH preparation-reveals numerous short,
straight and angular hyphae and clusters of
thick walled round and budding yeasts
“Spaghetti and meat ball appearance” or
“Banana and grapes appearance”(Fig. 8.17).
• Cellophane tape examination and staining
with periodic acid Schiff’s (PAS) reagent and
India ink of the material taken from skin (Figs
8.18 and 8.19).
Fig. 8.15: Tinea versicolor–hypopigmented
macules with fine powdery scales
Fig. 8.16: Tinea versicolor–hyperpigmented
macules with fine scaling
Essentials in Dermatology64
• Culture- Sabouraud’s dextrose agar overlaid
with sterile olive oil or lanolin. Antibiotics
such as penicillin, streptomycin and
cycloheximide are incorporated to reduce
growth of contaminants.
• Wood’s light examination-golden to orange
1. Pityriasis alba– characterized by poorly
marginated, hypopigmented, slightly scaly
patches on the cheeks of young children.
2. Indeterminate leprosy– usually seen in
children with one or more macules,
hypopigmented to faintly erythematous with
an ill-defined to well defined edge. Lesions
may be on the face or the limbs. Slight
anaesthesia may be demonstrable.
3. Vitiligo– characterized by depigmented
macules without any scaling
4. Erythrasma– Hyperpigmented tinea versi-
color can be confused with erythrasma, but
satellite lesions are less common in
erythrasma and there is coral red fluorescence
under Wood’s lamp.
5. Seborrhoeic dermatitis– May occur in areas of
tinea versicolor distribution, but patches have
an erythematous yellowish tint and scales are
soft and greasy
– Topical– Selenium sulfide suspension (2.5%),
zinc pyrithione, ketoconazole (2%) shampoo,
sodium hyposulfite (25%), propylene glycol
and imidazole derivatives are used topically.
– Systemic– Ketoconazole (200 mg daily for 5 to
10 days), itraconazole (200 mg daily for 5 to 7
days) or fluconazole (single oral dose of 400
mg) are effective systemically.
Fig. 8.17: KOH mount–clusters of spores with short
mycelial filaments. “Spaghetti and meat ball”
Fig. 8.18: Periodic Acid Schiff’s (PAS) stained smear
showing cluster of spores with short stumpy mycelial
Fig. 8.19: Parker ink staining of hyphae and spores
of tinea versicolor
Fungal Infections 65
– Causative agent–Candida albicans. This
yeast like fungus is normally found on the
mucous membranes, skin, in the gastro-
intestinal tract and in the vagina. Under
certain circumstances, it changes from a
commensal organism to a pathogen. Apart
from Candida albicans, few other species of
Candida like C. tropicalis, C. dubliniensis, C.
parapsilosis, C. guilliermondii, C. krusei, C.
glabrata may be involved
– Predisposing factors– Local factors are
moisture, warmth, maceration, and/or
occlusion and systemic factors are antibiotics
therapy, corticosteroids, oral contraceptive
pills, pregnancy, diabetes, immunocom-
promised state including HIV infection.
• Oral thrush– It presents as curdy, white, easily
detachable deposits on tongue or oral mucosa
with underlying bright red and moist surface
(Figs 8.20 and 8.21). This form of candidiasis
is also known as acute pseudomembranous
candidiasis. Other forms of oral candidias is
include acute and chronic atrophic
candidiasis, chronic hyperplastic candidiasis,
and median rhomboid glossitis. Oral thrush
can be confused with coated tongue due to
dehydration, mucositis due to chemo-
therapeutic drugs, aphthous ulcerations,
herpetic infections, oral hairy leukoplakia,
erythema multiforme, pemphigus, lichen
planus, discoid lupus erythematosus,
Pernicious anemia, histoplasmosis, leuko-
plakia, secondary syphilis.
• Perleche–sore angles of mouth.
• Intertriginous type– Well-defined peeling
border around moist red macerated lesions
and surrounded by satellite papules or
pustules- occur in body folds such as groin,
inframammary, axillary, perianal and
interdigital areas (Fig. 8.22). Differential
Fig. 8.20: Oral candidiasis–curdy white deposits on
the hard palate in a baby
Fig. 8.21: Oral candidiasis with angular cheilitis in
a HIV adult case
Fig. 8.22: Intertriginous candidiasis–toe cleft
showing moist macerated lesion
Essentials in Dermatology66
diagnosis includes tinea cruris, seborrhoeic
dermatitis, flexural psoriasis and bacterial
• Paronychia– inflammatory boggy swelling of
posterior and lateral nail folds of digits of
fingers (Fig. 8.23), commonly seen in house
wives, maidservants, due to continuous wet
• Vulvovaginitis-frequently associated with
itching and vaginal discharge. The vaginal
mucosa shows erythema, edema and curdy
white deposits (Fig. 8.24). Candidal balano-
posthitis occurs as a counter part in males
• KOH preparation-reveal budding yeasts with
or without hyphae or pseudohyphae.
• Gram’s stained smear-gram positive
organisms longer than bacteria.
• Confirmed by culture on Sabouraud’s media.
Whitish mucoid colonies grow within 2 to 5
• Evaluation and treatment of underlying
• Nystatin, imidazoles and broad-spectrum
triazoles are the agents of greatest use in the
treatment of candidal infection. Gentian violet
and Castellani’s paint are older effective
• Potassium permanganate soaks are more
effective in moist Candidal intertrigo.
• Recurrent or recalcitrant infections require
oral medication with nystatin (to rid the gut
and vagina of candida organisms),
fluconazole (50 mg daily for 14 days),
ketoconazole (200 mg daily) or itraconazole
(200 mg daily).
• For vaginal candidiasis, 500 mg clotrimazole
vaginal tablet once or 200 mg miconazole
tablet at bed time for 3 days or single oral dose
Fig. 8.23: Chronic paronychia–swelling of proximal
and lateral folds of many fingers with nail changes
Fig. 8.24: Candidal vulvovaginitis–vulval erythema
with white deposits
Fig. 8.25: Candidal balanoposthitis–glazed
erythema with pustulation over glans and prepuce
Fungal Infections 67
of 150 mg of fluconazole or twice daily dose of
itraconazole (200 mg twice a day).
• It is a rare syndrome which is characterized
by recurrent and persistent candidal infection
of skin, nail and mucous membrane. It has
autosomal dominant or recessive inheritance.
Several endocrinopathies (e.g. hypothyro-
idism, hypoadrenatism, etc.) may be
• Treatment: Treatment of this condition
depends critically on systemic antifungal
chemotherapy. Attempts have been made to
restore T cell function, by the use of transfer
factor, or thymosin, or grafting compatible T
lymphocytes and non specific measures like
the restoration of normal iron stores.
Prolonged and repeated use of systemic
antifungals like fluconazole, itraconazole and
ketoconazole may be necessary.
• Causative agent- Phaeoannellomyces werneckii
(syn. Exophiala werneckii), a mould which
produces a melanin like pigment.
• This characteristic disorder manifests as one
or several brown or black spots that resemble
silver nitrate or India ink stains.
• Most frequently lesions occur on the palms
but also on the soles.
• The fungus can be easily demonstrated by
KOH examination and culture.
• Differential diagnosis are junctional naevi,
melanoma, Addison’s disease, and chemical
stains, however, tinea nigra can be easily
differentiated by doing a KOH examination
which shows brown coloured hyphae and
spindle shaped yeast cells.
• Topical imidazoles such as clotrimazole,
miconazole, ketoconazole, etc. are effective.
PIEDRA (PIEDRA = STONE)
• Causative agent-
– White piedra-Trichosporon beigelii
(Trichosporon cutaneum), a yeast seen in
– Black piedra-Piedra hortae, a mould, occurs
mostly in the tropics
• Pinhead sized, hard nodes occurs on the hairs
of the scalp, brows, lashes, or beard
• KOH examination and culture clinch the
• Differential diagnosis– Nits, hair casts,
developmental hair defects and trichomycosis
axillaris may be differentiated by doing a
• Treatment is by cutting hair. Oral terbinafine
250 mg daily for 6 weeks has been shown to
be effective against black piedra. For white
piedra, imidazoles, selenium sulfide, zinc
pyrithione, etc. are effective agents.
Deep fungal infections
• Mycetoma is a deep fungal infection,
characterized by a clinical triad of swelling,
discharging sinuses and discharge
containing granules (Figs 8.26 and 8.27). It
commonly occurs on the foot, hence also
called as Madura foot.
• Mycetoma-caused by species of fungi is
known as eumycetoma, and that caused by
aerobic actinomycetes or filamentous
bacteria as actinomycetoma.
Type of mycetoma Causative organisms
Eumycetoma Madurella mycetomatis
Actinomycetoma Actinomadura madurae
Essentials in Dermatology68
• The organisms are usually soil or plant
saprophytes that are only incidental human
• KOH examination, Gram’s staining,
histopathology of lesion and culture helps in
confirmation of the diagnosis.
• Differential diagnosis
1. Chronic osteomyelitis of bacterial or
tuberculosis origin (characteristic grains
are not discharged)
2. Elephantiasis (no sinus tracts)
3. Primary cutaneous actinomycosis
(develops on the exposed sites, very rare
type of actinomycosis, caused by Actino-
myces isralei, a normal inhabitant of
human mouth, thus it is an endogenous
• Actinomycetomas generally respond to
antibiotics such as a combination of dapsone
with streptomycin or sulfamethoxazole-
trimethoprim plus rifampin or streptomycin.
Amikacin may also be used in recalcitrant
• Of the fungal causes of mycetoma,
M. mycetomatis may respond to ketoconazole
(200 mg daily over several months). For the
others, a trial of therapy with griseofulvin or
itraconazole is worth attempting. Surgery,
usually amputation, is the definitive
procedure and may have to be used in
• Chromoblastomycosis is primarily a disease
of tropical or subtropical regions.
• At least five distinct organisms are well
known to cause chromoblastomycosis:
Fonsecaea pedrosoi, Fonsecaea compactum,
Cladosporium carrionii, Phialophora verrucosa,
and Rhinocladelia (Acrotheca) aquaspersa.
• The characteristic feature of a well-developed
lesion is a pruritic warty plaque of the
extremities in an agricultural worker, which
drains purulent material (Fig. 8.28).
• The pathology of chromoblastomycosis
consists of striking epidermal thickening
(pseudoepitheliomatous hyperplasia) over-
Fig. 8.26: Mycetoma–a triad of features – swelling,
discharging sinuses and discharge containing
granules seen commonly over the foot
Fig. 8.27: Mycetoma over the upper back
Fungal Infections 69
lying a suppurative granulomatous
dermatitis. At least three appellations are
frequently used to designate the tissue form of
these fungi: Medlar bodies, sclerotic bodies,
muriform bodies or the descriptive “copper
• Differential diagnosis:
1. Blastomycosis (presence of sharp border
with minute abscesses and by the presence
of pulmonary lesions)
2. Cutaneous tuberculosis and leish-
maniasis (biopsy and culture will
establish the diagnosis)
3. Elephantiasis verrucosa nostras (mossy
• The known treatments may be divided into
three groups: surgery, physical modalities
(heat, cryotherapy, electrosurgery, and
radiation therapy), and systemic antifungal
triazole derivatives especially itraconazole,
• Rhinosporidiosis is a chronic granulomatous
mycosis caused by Rhinosporidium seeberi.
• It is seen most often in southern India and
• It is more common in adult males and is
possibly transmitted to man by direct contact
with spores through dust, infected clothing
or fingers and swimming in stagnant waters.
• Rhinosporidiosis frequently involves the
nasopharynx (70%) presenting as a painless,
friable, polypoidal growth, which may hang,
anteriorly from the nares (Fig. 8.29) or
posteriorly into the pharynx. The lesions are
pink or purple red and studded with minute
white spots which are the sporangia
containing spores. Nasal obstruction and
conjunctiva and lacrimal sac are involved in
15% of cases.
• Occasionally, it affects the lips, palate, uvula,
maxillary antrum, epiglottis, larynx, trachea,
bronchus, ear, scalp, vulva, vagina, penis,
rectum or the skin (Figs 8.30 and 8.31).
• Since the causative agent cannot be cultured,
the diagnosis can be confirmed by
demonstrating typical sporangia and spores
in histopathology and imprint smears.
• Differential diagnosis is nasal polyps, warts,
Fig. 8.28: Chromomycosis–verrucous itchy plaque
lesion over the dorsa of the hand
Fig. 8.29: Rhinosporidiosis–pink friable polypoidal
growth projecting from the nares
Essentials in Dermatology70
• Surgical removal and electro desiccation are
the treatments of choice.
• Subcutaneous zygomycosis or subcutaneous
phycomycosis (SP) has two clinically and
mycologically distinctive entities termed as
basidiobolomycosis (etiological agent:
Basidiobolus ranarum) and conidio-
bolomycosis (etiological agent: Conidiobolus
Fig. 8.30: Rhinosporidiosis–pink friable polypoidal
growth over the root of the nose
Fig. 8.31: Rhinosporidiosis–noduloplaque lesions
over the arms
coronatus). These organisms belonging to
Entomophthorales cause granulomatous
infection that usually affects healthy people.
• SP due to Conidiobolus is uncommon.
Clinically, the disease is characterized by
nasal obstruction due to the inflammation of
the submucosa of the nostril, usually in the
vicinity of the inferior turbinate.
• SP is also caused by Basidiobolus. The site of
infection is usually confined to the limb
girdles or proximal limbs. It occurs chiefly in
children. Characteristically, it manifests as
painless, well-circumscribed, firm to hard
subcutaneous masses, which grow slowly at
the periphery and may envelop parts of or a
whole limb (Fig. 8.32). The border is smooth,
rounded, clearly defined, and can be raised
up by inserting fingers underneath it. This is
thought to be an almost diagnostic clinical
feature of the disease. There is no involvement
of the regional lymph nodes.
Fig. 8.32: Subcutaneous phycomycosis–shiny disk
like indurated lesion over the thigh, can be insinuated
at the margin with fingers
Fungal Infections 71
• Differential diagnosis:
1. Lymphatic edema (no distinctive edge)
2. Subcutaneous malignant lymphoma
(grows more rapidly)
3. Subcutaneous morphea
• A therapeutic trial with potassium iodide in
a clinical setting may be considered as an
important criterion for diagnosis where
facilities to culture the organism do not exist.
• It is caused by Sporothrix schenckii and is
characterized by nodulo-ulcerative and
crusted lesions arranged in a linear fashion
over the extremities with intervening
lymphatics thickened like a cord.
• The best sources of diagnostic material are
smears, exudates, and biopsies (to look for
“Asteroid bodies”). S. schenckii is very rarely
seen in direct microscopic examination
because yeasts are usually present only in
small numbers; the organism can be readily
isolated on Sabouraud’s agar.
• Differential diagnosis:
1. Fish tank granuloma
2. Cutaneous leishmaniasis
• Potassium iodide (saturated solution) is
effective in the cutaneous types of
Other deep fungal infections: Cryptococcosis
and aspergillosis are ubiquitous throughout the
world. In south east Asia, penicillinosis is
common whereas coccidioidomycosis and
histoplasmosis are restricted to certain
• Cryptococcosis is an opportunistic infection
caused by the encapsulated yeast Cryptococcus
• Virtually all infections involve the central
nervous system, with meningitis the most
• Cutaneous dissemination occurs in 10% to
20% of patients, has a variable presentation
and may precede other signs of infection.
• Initial signs of cryptococcosis include
cellulitis, genital or oral ulcerations, or
molluscum-, herpes simplex-, or Kaposi’s
sarcoma- like lesions.
• Diagnosis can be made by performing
curettage on a lesion, by making a potassium
hydroxide preparation, India ink
preparation, isolation of fungus on culture or
by a biopsy of lesion. Cryptococcal antigen is
present in these patient sera and can be
detected by latex particle agglutination.
• Intravenous amphotericin B alone or with
flucytosine and oral fluconazole is highly
effective in the treatment of cryptococcus
• Penicillium marneffei is the only penicillium
species that is dimorphic and can cause
systemic mycosis in human beings,
particularly those who are immuno-
• Features of the infection frequently include
fever, anemia, marked weight loss, cough and
diarrhea, but skin eruptions occur in the
• Cutaneous manifestations usually consist of
a generalised papular eruption, in which the
papules may be umbilicated (due to central
folliculitis, macular rash and mouth ulcer
have also been reported.
• Diagnosis depends on isolation of the
organism from blood or tissue.
• Treatment includes systemic amphotericin B,
itraconazole or fluconazole.
Essentials in Dermatology72
SCABIES (THE ITCH,
SEVEN YEAR ITCH)
• Causative agent: Sarcoptes scabiei var. hominis
• Morphology: The mite has an ovoid body,
flattened dorsoventrally. The body is creamy
white marked with transverse corrugations,
and on its dorsal surface by bristles and
spines (denticles). The mite has four pairs of
short legs. The rear two pairs of legs of female
mites end in long bristles called setae. Adult
female mite measures about 0.4 × 0.3 mm
whereas adult male about 0.2 × 0.15 mm. The
mite prefers non-hairy skin and areas of low
• Life cycle: Copulation occurs in burrows
excavated by female mite in stratum
corneum. After copulation, the pregnant
female enlarges the burrows and begins egg
laying. It travels 5 mm per day and lays 40-
50 eggs during its life span of 4-6 weeks (Figs
9.2 and 9.3). These eggs hatch in a week and
reach maturity (eggs-larvae-nymph-adult) in
about 3 weeks.
• Most infected adults harbor 10 to 12 mites
• Mode of spread-close personal contact, but
may be transmitted through clothing, or
• Incubation period- when a human is
infested for the first time, symptoms usually
Fig. 9.1: Sarcoptes scabiei mite (300-400 microns) Fig. 9.2: Eggs and fecal pellets of sarcoptes
develop after 3-6 weeks while after
reinfestation, they occur within 1 or 2 days.
• The classic symptom is intense pruritus
especially at night in bed
• The sites of predilection are the interdigital
spaces (Fig. 9.4), wrists, points of elbows,
antecubital fossae, the anterior axillary folds,
the umbilicus (Fig. 9.5), and the genitalia (Fig.
9.6) especially the gluteal cleft (Fig. 9.7)
(“circle of Hebra”).
• The most diagnostic or pathognomonic
finding is an intact “S” shaped or linear
burrow with a papule or vesicle at its end
housing the mite (Fig. 9.8). Most common
Fig. 9.4: Scabies – typical finger web spaces
involvement with papular, vesicular and crusted
Fig. 9.5: Scabies – periumbilical papular lesions
Fig. 9.6: Scabies – genital and thigh area involved
by papular and excoriated lesions
Fig. 9.7: Scabies – papular lesions over the gluteal
Fig. 9.3: An egg of sarcoptes
Essentials in Dermatology74
sites are webspaces of the hands, wrists, and
lateral aspect of palms.
• Generalized urticarial papules, excoriations
and eczematous changes are secondary
lesions caused by sensitization to the mite.
• Tiny scaly papules on the nipple and male
genitalia (glans, shaft and scrotum) are
pathognomonic of scabies.
• Infants and small children often have
vesicular lesions on the palms, soles, head
and neck (Figs. 9.9 and 9.10). Scabies in
babies is generally more extensive in
distribution of burrows, vesicular or
vesicopustular lesions on the hands and feet,
extensive eczematization, multiple crusted
nodules on the trunk and limbs.
• Nodular scabies- in some cases, itching
nodules (5–20 mm in diameter, red, pink, tan
or brown in color) persist for several months.
They are found most commonly on the
scrotum (Fig. 9.11). Burrow may be seen on
the surface of early nodules.
• Scabies incognito means modified clinical
picture of classical scabies which mimic other
dermatoses due to inappropriate use of
• Complications of scabies: Secondary
infection of skin lesions, eczematization,
nephritogenic strains of streptococci may
produce secondary sepsis, and glomeru-
lonephritis particularly in tropics.
Fig. 9.8: Scabies—typical burrows of scabies of the
shaft of the penis
Fig. 9.9: Scabies in an infant—papulovesicular
lesions in finger web spaces
Fig. 9.10: Scabies in an infant – vesicular, pustular
and crusted lesions on the ankle and feet
• Diagnosis: If a mite is demonstrated, one
needs no diagnostic criteria. Typical lesions
on the penis and nipple, the presence of
burrows even without a mite and interdigital
lesions are almost diagnostic. Severe pruritus,
especially at night, of short duration or in
family members is also very suggestive.
• Burrow identification (Ink method): The
suspected burrow is smeared with blue or
black fountain pen ink and then wiped off
with an alcohol swab after some time. The
dye that enters the burrows is highlighted as
a dark line.
• Microscopic examination: The burrow is
scraped with 15 no. blade and examine the
material with 10% KOH or mineral oil under
light micrscope. Presence of mite, egg or fecal
concretions (scybala) confirms diagnosis of
• Under dermoscope, mite in burrow
resembles “jet with contrail”.
• Differential diagnosis:
A. For pruritic localized or generalized
rash: In infants: Papular urticaria,
infantile acropustulosis, In children:
Papular urticaria, insect bite reactions,
atopic dermatitis, animal scabies, In
adults: acute generalized lichen planus,
adverse drug reactions, contact
dermatitis, pediculosis pubis, pediculosis
corporis, different forms of prurigo, In
elderly: Dermatitis herpetiformis, senile
pruritis, delusional parasitosis.
B. For pruritic nodules: Urticaria
pigmentosa, papular urticaria (insect
bite), and pseudolymphoma.
• Therapy: Permethrin (5%) cream is
treatment of choice (single overnight
application below neck all over the body with
a second application after an interval of a
week). It is the treatment of choice for infants
(application includes head and neck also).
Sulfur and crotamiton are safe in pregnancy.
Other agents used are gamma benzene
hexachloride lotion (1%), benzyl benzoate
lotion (12.5% for infants and children, 25%
for adults), esdepallethrine 0.63%, malathion
0.5% lotion, ivermectin 0.8% lotion, and
monosulfiram (25%) diluted with two or
three parts of water to form an emulsion.
Ivermectin 200 microgram per kg body
weight single oral dose is also effective in
many cases of ordinary scabies, but
presumably because of lack of ovicidal
activity, higher cure rates are obtained with
two doses separated by an interval of a week.
It is a useful modality of treatment for
institutional outbreaks of scabies as it is
cheap, effective and easy to administer.
• Pruritus may persist for up to 1-2 weeks after
the end of effective treatment.
• Treat infested individuals as well as close
physical contacts simultaneously.
• Bedding and clothing should be washed in
hot cycle of washing machine.
• Intralesional triamcinolone 5-10 mg / ml in
each lesion is used for nodular scabies besides
routine scabies treatment.
Fig. 9.11: Nodular scabies—nodules seen
over the scrotum
Essentials in Dermatology76
• Very uncommon variant of scabies.
• Though the first report of crusted scabies was
in patients with leprosy, recent reports have
described an increasing incidence of this
form of scabies in patients with
immunosuppression due to immuno-
suppressive agents, malignancy or acquired
immunodeficiency syndrome (AIDS).
• In this form of scabies, the host’s response to
the mites is modified, allowing them to
multiply. As a result of this, the mite
population becomes enormous and may
• The large adherent crusts are most often seen
over the knees and elbows as well as the
hands (Fig. 9.12) and feet. There may even
be an erythroderma.
• Frequently, it can be confused with psoriasis,
chronic eczema (contact dermatitis),
Langerhans cell histiocytosis, or neuro-
dermatitis (Fig. 9.13).
• Ivermectin seems to be ideal drug for this
condition; otherwise prolonged therapy
with topical scabicidal agents is required.
Methotrexate is another option.
• Contracted from pet animals-cats, dogs, or
• No burrows seen, only itching and papulo-
vesicular lesions are seen over the site of
contact-abdomen, thighs and arms.
• Treatment of pet animal with scabicidal agent
and antipruritic agents for controlling itching
• Human skin lesions are self limiting; resolve
spontaneously if further contact with affected
animal is stopped.
Fig. 9.12: Crusted scabies – hyperkeratotic scaly
lesions over the palm and finger web space
Fig. 9.13: Crusted scabies—scaly cursted lesions
over the side of the buttock
Fig. 9.14: Pediculus humanus capitis
PEDICULOSIS (LICE INFESTATION)
• Pediculus humanus capitis (2 to 4 mm long)-
head louse (Fig. 9.14).
• Pediculus humanus corporis-body louse.
• Phthirus pubis-pubic louse (Fig. 9.15).
• Life cycle— these wingless six legged blood
sucking insects are obligate parasites specific
for humans, lays eggs. The ova (nits), which
are oval, 1 mm long and firmly attached to
the hair (Fig. 9.16) (or seems of clothing),
hatch in about 7-9 days and become mature
in another week.
• Body louse is the vector for the following
1. Rickettsia prowazekii (Endemic typhus),
2. Bartonella quintana (Trench fever),
3. Borrelia recurrentis (Relapsing fever).
• Extreme pruritus is the primary charac-
teristic of pediculosis.
• Incubation period—It takes 6 weeks
(approximately 30 days) for the pruritus to
develop in non-sensitized individual and
only 24 to 48 hours with repeat exposures.
• Most common in children especially girls
with long hairs.
• Mode of spread- human to human contact
or sharing combs, brushes and towels.
• Scalp-favorite site is area behind the ear
(Fig. 9.17) or occiput.
• Nits may be found most easily on the hairs.
Adult lice often impossible to find.
• In patients with scalp pruritus, secondary
pyoderma (with cervical lymphadenopathy)
and dermatitis, one should always search the
Fig. 9.15: Phthirus pubis
Fig. 9.16: Nits attached to the hair
Fig. 9.17: Pediculosis capitis – nits on the hair
Essentials in Dermatology78
hairs behind the ears carefully for nits. The
hairs may become matted from repeated
scratching (plica polonica) (Fig. 9.18).
• Differential diagnosis: Dandruff, here flakes
come off easily from hair on manipulation.
Hair casts look similar to nits but form an
encompassing cylinder whereas nits are
attached at an angle. Piedra is much less
common and consists of clumps of fungi.
• Permethrin 1% cream rinse (10 minute
application) is the treatment of choice. Repeat
application after one week is required to kill
hatched out nits. Pyrethrins, lindane,
malathion and benzyl benzoate are other
agents, which can be used topically.
Systemically, ivermectin, 200 µg/ kg body
weight, two doses at 7 days interval may be
used. Co-trimoxazole 1 tablet twice a day for
3 days, following that second course 7-10 day
• For nit removal: After treatment, hairs are
soaked with vinegar and water (50:50) and
then combed with fine toothed nit comb.
• Infestation associated with poor personal
hygiene, a disease of homeless.
• The body louse feeds on body and lays its
eggs on seems of clothing.
Fig. 9.18: Plica polonica—matting of the scalp hair
• Itching is the main symptom , which is due
to sensitivity to salivary antigens.
• Patients harbouring body lice for long time
develop hyperpigmentation of skin, develop
numerous excoriations (frequently most
noticeable on the side of trunk and back),
secondary infection and even lympha-
denopathy-vagabond’s skin, vagabond’s
itch, or vagabond disease (morbus errorum).
• For diagnosis: Closely examine the clothing
for lice and nits along the seams.
• Differential diagnosis: All pruritic
dermatoses especially scabies, contact
dermatitis, atopic dermatitis.
• Therapy: Clothes must be disinfected.
Topical antipruritics or corticosteroids are
given to the patient. A course of antibiotic
may be needed to take care of secondary
• Transmission in adults occurs mostly
during sexual intercourse.
• The pubic or crab louse is smaller than the
head or body louse, has resemblance to a crab
(for prominent claws in second and third
pairs of legs).
• Pruritus or crawling sensation is modest in
the pubic area.
Fig. 9.19: Phthriasis pubis – adult louse clung to
Fig. 9.20: Phthriasis palpebrarum – nits attached to
• Adult lice may be difficult to find and are
usually located at the base of hairs
resembling small freckles, scabs or moles
• Other than pubic hair, body and axillary hair
as well as eyelashes (phthiriasis palpe-
brarum) (Fig. 9.20) and beard should be
examined for nits.
• A classical clinical finding is the maculae
cerulea—flat, indistinct, blue grey or slate
colored macules in the infested area.
• All the treatments suggested for pediculosis
capitis are effective. Shaving the area is
another option. Infestation of the eyelids is
treated with twice daily applications of
petrolatum for 7 to 10 days. Alternative
treatments include anticholinesterase
(physostigmine) eye ointments, yellow oxide
of mercury, or fluorescein. The simplest
technique for the treatment of eyelid lice is
direct removal of the lice and nits with a fine
forceps. Cryotherapy may provide a fast cure.
Application of 1% gamma benzene
hexachloride cream and pyrethrin ointment
are other options.
• Papular urticaria occurs as episodic,
symmetrically distributed, pruritic,
urticarial papules that are caused by bites
of insects such as mosquitoes, fleas, and
• This condition is mainly seen in childhood.
• Treatment involves use of insect repellants,
topical antipruritic agents and antibacterial
with or without steroids.
LARVA MIGRANS ERUPTION
• Larva migrans eruption is usually caused by
filariform larvae of the dog and cat
hookworms, mainly Ancylostoma braziliensis
and rarely A. caninum, Uncinaria stenochepala,
Bunostomum phlebotomun, or the human
larvae of Necator americanus and Ancylostoma
• Adult hookworms live in the intestines of
dogs and cats and their ova are deposited in
the animals’ feces. Under favorable
conditions of humidity and temperature, the
ova hatch into infective larvae, which will
penetrate human skin. Sandy, warm, moist,
Fig. 9.21: Larva migrans eruption – serpentine
erythematous tract of larva migrans over the thigh of
Essentials in Dermatology80
shaded areas are particularly favorable and
humans acquire numerous infections.
• It is commonly known as creeping eruption
for its distinctive feature that the lesion creep
or migrate and is due to the presence of
moving parasite in the skin. An irregularly
linear, thin, raised burrow, 2-3 mm wide,
manifests this exceedingly itchy eruption
(Fig. 9.21). The larva moves a few mm to a
few cm per day. The eruption is self-limited
because humans are abnormal hosts.
• The feet and buttocks are the areas most
• Larva migrans can be accompanied by
Loeffler’s eosinophilia, particularly in severe
• The classic clinical picture of wandering,
serpentine and itchy lesion is easily
• Biopsy in larva migrans is of little value as
the larvae have advanced beyond the clinical
• Differential diagnosis is granuloma
annulare, migratory myiasis and larva
currens. Larva currens caused by filariform
larvae of Strongyloides stercoralis is
characterized by wheal and flare response
along the path of larvae, especially around
anus and buttocks. The linear or serpiginous
tracks of urticarial papules move at the rate
of several cm/ hour. Demonstration of larvae
of Strongyloides spp. in faeces confirms the
• The treatment of choice is the topical
application of 10% thiabendazole (not
available in India). Even the oral preparation
of thiabendazole or two tablets of 500 mg
thiabendazole crushed and formulated in
10 g petrolatum may be applied topically
twice daily. Systemic use of thiabendazole,
though effective, is contraindicated due to its
possible poorly tolerated side effects.
Ivermectin, in a single dose of 200 microgram
per kg body weight seems best. Albendazole
400 mg daily by mouth for 3 days is safe and
often effective. Flubendazole is currently at
an experimental stage, appears to offer good
• Myiasis is the presence of fly larvae
(maggots) in the tissue.
• Usually they need an entry site, such as a
chronic ulcer (trophic ulcer of leprosy) or
• Most maggots only eat necrotic debris,
although some attack healthy tissue.
• Clinically, myiasis is classified according to
the part of the body affected-cutaneous
myiasis (Fig. 9.22) (wound, furuncular),
nasopharyngeal myiasis, ophthalmomyiasis,
intestinal and urogenital myiasis.
• Therapy-remove the maggots either after
anesthetizing the area or suffocating them
with turpentine oil or petrolatum.
Leishmaniasis is a parasitic infection caused by
many species of the protozoa Leishmania,
manifested clinically as four syndromes.
Fig. 9.22: Myiasis—maggots in chromomycosis
lesion on the hand
• Old world type—Cutaneous leishmaniasis.
• New world type—Mucocutaneous leish-
• Diffuse Cutaneous Leishmaniasis
• Visceral leishmaniasis—Kala-azar.
• Transmitted by infected female sand fly—
Old world leishmaniasis by Phlebotomus
spp. and New world leishmaniasis by
Lutzomyia, Psychodopygus spp.
• Life cycle: The parasite exists in two forms:
a. Amastigote form in vertebrate host in
cells of reticuloendothelial system or
dermis. It has no flagellum.
b. Promastigote form in gut of female sand
fly and in culture media. It is motile with
an anterior flagellum.
• Oriental sore (Delhi boil, Baghdad boil) is
an old world cutaneous leishmaniasis caused
by Leishmania major, seen in Rajasthan and
adjoining areas in India.
• Unclothed parts of the body such as face,
neck, and forearms are usually involved. It
begins as papule that enlarges, ulcerates and
becomes crusted nodule with surrounding
induration (Fig. 9.23). Satellite lesions may
occur around the main lesion. Most of the
lesions heal by 6 months.
• Post kala-azar dermal leishmaniasis (PKDL)
occurs in 20% of the patients treated for
visceral leishmaniasis (Kala-azar) caused by
Leishmania donovani. It is mainly confined to
West Bengal, Orissa, Jharkhand and Bihar in
India. The lesions appear after a year of
therapy and manifest as hypopigmented
macules, papules and nodules over the trunk
and face. They closely resemble lepromatous
leprosy, secondary syphilis and yaws.
• Espundia is a type of mucocutaneous
leishmaniasis caused by Leishmania
• Chiclero ulcers are caused by Leishmania
• Diagnosis is by demonstration of amastigotes
inside macrophages from the lesion on a slit
skin smear and culture in NNN media.
• Treatment of cutaneous leishmaniasis.
A. Local therapy—Heating the sore
B. Local infiltration of 1-2 ml of sodium
stibogluconate or meglumine anti-
C. Systemic therapy: Antimonials—Sodium
stibogluconate or meglumine antimoniate
20 mg/kg/day for 14-21 days. Penta-
midine isethionate- 4 mg salt / kg –
weekly doses may be used.
D. Other drugs: Amphotericin B, keto-
conazole, itraconazole, dapsone,
Fig. 9.23: Cutaneous leishmaniasis—
noduloulcerative lesion over the forearm
Essentials in Dermatology82
10 Papulosquamous Disorders
Papulosquamous disorders are characterized by
raised, scaly papules and plaques, include
psoriasis, lichen planus, pityriasis rosea, lichen
nitidus, pityriasis rubra pilaris and other
conditions. These are discussed below.
• Psoriasis is a common chronic disfiguring,
inflammatory and proliferative epidermal
skin disorder mediated by T cells that affects
approximately 1 to 3% of the world
• Multifactorial inheritance most likely, a
family history of psoriasis is found in 30% of
• The histocompatibility antigen HLA Cw6 is
most strongly associated with psoriasis and
the coexistence of HLA B17 or B27 portends
more severe skin disease or associated
• The pathogenesis of psoriasis remains
unclear. The initial reaction is possibly an
intrinsic defect of keratinocytes with
increased cytokine production which leads
to expansion of CD45RO + T cells with
resultant production of type 1 cytokines.
Subsequently, it results in epidermal
proliferation, migration of neutrophils into
the epidermis, and proliferation of vessels in
the papillary dermis.
• The time necessary for psoriatic epidermal
cell to travel from the basal cell layer to the
surface and be cast off is 3 to 4 days, in
marked contrast to the normal 26 to 28 days.
• Precipitating factors— Stress and anxiety,
alcohol and smoking, drugs (chloroquine,
lithium, betablockers, ACE inhibitors,
NSAID’s, etc), sudden withdrawal of
systemic steroids, irritants, infections.
Classification of Psoriasis
1. Based on Morphological Types
• Chronic stable plaque psoriasis (psoriasis
vulgaris) (Figs 10.1 and 10.2)
• Guttate psoriasis
• Pustular psoriasis
• Erythrodermic psoriasis
• Rupioid, elephantine and ostraceous
2. Based on Site of Involvement
• Scalp psoriasis
• Flexural (inverse) psoriasis (Fig. 10.3)
• Nail psoriasis
• Palmoplantar psoriasis
• Genital psoriasis
• Psoriatic arthritis.
Papulosquamous Disorders 83
3. Atypical Forms of Psoriasis
• Linear and zonal lesions
• Seborrheic psoriasis
• Annular psoriasis
• Circinate psoriasis
• Nummular psoriasis
• Serpiginous psoriasis
• Geographic psoriasis
• Mucosal lesions— annular plaques, diffuse
areas of erythema, geographic tongue; very
• Ocular lesions— blepharitis, conjunctivitis,
keratitis, xerosis, symblepharon, trichiasis,
uveitis; extremely rare.
• Most lesions of psoriasis are asymptomatic.
• Its typical age of onset is in the third decade,
though it may develop at any time from birth
• Erythematous papules and plaques
characterize it. The lesions are of variable
size, sharply circumscribed, dry, and usually
covered with layers of silvery white,
micaceous scales (Figs 10.1 and 10.2).
• Grattage test involves scrapping a scaly
lesion to look for type of scales. Silvery white
Fig. 10.1: Psoriasis vulgaris–plaque lesions over
the extensor surface of limbs and trunk
Fig. 10.2: Psoriasis vulgaris–plaque lesions over
Fig. 10.3: Flexural psoriasis–psoriatic plaque
Essentials in Dermatology84
micaceous scales are found on doing grattage
test in psoriasis.
• Auspitz’s sign is typical of psoriasis. It
consists of three components:
1. Silvery white micaceous scales on
scrapping (due to parakeratosis)
2. Shiny membrane called Bulkley’s
membrane on continued scrapping (due
to suprapapillary thinning of epidermis)
3. Bleeding points on removal of membrane
(due to dilated capillaries in papillary
• Extensor surfaces of the extremities
(Fig. 10.1), the scalp (Fig. 10.4) and lumbo-
sacral region are commonly involved.
• Lesions of active psoriasis often appear in
areas of epidermal injury-Koebner pheno-
• An acute variant, guttate or eruptive
psoriasis is often seen in younger patients
and is characterized by an abrupt eruption
of small drop shaped lesions. It is associated
with acute group A beta hemolytic
streptococcal infection of pharynx in the
preceding 7 to 10 days.
• Nail involvement is common (50% of
psoriasis patients). The most frequent
alteration of nail plate surface is the
presence of pits (Fig. 10.5). Nail matrix
changes in psoriasis are pitting, longitudinal
ridging, grooves, leukonychia, erythema of
lunula (mottled erythema on lunula due to
matrix inflammation), thickening of nails,
crumbling of nail plate and trachynonychia.
Nail bed changes include subungual
hyperkeratosis, distal onycholysis, salmon
(oily) patches, splinter hemorrhages (thin red
or black longitudinal lines in distal portion
of nail due to psoriatic involvement of nail
bed capillaries, which are longitudinally
oriented). Paronychia results from
involvement of periungual skin of proximal
nail fold with retention of scales between
ventral nail fold and nail plate.
• Psoriatic arthritis is of various types— Distal
interphalangeal joint arthritis, asymmetrical
oligoarthritis, polyarthritis (rheumatoid
arthritis like), arthritis mutilans and
predominantly axial arthritis (psoriatic
spondylitis and/ or sacroiliitis). Psoriatic
Fig. 10.4: Psoriasis vulgaris–lesions extending
beyond hair line
Fig. 10.5: Psoriasis vulgaris–nail pitting
Papulosquamous Disorders 85
arthritis characteristically involves the
terminal interphalangeal joints (Fig. 10.6), but
frequently the large joints are also affected,
resembling rheumatoid arthritis. However,
the rheumatoid factor is absent.
• In severe cases, the disease may affect the
entire skin and presents as psoriatic
• Psoriasis rarely presents as generalized
pustular psoriasis (von-Zumbusch type-
acute exanthematic type (Fig. 10.7) or
generalized pustular psoriasis of pregnancy-
Impetigo herpetiformis). Localized pustular
psoriasis occurs as acrodermatitis continua
of Hallopeau (localized to the distal portions
of the hands and feet) (Fig. 10.8) or pustulosis
palmaris et plantaris (chronic, relapsing
disorder occurring on the palms, soles, or
• Psoriasis may be confused with seborrheic
dermatitis, secondary syphilis, dermatophyte
infections, cutaneous lupus erythematosus,
eczema, lichen planus, pityriasis rosea,
Bowen’s disease or lichen simplex chronicus.
• Diagnosis is mostly clinical supplemented at
times of doubt by histopathology of skin
Fig. 10.6: Psoriatic arthritis—characteristically
involving distal interphalangeal joint leading to swan
Fig. 10.7: Generalized pustular psoriasis-
generalized pustular eruption in a child
Fig. 10.8: Acrodermatitis continua—nail dystrophy
and finger tip involved by pustular psoriasis
Essentials in Dermatology86
• Histopathology: The fully developed lesion
of psoriasis shows:
1. Hyperkeratosis and parakeratosis.
2. Within parakeratotic areas of the horny
layer, accumulations of neutrophils
forms, which are called as Munro micro-
3. Hypo or absent granular layer.
4. Regular acanthosis.
5. Spongiform pustule of Kogoj—
neutrophils accumulation in Malpighian
6. There is regular elongation of the rete
ridges with thickening in their lower
portion, looking like elephant feet.
7. There is thinning of the supra papillary
portion of the epidermis.
8. The dermal papillae contain enlarged and
tortuous capillaries that are very close to
the skin surface and impart a
characteristic erythematous hue to the
9. Sparse lymphocytic infiltrate in the upper
Differential Diagnosis of Psoriasis
• Seborrhoeic dermatitis— In the scalp,
lesions are lighter in color, less well defined,
covered with dull or branny or greasy scales,
with absence of corona.
• Pityriasis rosea— Papular or annular
eruption usually confined to upper arms,
trunk and thighs. Herald patch is followed
by disseminated eruption, which has
christmas tree pattern. Typically individual
lesion shows collarette of scaling. Duration
of disease is few weeks (6-8 weeks), and it
has self limiting course.
• Pityriasis rubra pilaris resembles closely the
psoriasis especially in the erythrodermic
phase. The follicular accentuation, focal areas
of sparing (islands of normal skin),
sometimes more salmon coloration of
pityriasis rubra pilaris and the acquired
palmoplantar keratoderma with yellow
orange tinge help to differentiate the
condition clinically; biopsy sections of
pityriasis rubra pilaris may show follicular
plugging, parakeratotic shoulder and
perifollicular lymphohistiocytic infiltrate.
• Dermatophyte infection (tinea corporis)—
Itchy annular erythematous plaque/s with
peripheral scaling, KOH examination
• Discoid lupus erythematosus— Discrete
erythmatous plaques on face and scalp
(usually on sun-exposed areas), associated
with atrophy, scaling and alopecia. Scales of
discoid lesions are grayish and adherent.
There is follicular plugging and carpet-tack
• Subacute lupus erythematous— Presents
with annular erythematous or psoriasiform
lesions associated with systemic component,
may have other components of systemic
• Eczema at times develops a psoriasiform
appearance especially on the legs.
Hyperkeratotic eczema of palms is a common
cause of misdiagnosis. Color, scratch evoked
scaling and well defined margins are
suggestive of psoriasis and nail changes may
• Lichen planus— It involves flexor surface of
forearm and wrists, and shins and ankles.
Pruritic purple flat topped papules and
plaques with scanty and tightly adherent
scales. Scalp is much less frequently involved.
Nails are longitudinally ridged, thickened or
thinned out, with pterygium a characteristic
finding. No nail pitting. Linear lichen planus
may mimick linear psoriasis but the
individual lesion characterstics helps in
• Secondary syphilis— Asymptomatic
eruption, brownish sparse scales, generalized
lymphadenopathy, mucous patches, condy-
loma lata, positive serological test for syphilis.
Papulosquamous Disorders 87
• Drug eruptions— Always take a drug
history; many drug reactions are
psoriasiform, and in some instances lead to
true psoriasis in susceptible host.
• Pityriasis lichenoides chronica— It can
closely resemble guttate psoriasis but the
lesions are less evenly scattered, have
brownish red or orange brown color and are
capped by an opaque soft mica like scale.
• It is important to emphasize that psoriasis is
a treatable condition. The treatment pyramid
for psoriasis is shown in Fig. 10.9.
• Despite virtual explosion in therapeutic
options, the management of psoriasis
remains a challenge to clinicians.
• Emollients— Such as coconut oil, vaseline,
or liquid paraffin.
• Coal tar (2, 5, 10% ointment)— It may be used
effectively as monotherapy or in combination
with other treatment modalities.
Goeckerman therapy consists of black crude
coal tar application all over the patient’s
body. This tar is left on for 24 hours per day.
UVB phototherapy is administered before the
tar is applied or after it is washed off. The
Goeckerman regimen remains an intensive
daily therapy that is usually conducted for a
period of several weeks.
• Anthralin (0.1 to 10% cream or ointment)—
It is moderately effective and quite safe in
plaque psoriasis. The major side effect is
staining of skin and clothing and occasional
irritation. Ingram regimen consists of a
combination of anthralin and UVB
phototherapy. Short contact treatment of 30
minutes or less is likely to reduce irritation.
• Topical steroids/ intralesional steroids-
Topical corticosteroids are used for treatment
over face and neck, flexures and genitalia,
where tar or anthralin would cause irritation
and cannot be used. Systemic steroids
generally not recommended due to the well-
known risk of rebound and pustular
• Vitamin D analogues are both naturally
occurring – calcitriol (1α, 25-dihydro-
xyvitamin D3) and synthetic analogues-
calcipotriol, tacalcitol, maxacalcitol. Vitamin
D molecule is dispensed as ointment, cream
or solution and has risk of producing
hypercalcemia in less than 1% of cases.
• Tazarotene (0.1 to 0.05% gel)— It is a
modified vitamin A molecule formulated as
a topical agent. It is recommended for use in
patients with total body surface involvement
of 20% or less.
• Topical methotrexate gel-used for
palmoplantar psoriasis with limited efficacy.
• Tacrolimus (0.03, 0.1%) effective for facial
plaques and inverse psoriasis.
Medications Used in Phototherapy
• Concurrent use of topical or oral medications,
psoralen (5 methoxy psoralen, 8 methoxy
psoralen, trimethyl psoralen) along with
UVA or UVB phototherapy is done.
• Psoralen along with UVA from sunlight
• Narrow band UVB.
• Methotrexate and PUVA combination
• Retinoids and PUVA combination (Re-
• Excimer LASER (308 nm).
Systemic Medications for Psoriasis
• Methotrexate (0.4 to 0.6 mg per kg body
weight)— Used for severe cases of psoriasis,
taken orally just once a week. It is an effective
and well tolerated drug in appropriately
selected patients who are receiving folate
supplementation, and who are adequately
monitored for potential toxicities.
• Cyclosporine (3-5 mg per kg body weight).
Cyclosporine has dose-related nephrotoxicity
and hypertension that impede its use as a
Essentials in Dermatology88
long-term agent for most patients.
Nevertheless, cyclosporine is an effective
drug for rapid clearing in most patients.
Cyclosporine, when used in the appropriate
patient at the appropriate dose (usually 2.5
to 5.5 mg/kg daily), is an excellent “bridging
agent” that can be used safely for periods of
• Etretinate and Acitretin (0.5-1 mg per kg
body weight)— They are the treatment of
choice for generalized pustular psoriasis.
Acitretin is less effective when used as
monotherapy for plaque psoriasis.
• Hydroxyurea (maximum up to 500 mg three
times a day).
• Sulfasalazine (3-4 gm/day).
• Mycophenolate mofetil ( 1-2 gm/day, can
increase maximum up to 4 gm/day).
• Oral tacrolimus ( 0.05- 0.15 mg/kg body
weight per day).
• Fumaric acid esters 30 mg per day up to 240
mg three times a day.
• Many of these medications are used in
combination and rotated periodically.
• HIV associated psoriasis may respond to
zidovudine based HAART regimen.
Biologics are agents that selectively block the
immunologic steps in the pathogenesis of
psoriasis. Alefacept, efalizumab, etanercept, and
infliximab are currently approved for the
treatment of adults with moderate to severe
plaque psoriasis, and phase 3 trials for
adalimumab are ongoing (Table 10.1).
• All biologics approved to date for the
treatment of psoriasis are recommended for
patients who are candidates for systemic or
Fig. 10.9: Treatment pyramid of psoriasis
Table 10.1: Biologic agents and their
mechanism of action
Strategy Biologic agents
Reduction of the number Alefacept, denileukin
of pathogenic T cells diftitox
Inhibition of T-cell Efalizumab, daclizumab,
activation and migration siplizumab, CTLA4Ig,
Modulation of the immune Ilodecakin, oprelvekin
Blockage of the activity of Etanercept, infliximab,
inflammatory cytokines adalimumab, ABX-IL8
Papulosquamous Disorders 89
• Efalizumab is favorable in patients with high
risk of latent tuberculosis or evidence of
• Infliximab is advantageous where rapid
disease control is required (e.g. unstable
• Etanercept is the biologic of choice in stable
psoriasis where a TNF-α-blocking strategy is
• Some biologics are also approved for
treatment of psoriatic arthritis; thus, patients
with psoriatic arthritis may benefit from a
biologic for both the articular and dermato-
Course and Prognosis
• The course of psoriasis is prolonged but
• Reiter’s disease predominantly affects young
men and consists of the triad of urethritis,
arthritis, and conjunctivitis. As few patients
present with classic triad, the American
College of Rheumatology recognizes criteria
for limited manifestations of this syndrome
including peripheral arthritis of more than
one month duration in association with
urethritis, cervicitis or bilateral conjunctivitis.
Fig. 10.10: Reiter’s disease–typical limpet like scales
Fig. 10.11: Reiter’s disease–typical lesions over legs
Fig. 10.12: Reiter’s disease-circinate balanitis
• Cutaneous lesions occur in about half of
affected patients. The cutaneous eruption has
limpet like scales (Figs 10.10 and 10.11).
Lesions have a predilection for the glans
penis (balanitis circinata) (Fig. 10.12), the
palms and soles (keratoderma blennor-
rhagica) and the subungual areas.
• HLA B 27 is present in about 80% of cases
• Most cases of Reiter’s disease are probably
caused by infection with micro-organisms
that infect urogenital or gastrointestinal
systems such as Chlamydia trachomatis,
Essentials in Dermatology90
Ureaplasma urealyticum, Shigella, Salmonella,
• Differential diagnosis includes rheumatoid
arthritis, ankylosing spondylitis, gout,
psoriatic arthritis, gonococcal arthritis, acute
rheumatic fever, etc.
• Mucocutaneous lesions are generally self
limited and clear with topical steroids.
Refractory lesions are managed like psoriasis.
Joint disease may require NSAIDS,
methotrexate or biologics (infliximab).
• Lichen planus (Greek leichen, “tree moss”;
Latin planus, “flat”) is a subacute or a chronic
dermatosis that may involve skin, mucous
membranes, hair follicles and nails.
• The cause of lichen planus is unknown, but
several etiologies have been proposed. It is
likely that both endogenous-genetic and
exogenous-environmental components such
as drugs or infection may interact to elicit
• The prevalence of chronic liver diseases,
including primary biliary cirrhosis, alcoholic
cirrhosis, hepatitis B, and especially hepatitis
C, is increased.
• HLA-B8 is more common in patients with
oral lichen planus as the sole manifestation,
and HLA-Bw 35 is more strongly associated
with cutaneous lichen planus.
• At least two-thirds of cases occur between
the ages of 30 and 60 years.
• Cutaneous eruption is characterized by
small, flat topped, shiny, polygonal,
violaceous papules that may coalesce into
plaques (Fig. 10.13)
• The papules often show a network of white
lines known as Wickham’s striae.
• Koebner phenomenon commonly seen (Fig.
• Itching is usually pronounced.
• The four P’s – purple, polygonal, pruritic,
papule- is the abbreviation used to recall the
constellation of symptoms and skin findings
that characterize lichen planus.
• The disease has a predilection for the flexor
surfaces of the forearms (Fig. 10.15), legs
(Fig. 10.16), trunk (Fig. 10.17), and the
genitalia including the glans penis (Figs
10.18 to 10.20).
Fig. 10.13: Lichen planus–violaceous, flat-topped
Fig. 10.14: Lichen planus–wrist involved, Koebner
phenomenon also seen
Papulosquamous Disorders 91
• The oral lesions of lichen planus are
frequently found, either as sole manifestation
of the disease or associated with cutaneous
involvement. Most often consist of a lacy,
reticular network of coalescent papules over
the buccal (Fig. 10.21) or glossal mucosa.
Besides this, it forms plaque like, atrophic,
papular, erosive and bullous lesions.
• The nails are involved in about 10% of cases
and show roughening, longitudinal ridging,
thinning and dystrophy. Pterygium
Fig. 10.15: Lichen planus–flexor aspect of arm
Fig. 10.16: Lichen planus–hypertrophic violaceous
papules and plaques over legs
Fig. 10.17: Lichen planus–trunk involved by typical
violaceous papular lesions
Fig. 10.18: Lichen planus–an annular lesion over
the glans penis
Fig. 10.19: Lichen planus–male genitalia involved
by lichen planus
Essentials in Dermatology92
formation is a frequent finding (Fig. 10.22).
• Common variants of lichen planus (LP) are
classified on the basis of:
A. Configuration (annular, linear,
zosteriform/along Blaschko’s lines (Fig.
B. Morphology of lesions (hypertrophic,
atrophic, vesicobullous, erosive,
ulcerative, follicular [planopilaris], actinic
(Fig. 10.24), LP pigmentosus, perforating,
C. Site of involvement (palms and soles,
mucous membranes, nails, scalp),
Fig. 10.20: Lichen planus–female genitalia involved
by lichen planus
Fig. 10.21: Lichen planus–lacy white network over
the buccal mucosa
Fig. 10.22: Lichen planus–pterygium unguium
formation in some finger nails
Fig. 10.23: Lichen planus–transeversely aligned
lichen planus along Blaschko’s lines
D. Special forms (drug induced, overlap
syndrome of lichen planus/lupus
erythematosus, LP pemphigoides).
• The appearance of the typical papule of
lichen planus is usually sufficient to make the
• Histopathology: Microscopic features, similar
to the gross morphology, are diagnostic. The
two major pathologic findings in lichen
planus are basal epidermal keratinocyte
damage and lichenoid-interface lympho-
Papulosquamous Disorders 93
cytic reaction. The histologic features are
2. Wedge shaped hypergranuloses which is
responsible for the Wickham’s striae seen
3. Irregular acanthosis
4. Damage to basal cell layer
5. The rete ridges are pointed at their lower
end and the papillae between rete ridges
are often dome shaped thus resembling
the old styled bridges on rivers having
tapering down pillars and domes in
between. This pattern is also called as
6. A band-like dermal lymphocytic
infiltrate closely hugs the epidermis.
7. Max-Joseph spaces are seen in some cases
as a sub-epidermal clear zone.
Melanin incontinence and vascular
inflammatory reaction probably give purple
colour to LP lesions.
• Classic lesions: Lichenoid drug eruption
(large scaly lesions in sun-exposed areas,
devoid of Wickham striae, residual
pigmentation common), lichen nitidus
Fig. 10.24: Lichen planus actinicus–typical
hypopigmented halo around pigmented violaceous
lesions over the face
(asymptomatic pinhead sized shiny papular
lesions, rarely involves mucous membranes),
secondary syphilis, pityriasis lichenoides et
varioliformis acuta, early pityriasis rubra
• Hyperkeratotic lesions: Lichen simplex
chronicus, prurigo nodularis, lichen amylo-
• Linear lesions: Lichen striatus, linear
epidermal naevus, linear psoriasis.
• Annular lesions: Granuloma annulare,
secondary syphilis, psoriasis
• Lichen planopilaris: For early lesions-
keratosis pilaris, other follicular keratoses,
Darier’s disease, early pityriasis rubra pilaris.
For advanced lesions-discoid lupus erythe-
matosus, and other forms of scarring
• Wide-spread erosive oral lesions must be
differentiated from those of candidiasis
(curdy white deposits which on removal
leaves an erythematous base. KOH scrapping
shows budding yeasts, pseudohyphae),
aphthous ulcers (well circumscribed shallow
ulcers with a necrotic gray centre and an
erythematous halo. It usually heals in around
six weeks) pemphigus (ill defined irregular
buccal or palatal non healing painful
erosions. Other mucosal sites may also be
involved. Nikolsky’s sign positive), cicatricial
pemphigoid (vesicles, persistent extensive
erosions, desquamative gingivitis with
eroded bleeding gums, adhesions between
buccal mucosa and alveolar process and
around uvula and tonsillar fossae,
involvement of other mucosal sites including
conjunctiva, genital mucosa, larynx and
esophagus, and decreased mouth opening
due to fibrosis), carcinoma (usually
malignant ulcers are painless unless
secondarily infected. On palpation
induration of base may be present), and
erythema multiforme (usually involves lips,
Essentials in Dermatology94
palate and gingival. On lips, target lesions
may be identified. Vesicles, erosions and
crusting are present over oral mucosa.
Associated skin lesions- target lesions may
be seen over acral extensor sun-exposed
• Topical therapy: Topical glucocorticoids are
typically used for mucosal and limited
• Intralesional therapy: Intralesional triam-
cinolone acetonide (5 to 10 mg/mL) is
effective in treating oral and cutaneous lichen
• Systemic therapy:
1. Systemic glucocorticoids are often useful and
effective in doses greater than 20 mg/day
(e.g. 30 to 60 mg prednisolone) for 4 to 6
weeks with subsequent taper over 4 to 6
2. PUVA photochemotherapy is usually
successful in generalized cutaneous lichen
3. The systemic retinoids demonstrate anti-
inflammatory activity and have been used in
the treatment of lichen planus.
4. Cyclosporine (500 mg) rinses in oral lichen
and systemic cyclosporine in recalcitrant
lichen planus has been used successfully.
5. Other agents used in lichen planus are
dapsone, griseofulvin, cyclophosphamide,
methotrexate, phenytoin and extracorporeal
In mucosal lichen planus, topical corticos-
teroids, tetracycline, betamethasone mouth-
washes 0.5 mg 3-4 times daily, topical tretinoin
gel, cyclosporine mouth rinses, tacrolimus, and
pimecrolimus have been used. Maintenance of
good oral hygiene and replacement of amalgam
or gold dental restorations with composite
material is frequently of considerable benefit.
Erosive oral lichen planus may respond to oral
Lichen planus is a benign disease with
spontaneous remissions and exacerbations.
Apart from hypertrophic lichen planus, most of
LP lesions tend to involute after several months
to a year.
• Lichen nitidus is a chronic dermatitis usually
asymptomatic which begins commonly in
childhood or early adulthood
• It is characterized by minute, round, flat or
dome shaped, shiny, flesh colored papules
2 to 3 mm in diameter that may occur in
• Predominantly, the arms, trunk (Fig. 10.25)
or penis (Fig. 10.26)are involved
• Koebner phenomenon may be observed (Fig.
• The histology of a typical papule is
characteristic. A circumscribed epithelioid
cell granuloma is situated immediately below
the epidermis. The rete ridges at the margin
of the infiltrate are elongated and tend to
encircle it “claw clutching a ball
• Differential diagnosis:
1. Keratoses pilaris (horny follicular papules
on extensor surfaces),
Fig. 10.25: Lichen nitidus–flat, shiny, flesh colored
papules on the trunk
Papulosquamous Disorders 95
2. Lichen scrofulosorum (grouped follicular
papules in small patches on trunk),
3. Lichen planus,
5. Disseminated granuloma annulare,
6. Eruptive xanthomas,
Fig. 10.26: Lichen nitidus–flat, shiny, flesh colored
papules on the glans penis
Fig. 10.27: Lichen nitidus- over the arm showing
7. Plane warts (more variable in size, have
verrucous surface and present with fewer
lesions with few anatomic sites involved)
• As the disease is often asymptomatic and
eventually self-limiting, no treatment is
required in most cases
• Topical steroids may be recommended if
treatment is demanded.
• Pityriasis rosea is a self limited dermatitis
lasting from 4 to 7 weeks.
• The etiology is unknown, though a viral
origin has been suggested.
• Predominantly occurs in adolescents and
• May be asymptomatic or pruritic (50% of
• It frequently starts with herald patch (mother
patch, plaque primitive, primary medallion,
primary plaque) (most commonly on the
trunk) followed by a disseminated eruption
(the trunk and proximal extremities) within
several days to 2 weeks (Fig. 10.28).
Sometimes, herald patch may be missing, or
present as double or multiple lesions often
Fig. 10.28 Pityriasis rosea–herald patch with a few
daughter lesions showing “collarette of scaling”
Essentials in Dermatology96
• Round to oval salmon colored patches
following the lines of cleavage (Christmas
tree like pattern) and showing peripheral
attached thin cigarette paper like scales
(“collarette of scaling”) (Fig. 10.28). When
individual lesion is stretched along the long
axis, the scales tend to fold across the lines of
stretch, so called “hanging curtain sign”.
• Variants of pityriasis rosea are vesicular,
inverse (Fig. 10.29), cervicocephalic, pityriasis
rosea gigantea (pityriasis circinata et
marginata of Vidal), pityriasis rosea urticata,
purpuric pityriasis rosea, pityriasis rosea
perstans, pustular pityriasis rosea, and
eczematous pityriasis rosea.
• Usually easily diagnosed by its morphology
• Pityriasis rosea must be differentiated from
tinea corporis, tinea versicolor (well defined
hypopigmented coalescing macules with branny
scales), drug eruptions (acute onset without
herald patch, pruritic protracted rash and a
tendency for lesions to become lichenoid),
psoriasis (papules and plaques with silvery
Fig. 10.29: Inverse pityriasis rosea – lesions over
white micaceous scales), parapsoriasis, pityriasis
lichenoides chronica, lichen planus, and, most
importantly, secondary syphilis (maculopapular
lesions, no herald patch, genital and oral mucosal
• Most patients require no treatment.
• Topical corticosteroids or short course of oral
corticosteroid may be required in severe
• Oral erythromycin may be helpful.
• Itching alleviated with antipruritic lotions or
PITYRIASIS RUBRA PILARIS (PRP)
• Pityriasis rubra pilaris is an erythematous
squamous disorder characterized by
seborrheic dermatitis like rash which
progresses cephalo-caudally, follicular
plugging and perifollicular erythema that
coalesces to form orange red scaly plaques
(Fig. 10.30) that frequently contain islands of
normal appearing skin (Fig. 10.31), proximal
phalanges showing typical follicular
plugging and palms and soles keratotic
sandal (palmoplantar keratoderma)
Fig. 10.30: Pityriasis rubra pilaris – follicular papular
lesions coalescing to form plaques over the trunk
Papulosquamous Disorders 97
• It may progresses to erythroderma.
• Both familial and acquired forms of the
disorder have been described.
Types of PRP
• Type I—adult onset classical, most common
• Type II—adult onset atypical.
• Type III—juvenile onset, classical.
Fig. 10.31: Pityriasis rubra piliaris–islands of
normal skin in a patient having erythroderma
Fig. 10.32: Pityriasis rubra pilaris–palmoplantar
keratoderma (keratotic sandal)
• Type IV—juvenile onset, circumscribed.
• Type V—juvenile onset, atypical.
• Type VI—HIV associated.
• Histopathology reveals hyperkeratosis and
follicular plugging with shoulder of
parakeratosis. Parakeratosis may alternate
both vertically and horizontally producing a
• Differential diagnosis: Closely resembles
psoriasis but prominent facial involvement
or follicular lesions speak against it. Early
scalp involvement is often mistaken for
atopic dermatitis or seborrhoeic dermatitis.
Early diffuse lesions are confused with lichen
planus and pityriasis lichenoides et
varioliformis acuta. Circumscribed pityriasis
rubra pilaris mimics phrynoderma or
• Treatment: Topical therapy with keratolytic
agents, vitamin D analogues and systemic
therapy with vitamin A, acitretin, isotretinoin
(systemic retinoid), methotrexate and
retinoid plus psoralen and ultraviolet A (Re-
PUVA) has been tried with variable efficacy.
Antiretroviral therapy is of value in pityriasis
rubra pilaris like eruption of HIV infection.
• The inherited form of the disorder is
persistent throughout life while the acquired
disease usually shows remissions and
• Erythroderma is a condition which is
characterized by erythema, infiltration and
scaling involving more than 90% of the body
surface area or near universal involvement
of the body (Fig. 10.33).
• Erythroderma can be caused by various
dermatological disorders: eczema, psoriasis,
drugs, lymphoma, leukaemia, pemphigus
foliaceus, ichthyosiform erythroderma,
pityriasis rubra pilaris, lichen planus,
Essentials in Dermatology98
• In erythroderma where the etiology is
unknown, called as idiopathic erythroderma
(10% of cases).
• Chronic erythroderma of unknown origin
with prolonged course in the elderly is called
as ‘red man syndrome’.
• Sézary syndrome manifest with erythro-
derma, generalized lymphadenopathy and
atypical cells in peripheral smear (more than
• It can be a manifestation of internal
• Erythroderma leads to hemodynamic and
metabolic disturbances such as high out put
cardiac failure, hypothermia, dehydration
• Temperature regulation is affected and
patient behaves like a poikilothermic animal.
• Death may occur due to cardiac failure,
pneumonia and septicemia.
It includes maintenance of the homeostasis and
treatment of the primary disease.
Fig. 10.33: Erythroderma – near universal
involvement by erythema, scaling and infiltration
dermatomyositis, dermatophytosis and
• The drugs causing erythroderma are
phenytoin, carbamazepine, cimetidine,
lithium, gold, chloroquine, isoniazid,
mercury, thiazide, quinidine and pyrazolone
The word eczema is derived from the Greek
word “ekzein” meaning “to boil out” or “to
effervesce”. Eczema is an inflammatory skin
reaction characterized histologically by
spongiosis with varying degrees of acanthosis,
and a superficial perivascular lympho-histiocytic
infiltrate. The clinical features of eczema may
include itching, redness, scaling and clustered
papulo-vesicles. The condition may be induced
by a wide range of external and internal factors
acting singly or in combination.
The terms ‘dermatitis’ and ‘eczema’ are
nowadays generally regarded as synonymous,
although some authors still use the term
‘dermatitis’ to include all types of cutaneous
inflammation, so that all eczema is dermatitis,
but not all dermatitis is eczema.
CLASSIFICATION OF ECZEMA
• Irritant dermatitis
• Allergic contact dermatitis
• Photoallergic contact dermatitis
• Eczematous polymorphic light eruption
• Infective eczema
• Post-traumatic eczema.
• Atopic dermatitis
• Seborrheic dermatitis
• Asteatotic eczema
• Discoid eczema
• Pityriasis alba
• Stasis dermatitis
• Hand eczema
• Lichen simplex chronicus
• Prurigo nodularis
• Lichen striatus
• Juvenile plantar dermatosis
• Metabolic eczema or eczemas associated with
• Eczematous drug eruptions.
It must be remembered that, endogenous and
exogenous factors may co-exist. For example,
hand eczema, which is an endogenous eczema,
is often aggravated by exogenous factors. Some
of the important endogenous (Atopic dermatitis,
seborrheic dermatitis, nummular eczema,
pompholyx, pityriasis alba, stasis dermatitis,
asteatotic eczema, lichen simplex chronicus,
prurigo nodularis, lichen striatus) and exogenous
eczema (Contact dermatitis, infective eczema/
dermatitis, polymorphous light eruption) are
discussed as follows.
Essentials in Dermatology100
• Atopic dermatitis (AD) or eczema is a
common chronic or relapsing dermatitis
characterized by severe pruritus, occurring
primarily in infants and children.
• The age of onset is between 2 and 6 months
in the majority of cases, but it may start at
any age, even before the age of 2 months in
• The disease arises as a result of a complex
interplay between various genetic,
immunological and environmental factors.
• The environmental factors include (a)
physical factors like sweating, climate, warm
surroundings, detergents and soap, synthetic
or woollen fabrics, cigarette smoke,
(b) psychological factors, (c) food items
(including tomato, orange and citrus fruits
juices, meat, fish) (d) allergens such as house
dust mite, animal hair, pollen, plants and
others such as Staphylococcus aureus and
release of exotoxins (superantigens) and
saliva in small children.
• Majority of cases are associated with a
sensitization to environmental allergens
and increased serum IgE (extrinsic AD), but
about 10-30% of all cases lack any link to
the classical atopic diathesis and are
labelled as intrinsic AD.
• There is no laboratory gold standard for the
diagnosis of AD. A detailed history and a
characteristic clinical picture would
establish the diagnosis. Hanifin and Rajka
have laid down certain major and minor
criteria for making a diagnosis of AD.
Must have Three or More Major Findings
• Typical morphology and distribution
(Flexural lichenification or linearity in adults;
Facial and extensor involvement in infants
• Chronic or chronically relapsing dermatitis
• Personal or family history of atopic dermatitis
(e.g. asthma, allergic rhinitis, atopic
Plus Three or More Minor Findings
• Palmar hyperlinearity
• Keratosis pilaris
• Immediate (type 1) skin test reactivity
• Elevated serum IgE level
• Early age of onset
• Tendency towards extraneous infections
(especially with Staphylococcus aureus and
herpes simplex) or impaired cell mediated
• Propensity towards nonspecific dermatitis of
the hand or foot.
• Nipple eczema
• Recurrent conjunctivitis
• Dennie -Morgan infraorbital fold
• Anterior subcapsular cataracts
• Orbital darkening
• Pityriasis alba
• Facial pallor or facial erythema
• Anterior neck folds
• Itch when sweating
• Intolerance to wool and lipid solvents
• Food intolerance
• White dermographism or delayed blanch.
Course of atopic dermatitis may be divided in
1. Infantile phase
2. Childhood phase
3. Adult phase
The distribution of lesions varies with age: Face
(Fig. 11.1)and scalp involvement is common in
infants as well as the extensor surfaces of the
extremities and the trunk. In the childhood phase
of AD 18-24 months onwards, eczema is
Fig. 11.1: Atopic dermatitis—face
Figs 11.2 and 11.3: Atopic dermatitis–discoid eczematous lesions also
appearing on flexor aspect of limbs in a child
Fig. 11.2 Fig. 11.3
Essentials in Dermatology102
observed on the flexural surfaces, including the
neck, antecubital or popliteal fossae, wrists and
ankles (Figs 11.2 and 11.3). There is an adult
phase, which occurs in adolescents and adults,
where lichenification of the flexures and the
hands commonly occurs.
Some important signs: Thinning of lateral
eyebrows, Hertoghe’s sign is sometimes present.
Hyperkeratosis and hyperpigmentation
producing a “dirty neck” appearance is also
frequent in atopic individuals. Atopic
individuals often exhibit perioral, perinasal and
periorbital pallor “headlight sign”.
Differential diagnosis: The diagnosis of atopic
dermatitis (AD) is rarely aided by investigations.
In the individual patient, one must consider a
number of other conditions. Scabies should
always be excluded, and can cause confusion
when superimposed on pre-existing AD. In the
first few months of life, the differentiation of
infantile seborrhoeic dermatitis from atopic
dermatitis can be difficult, although with time
the distinction becomes apparent. The most
useful distinguishing feature between atopic
dermatitis and seborrheic dermatitis is the
increased number of lesions on the forearms and
shins in the former and axillae in the latter. The
development of the lesions solely in the diaper
area favors a diagnosis of infantile seborrheic
dermatitis. Absent to mild pruritus is considered
a significant feature of infantile seborrheic
dermatitis. Immunodeficiency states should
also be considered in infants in whom the disease
is unusually severe, when there are recurrent
systemic or ear infections and if there is failure
to thrive, malabsorption or petechiae. Then
appropriate investigations should be performed,
for example, immunoglobulin levels and
subclasses, IgE levels, white cell count, platelets,
complement levels, and function, and T, B, and
phagocyte numbers and functions. If clinically
appropriate, one may also consider testing for
HTLV-I and human immunodeficiency virus
Treatment: No disease is more complicated to
treat than atopic dermatitis. It is absolutely
essential to counsel and educate the patient and
their parents. Avoidance of exacerbating factors
like wool clothes, house dust mites, detergents,
dietary or aero-allergens, stress, etc. is advised
wherever implicated. The treatment is aimed at
suppressing the symptoms and controlling or
preventing complications. Besides emollients for
routine skin care, topical corticosteroids (TC) are
the mainstay of treatment for AD to control
acute exacerbations and can be used safely if
certain precautions are taken. Topical calcineurin
inhibitors (TCIs: Tacrolimus 0.03% and 0.1% and
Pimecrolimus 1%) are recommended in patients
of AD who are unresponsive to or intolerant to
other conventional therapies, should be applied
over the affected areas twice daily. Tacrolimus
0.03% and 0.1% formulations are recommended
for the use in adults, whereas only 0.03%
formulation is recommended for use in children
aged 2-15 years, often first line for face,
intertriginous areas and genitalia, useful in early
flare, continue treatment till disease clears
(approximately 1 month), and is useful for
maintenance therapy. Systemic corticosteroids
have a limited role in tiding over occasional flares
of severe AD. Sedative antihistamines such as
hydroxyzine and promethazine are preferred to
non-sedative ones to control pruritus. Avoidance
of provoking factors is paramount to achieve
• Other treatment modalities include
phototherapy and photochemotherapy,
cyclosporin, evening primrose oil, azathio-
prine, Chinese herbal medicines, interferons,
thymopentin, human interferon gamma and
• Algorithmic approach to management
depending upon severity of AD.
1. Mild AD Bland emollients and parents/patient counseling
Mild to moderate TCs, followed by TCI or
TCI as first line of therapy
2. Moderate AD Bland emollients and parents/patient counseling
Initial control with TCs and at the earliest shift to TCI’s
Narrow band UVB
Systemic corticosteroids for short period
3. Severe AD Bland emollients and parents/patient counseling
• Face (may include blepharitis and
— Eczematous plaques
• Generalized (may be erythroderma)
• In infants, the scalp (the frontal and parietal
scalp regions are covered with an oily-
looking, thick, often fissured crust -crusta
lactea (milk crust, or cradle cap) (Fig. 11.4),
face and diaper areas are often involved.
Leiner’s disease is due to complement C5
deficiency, presents as erythroderma.
• Clinically, adult patients develop erythema
and greasy scale on the scalp (with often
pruritus), paranasal areas, eyebrows,
nasolabial folds, central chest and
intertriginous folds (seborrheic areas of the
body). Rarely generalized lesions may occur.
Dandruff is usually the earliest manifestation
of seborrheic dermatitis.
• Course and prognosis— Atopic dermatitis
follows a highly variable course with
exacerbations and remissions. About 95% of
children with AD remit around puberty, but
relapses m ay occur and the disease may
persist well into adulthood.
SEBORRHEIC DERMATITIS (SD)
• Seborrheic dermatitis is a common,
endogenous eczema that is usually easily
• It affects infants and adults and is often
associated with increased sebum production
(seborrhea) of the scalp and the sebaceous
follicle–rich areas of the face and trunk.
• Various genetic factors, hormonal factors and
increased colonization of Malassezia may play
a role in the causation and perpetuation.
• Seborrheic dermatitis has two age peaks, one
in infancy within the first 3 months of life
and the second around the second to the third
decade of life. Men are affected more often
than women in all age groups.
Classification of Seborrhoeic Dermatitis
• Scalp (Cradle cap)
• Trunk (including flexures and napkin areas)
• Leiner’s disease.
Essentials in Dermatology104
• ‘Corona seborrheica’, when SD on the scalp
extends beyond the frontal hairline onto the
• Sebopsoriasis: Early stage of scalp psoriasis
may closely resemble seborrheic dermatitis
with similar clinical and histological features.
Some believe that seborrheic dermatitis may
be a precursor of scalp psoriasis.
• SD occur more commonly in variety of
medical disorders like parkinsonism,
myocardial ischemia, malabsorption,
epilepsy, obesity and alcoholic pancreatitis.
• SD can be a cutaneous marker of early HIV
infection (Fig. 11.5).
• Patients with HIV infection often have severe
• The disease is usually protracted over weeks
to months. The prognosis is good.
• Differential diagnosis:
1. HIV must be ruled out as patients with
HIV tend to have extensive/severe SD.
2. Scalp psoriasis: The lesions are well
defined, palpably thickened, brighter
pink in colour with silvery scales.
3. Infective dermatitis complicating
pediculosis may mimic SD.
4. Truncal SD should be differentiated from
pityriaisis rosea, tinea versicolor.
5. Flexural SD should be differentiated from
tinea, candidiasis, erythrasma.
6. Follicular SD should be differentiated
from Darier’s disease.
7. SD-like lesions can occur in acroder-
8. Drugs producing SD-like rash: Methyl
dopa, chlorpromazine, cimetidine.
• Treatment: In general, therapy is directed
towards loosening and removal of scales
(daily shampoo containing selenium sulfide,
zinc pyrithione, ketoconazole, cetavalon,
salicylic acid, coal tar; topical corticosteroids;
topical antifungals like imidazoles) and
Fig. 11.4: Seborrheic dermatitis-cradle
cap in an infant
Fig. 11.5: Seborrheic dermatitis in an adult–greasy
scaling with erythema involving eyebrows, nasolabial
folds and beard area in a HIV case
crusts, inhibition of yeast colonization,
control of secondary infection, and reduction
of erythema and itching. For unresponsive
cases, narrow band UVB, oral ketoconazole,
itraconazole or terbinafine may be used.
Other treatment modalities include topical
metronidazole (1%) gel, topical lithium
succinate, vitamin D 3 analogues, and oral
• Patients should be informed about the
chronic nature of the disease and understand
that therapy works by controlling the disease
rather than by curing it.
NUMMULAR ECZEMA (NE) (DISCOID
• The word nummular means (Latin
nummulus) –‘coin like’.
• Etiology of this is unknown.
• It mainly affects men aged 55-65 years.
• The eruption is characterized by pruritic,
coin shaped, eczematous lesions (Fig. 11.6)
• The lesion tends to develop on the extensor
surfaces of the extremities and trunk.
• Differential diagnosis: NE may simulate
tinea corporis (where scaling of the edge is
more conspicuous, scrapings shows presence
of mycelia). Exogenous dermatitis and
irritant dermatitis occasionally presents with
discoid response. In psoriasis, the lesions are
dry, the scaling is more prominent and the
irritation is milder.
• NE has a chronic course with frequent
• Treatment: open wet compresses, topical
steroids and antibiotics for secondary
• Pompholyx is characterized by itchy deep-
seated vesiculation on the palms and sides
of the fingers. Lesions appear ‘sago-like’.
• It may involve the soles of the feet.
• It occurs bilaterally symmetrically, has
• Differential diagnosis:
1. Id eruptions: Id eruptions are pompholyx-
like eruptions due to distant focus of
infections (e.g. kerion or bullous tinea
2. Pustular psoriasis of palms and soles:
Sterile pustules, absence of clear vesicles,
and characteristic residual brown marks
as the lesions subside
3. Pemphigoid lesions occurring on the
4. Bullous tinea pedis
• Treatment: open wet compresses, topical
steroids and antibiotics for secondary
• Pityriasis alba is a common disorder in
children that is characterized by an
asymptomatic, hypopigmented, slightly
elevated, fine, scaling plaque with
Fig. 11.6: Nummular eczema—coin shaped
eczematous lesions over the leg
Essentials in Dermatology106
• It usually disappears by adulthood.
• The condition commonly affects the face.
• Differential diagnosis:
1. Indeterminate leprosy: Lesion is usually
solitary to a few, hypopigmented macule
with ill-defined margins and equivocal
2. Tinea versicolor: Lesions are well-defined
hypopigmented macules with branny
scales. KOH examination shows
‘spaghetti and meatball’ appearance.
3. Vitiligo-early lesions may mimic but lack
4. Mycosis fungoides although relatively
rare may present with lesions clinically
resembling pityrasis alba.
• Treatment: Emollients, mild topical steroid
or topical pimecrolimus or tacrolimus
application may suffice.
• Stasis dermatitis occurs as a result of venous
stasis on the lower portions of the legs.
• The dermatitis may be acute, subacute or
• It differs from other forms of dermatitis,
firstly by showing brownish black
pigmentation and secondly, by resulting in
some instances in ulceration and atrophic
• The surrounding skin may show changes due
to venous stasis–hyperpigmentation,
induration of skin and lipodermatosclerosis
in late stage.
• Differential diagnosis:
1. Allergic contact dermatitis usually caused
by topical medications. Patch testing is
2. Infected ulcer with infective eczematoid
dermatitis around the ulcer responds to
appropriate antibiotic therapy.
3. Discoid eczema is common on lower legs
usually on the anterior or anterolateral
4. Asteatotic eczema commonly affects the
legs of elderly.
5. Dermatophyte infection may present as
diffuse erythema and scaling and can be
difficult to recognize, particularly if it has
been treated with topical steroids.
6. Psoriasis may present as a single irritable
plaque on the leg but is usually more scaly
and clearly marginated
· Treatment: The underlying venous
hypertension should be controlled. Well
fitted stockings can be helpful if worn
regularly. The legs should be elevated when
patient is recumbent. Topical steroids may
be used to relieve irritation.
ASTEATOTIC ECZEMA (ECZEMA
CRAQUELE, WINTER ECZEMA,
• It is an eczema associated with a decrease in
skin surface lipids.
• The eczema occurs after excessive drying,
especially during the winter months and
among the elderly and those with atopic
dermatitis or ichthyosis vulgaris.
• The skin of the limbs and trunk is
erythematous, dry and itchy and shows a fine
crazy-paving pattern of fissuring.
• Differential diagnosis: Atopic dermatitis,
various forms of ichthyosis especially
• Treatment: Central heating should be
humidified where possible. Avoidance of
frequent bath, use of synthetic detergent
instead of soap, regular lubrication of the skin
especially after bathing helps. Weak topical
steroids are often prescribed.
LICHEN SIMPLEX CHRONICUS
• Lichen simplex chronicus is characterized by
lichenified plaque lesion or lesions due to
repeated rubbing or scratching as a habit or
due to “stress”.
• Lichenification of the skin follows chronic
scratching and/or rubbing. This may occur
without a predisposing dermatosis, or may
follow any pruriginous dermatosis. The term
lichen simplex is used when there is no
• It is characterized histologically by acanthosis
and hyperkeratosis and clinically by
thickened appearance of the skin, with
accentuation of skin markings so that the
affected skin surface resembles tree bark.
• The areas most commonly affected are those
that are conveniently reached.
• These areas are ankles (Fig. 11.7) and wrists,
nape of neck (Fig. 11.8), genitalia (scrotum
or mons pubis) (Fig. 11.9), etc.
• It is common in Indian subcontinent amongst
adults (30-50 years).
• Differential diagnosis: The morphological
diagnosis of lichenification is not usually
difficult-lichen planus, lichen amyloidosis,
and psoriasis have to be excluded and typical
lesions sought in other sites.
• Treatment: Patient should be given some
assistance in reducing their tension. Sedation
is often needed and sedative antihistaminics
may be helpful. In most cases, a steroid cream
is the treatment of choice. To prevent the
scratching and to improve the outcome of the
treatment, steroid may be applied under
PRURIGO NODULARIS (PN, HYDE’S
• Prurigo is a Latin word for itching.
• PN is an intensely pruritic disorder in which
persistent rubbing and scratching in
particular area leads to formation of
distinctive hemispherical nodules with raised
warty surface (Fig. 11.10).
Fig. 11.7: Lichen simplex chronicus—thickening,
and pigmentation of ankle
Fig. 11.8: Lichen simplex chronicus—
involving nape of neck
Fig. 11.9: Lichen simplex chronicus-involving
female external genitalia
Essentials in Dermatology108
• Disease occur in 20-60 years of age, both sexes
are equally affected.
• The cause is unknown. The initial trigger for
itching in PN may include local trauma,
insect bite reactions and atopic eczema, etc.
• Differential diagnosis:
1. Hypertrophic lichen planus: Usually
violaceous, may be associated with
typical lichen planus lesions elsewhere.
2. Pemphigoid nodularis may present as
nodular prurigo for sometime before
typical urticated plaques and blisters
3. Allergic contact dermatitis may result in
4. Systemic causes of pruritus that can give
rise to lesions resembling nodular prurigo
include renal failure, liver disease,
lymphoma, and HIV infection.
• Treatment: Oral antihistamines, emollients,
topical steroids with salicylic acid and
intralesional steroids, cryotherapy, and
systemic agents such as thalidomide,
cyclosporine and azathioprine.
• It is an acquired self-limited inflammatory
linear skin disorder
• Exact etiology is unknown
• Children aged 5 to 15 years are commonly
• The most characteristic lesion is a linear band
of hypopigmented lichenoid papules that
follow Blaschko’s lines (Fig. 11.11)
• The lesions commonly occur on the arm or
• Course of the lesion may extend for 2 weeks
to 4 months.
• Differential diagnosis: Epidermal naevi
(persist indefinitely), linear lichen planus or
psoriasis (easily differentiated clinically, even
in the absence of typical lesions in other sites
which should always be sought for)
• Treatment: Usually none is necessary, topical
steroids, topical tacrolimus and intralesional
steroids in persistent cases.
Fig. 11.10: Prurigo nodularis—raised itchy nodular
lesions over the legs and dorsa of feet
Fig. 11.11: Lichen striatus—linearly arranged flat
topped papular lesions over the chest of a child
• Hand eczema is not a single diagnostic entity.
It is rather a morphological presentation of
various types of eczemas largely confined to
the hands and can have a multitude of factors
responsible for causing it, singly or in
combination. Causes of hand eczema are
broadly grouped into two groups as shown
1. Contact irritants: Chemicals (e.g. soaps,
Physical (e.g. friction, minor trauma, cold
2. Contact allergens: Delayed hypersensi-
tivity (e.g. chromium, rubber) Immediate
hypersentivity (e.g. seafood)
3. Ingested allergens (e.g. drugs, nickel,
4. Infection (e.g. bacterial infections of hand
5. Secondary dissemination (e.g. dermato-
phytide reaction to tinea pedis).
1. Idiopathic (e.g. Discoid, hyperkeratotic
2. Immunological or metabolic defects (e.g.
3. Psychosomatic: Stress aggravates, but
may not be causative
4. Dyshidrosis: Increased sweating aggra-
vates, but may not be causative.
Morphological types of Hand Eczema
2. Recurrent focal palmar peeling
3. Hyperkeratotic palmar eczema
4. Ring eczema
5. ‘Wear and tear’ dermatitis
6. Fingertip eczema
7. Apron eczema
8. Discoid eczema
9. Chronic acral dermatitis
10. Gut eczema.
• Differential diagnosis: The diagnosis of
hand eczema is usually self evident but
distinction from psoriasis is very difficult. In
most cases of psoriasis on hands, however,
the silvery nature of the scales, involvement
of knuckles, sharply demarcated scalloped
edges to the erythema along the borders of
the hands and fingers, and the relative
absence of pruritus are helpful pointers.
Family history of psoriasis and the presence
of nail pits in the absence of nail fold lesions
are also suggestive. Tinea can also be missed
especially when it is extensive and irritable
or secondarily infected. Unilateral scaling of
palm should always suggest tinea manuum.
• Treatment of hand eczema: Avoidance of
irritants, frequent application of emollients,
and sparing use of topical steroids.
JUVENILE PLANTAR DERMATOSIS
• Occurs mainly in children aged 3-14 years of
• The presenting features are redness and pain
on the plantar surface of the forefoot, which
assumes a glazed and cracked appearance.
• The condition is most severe on the ball of
the foot and toe pads, and tends to spare the
• The symmetry of the lesions is a striking
• Differential diagnosis: The toe clefts are
normal, and this helps to distinguish the
condition from tinea pedis. Patch testing to
exclude foot wear allergy may be done.
• Treatment: Most cases will clear
spontaneously during childhood or
Essentials in Dermatology110
adolescence. Patients are advised to use
emollients, 100% cotton socks and leather
shoes or sandals.
Contact dermatitis is an eczematous dermatitis
caused by exposure to substances in the
environment. Common types of contact
dermatitis are discussed here.
Irritant Contact Dermatitis (ICD)
• ICD is a non-immunological eczematous
reaction which occurs without previous
sensitization in most exposed individuals.
• Most common type of contact dermatitis.
• Common irritants include alkalis (soaps,
detergents), dye and ammonia containing
• The clinical features vary from mild xerosis
to erythema/chapping or even severe
ulceration depending on the concentration of
the irritant, the skin area exposed, mode of
contact and the substance itself.
• The reaction remains localized and does not
spread to become generalized and it does not
cause systemic symptoms.
• Acute irritant dermatitis is characterized by
vesicles and bullae (e.g. cement dermatitis,
savlon induced reaction).
• Chronic irritant dermatitis manifests as
hyperkeratosis, fissuring and scaling (e.g.
house wife dermatitis).
• Healing usually occurs within 2 weeks of
removal of noxious stimulus.
• In cases of chronic subcritical level of
irritation, some develop tolerance or
• Differential diagnosis: Same as for allergic
• Treatment: avoidance of irritants, use of
bland barrier creams, protective gloves and
mild topical steroids.
Allergic Contact Dermatitis (ACD)
• ACD results when an allergen comes in
contact with previously sensitized skin.
• It is a delayed hypersensitivity reaction,
consisting of sensitization phase and when
• Occurs in individual of all ages, especially
• Sensitization remains lifelong.
• The allergens are extremely varied and may
be nonprotein in nature.
• Common causes of ACD include plants,
nickel (Fig. 11.12), chromate, para phenylene
diamine (hair-dye) (Figs 11.13 and 11.14),
Fig. 11.12: Contact dermatitis—dermatitis over
abdomen due to trouser metallic hook
Fig. 11.13: Contact dermatitis—erythema and
edema due to acute dermatitis caused by hair dye
rubber compounds (Fig. 11.15), fragrances
and preservatives in compounds.
• The eczematous reactions develops at the
sites of skin contact with the allergen (Fig.
11.16) but occasionally spreads outside these
limits and cause systemic symptoms.
• The patch test is diagnostic and helps to
identify allergens involved.
• Patch test consists of application of
substances suspected to be the cause of the
contact dermatitis to the intact uninflammed
skin, in nonirritating concentration.
• Most common plant allergen in India is
• Most common metal causing ACD is nickel
• Differential diagnosis: Main differential
diagnostic consideration is irritant contact
dermatitis. Others are erysipelas (rapidly
spreading, non-pruritic, well defined
erythematous area, and patient is sick), atopic
dermatitis, nummular eczema, tinea (KOH
examination), seborrhoeic dermatitis,
polymorphous light eruption, and
• Treatment: The most important step is
avoidance of allergens. Acute dermatitis of
any sort is best treated with moist compresses
and high potency corticosteroid creams. In
severe cases, a short burst of systemic
corticosteroids tapered over 7-10 days is
needed. More chronic cases can be treated
with lower potency corticosteroids in an
ointment base. Oral cyclosporine is indicated
for therapy resistant chronic disease.
Fig. 11.14: Contact dermatitis—lichenoid dermatitis
over the forehead due to hair dye
Fig. 11.15: Contact dermatitis—dermatitis due to
Fig. 11.16: Common agents involved in contact
dermatitis of the face
Essentials in Dermatology112
DIFFERENCES BETWEEN IRRITANT CONTACT AND ALLERGIC CONTACT
Irritant contact dermatitis Allergic contact dermatitis
*People at risk Everyone Genetically predisposed
*Mechanism of response Nonimmunologic Delayed hypersensitivity
*Prior exposure required No Yes
*Nature of substance Organic solvents, soap Low molecular weight hapten
*Concentration of substance required Usually high May be low
*Symptoms Severe, stinging or burning sensation Pruritus
*Lesions Large tense bullae with necrosis Papules or papulovesicles
*Involvement of non-exposed sites No Yes
*Type of inflammatory cells Neutrophils Eosinophils and lymphocytes
*Patch test Not useful Diagnostic
Fig. 11.17: Infective dermatitis—oozing dermatitic
lesions behind ear and trunk
common, papulovesicular, eczematous,
erythematous, plaque like). Clinically, it
presents as non scarring, erythematous, itchy
papules, plaques or vesicles on exposed skin
that usually heal without scarring.
• The amount of light exposure needed to elicit
an eruption varies greatly from one patient
INFECTIVE DERMATITIS (INFECTIOUS
ECZEMATOID DERMATITIS, MICROBIAL
• Infective eczema is caused by micro-
organisms or their products, clears when
organisms are eradicated.
• It is seen predominantly around discharging
wounds or ulcers or moist skin lesions of
• It presents as an area of advancing erythema,
sometimes with microvesicles (Fig. 11.17).
• Treatment: Factors predisposing to infection
should be sought and when possible
eliminated. Wet compresses, topical
antibiotic in combination with steroid or
POLYMORPHIC LIGHT ERUPTION
• PMLE is the most common photodermatoses.
• The disease may begin at any age and the
symptoms are severe in spring and summer
• It is an idiopathic eruption caused by UV
exposure; appears in hours to days with
varied morphology (papular variant most
• Light sensitivity decreases with repeated sun
exposure, this phenomenon is referred to as
• Differential diagnosis: Lupus erythe-
matosus, photosensitive drug eruption,
prurigo nodularis, and photoallergic contact
dermatitis need to be differentiated.
• Treatment: Photoprotection by clothing and
sunscreens, phototherapy, and topical
steroids. In severe resistant cases, consider
the use of azathioprine 50-100 mg daily for 3
months. Use antioxidants, one week before
exposure may help in prevention.
Essentials in Dermatology114
12 Vesiculobullous Disorders
Vesiculobullous disorders cause significant
morbidity and mortality in dermatology. While a
with vesicles or bullae, two distinct groups of
disorders are the genetic blistering diseases
(epidermolysis bullosa) and the acquired
autoimmune blistering disorders (pemphigus,
bullous pemphigoid, dermatitis herpetiformis,
chronic bullous dermatosis of childhood,
epidermolysis bullosa acquisita).
Vesiculobullous disorders are diseases where
the primary lesion is a vesicle or bulla. It occurs
due to pathology in the epidermis or dermo-
epidermal junction or dermis. In this chapter we
are not dealing with secondary causes of
vesiculation like to burns, suction blisters,
ischemia leading to blisters (vasculitis, diabetic
bulla), drug eruptions like bullous fixed drug
eruption, insect bite reaction, infections (varicella,
herpes simplex, herpes zoster), dermatitis,
miliaria, etc. This chapter would discuss primary
vesiculobullous disorders. In epidermal auto-
immune vesiculobullous disoders, the
mechanism behind blister formation is primarily
acantholysis in most cases. Decreased stability of
basement membrane is responsible for a variety
of subepidermal vesiculobullous disoders which
could be either inherited or of acquired
1. Inherited/genetic blistering disorders:
a. Epidermolysis bullosa simplex
b. Junctional epidermolysis bullosa
c. Dystrophic epidermolysis bullosa.
2. Acquired autoimmune blistering disorders:
a. Intraepidermal immunobullous diseases
1. Pemphigus vulgaris and its variant
2. Pemphigus foliaceous and its variants
i. Endemic pemphigus foliaceus (Fogo
selvagem; wild fire).
ii. Pemphigus erythematosus (Senear-
3. Drug induced pemphigus.
4.. IgA pemphigus
i. Intraepidermal neutrophilic type
ii. Subcorneal pustular dermatosis type.
5. Paraneoplastic pemphigus.
6. Subcorneal pustular dermatosis (Sneddon
3. Subepidermal immunobullous diseases
a. Bullous pemphigoid and its variants
b. Mucous membrane pemphigoid (cica-
Vesiculobullous Disorders 115
c. Pemphigoid gestationis (Herpes gesta-
d. Linear IgA disease/Chronic bullous
dermatosis of childhood
e. Dermatitis herpetiformis
f. Epidermolysis bullosa acquisita
g. Bullous systemic lupus erythematosus.
The following discussion deals with these two
• Epidermolysis bullosa (EB) comprises a group
of genetically determined skin disorders
characterized by blistering of the skin (Fig.
following mild mechanical trauma (due to
increased fragility of skin). Thus an alternative
term for these disorders could be the
• There are three main types of EB:
– EB simplex (intraepidermal split due to
disruption of basal keratinocytes)
– Junctional EB (split through the basement
– Dystrophic EB (split in the subepidermal
• EB simplex is the commonest and mildest
form of EB of autosomal dominant
inheritance. It is characterized by onset of
blistering over trauma prone sites at birth or
infancy. Lesions heal without scarring.
Mucosae, nails and hair are essentially
• Junctional EB are autosomal recessive
disorders and are broadly classified into two
main types, the lethal and non-lethal forms.
They present at birth or soon after with severe
fragility of the skin leading to extensive
blistering and denudation. Oropharyngeal
be malformed and prematurely lost and nails
may be shed. This is the most fatal type of EB.
• Dystrophic EB is characterized by skin
fragility, scarring with milia (Fig. 12.2), nail
changes(Fig. 12.3)and have either autosomal
recessive or dominant inheritance. The more
severe autosomal recessive form is
Fig. 12.1: Epidermolysis bullosa—baby showing
Fig. 12.2: Epidermolysis bullosa dystrophica–knee
showing hemorrhagic bullae with scarring, milia and
Essentials in Dermatology116
– Onset at birth or early infancy
– Oral blisters and scarring leading to
ankyloglossia and microstomia
– Esophageal lesions causing painful
dysphagia and later esophageal strictures.
– Perianal blistering, erosions and scarring
causing stenosis and fecal retention.
– Ocular complications—symblepharon,
corneal erosions and opacity
– Repeated blistering and progressive
scarring—contractures and deformities
(e.g. ‘Mitten hands’).
• Diagnostic techniques include skin biopsy,
electron microscopy to ascertain the level of
split and structures involved, antigen
mapping and immunohistochemistry. No
autoantibodies are demonstrated in the sera.
Prenatal DNA testing can be advised to
couples at risk of having affected children.
• No specific treatment is available for EB and
thus the mainstay of treatment is based on
avoidance of provoking factors. Management
of the neonate includes maintaining adequate
nutrition and hydration and prevention of
sepsis. Other aspects include care of the oral
cavity, teeth, eyes and management of contra-
ctures and deformities.
• Gene therapy appears as a realistic goal in
• Pemphigus is derived from the Greek
‘pemphix’ meaning blister or bubble and is
characterized by intraepidermal blistering at
various levels in the epidermis.
• The key pathogenic process in this group of
disorders is disruption of the intercellular
cementing substance due to an autoantibody
attack on the cellular adhesion proteins
(desmogleins) leading to acantholysis.
• The pemphigus group of disorders includes
two major types (and their variants) and
– Pemphigus vulgaris (variant – Pemphigus
vegetans): level of split-suprabasal.
– Pemphigus foliaceus (variant – Pem-
phigus erythematosus): level of split –
• The other minor types of pemphigus include
paraneoplastic pemphigus, drug induced
pemphigus, IgA pemphigus and neonatal
for up to 80% of pemphigus cases. Occurs at
decades. In India, it occurs at younger age.
• It is due to IgG antibodies directed against
epidermal cell adhesion molecules
(desmoglein 3)- disruption of intercellular
cementing substance—loss of adhesion
between epidermal cells (acantholysis)
• Almost all patients have mucosal lesions,
50–70% present with painful oral erosions.
Lesions may be limited to oral cavity for
months to one year (Fig. 12.4).
Fig. 12.3: Epidermoloysis bullosa dystrophica–
albopapuloid lesions over the dorsa of feet and some
of the toenails completely lost
Vesiculobullous Disorders 117
• Skin – flaccid bullae on normal or erythe-
matous skin, with a predilection for scalp,
face (Fig. 12.5), trunk (Figs 12.6 and 12.7),
axillae and groins and pressure sites.
Bullae rupture producing painful erosions
• Pruritus is absent or negligible.
• Nikolsky’s sign and Bulla spread sign
(Asboe-Hansen sign) are positive. (Other
disorders with positive Nikolsky’s sign are
staphylococcal scalded skin syndrome, toxic
epidermal necrolysis, etc.).
• Other mucosae involved are conjunctiva,
pharynx, larynx, oesophagus, urethra, vulva
Fig. 12.4: Pemphigus vulgaris—painful erosions
involving tongue and lips
Fig. 12.5: Pemphigus vulgaris—extending
erosions without tendency to heal over the face
Fig. 12.6: Pemphigus vulgaris—involving chest Fig. 12.7: Pemphigus vulgaris—involving back
Essentials in Dermatology118
• Prognosis is poor without treatment but with
systemic steroids mortality has been reduced
to 5–15 %.
• Pemphigus may be associated with other
autoimmune diseases such as thymoma,
myasthenia gravis and malignancies like
lymphomas and bronchogenic carcinoma.
• Tzanck smear from the floor of the blister
shows acantholytic cells. Acantholytic cell is
a large, rounded epidermal cell with a large
nucleus, perinuclear halo and peripheral
condensation of cytoplasm (Fig. 12.8).
• Histopathological examination of a blister
shows a supra-basal cleft in the epidermis.
The basal keratinocytes remain attached to the
basement membrane but are separated from
each other and stand like a ‘row of
• Immunofluorescence studies are the gold
standard in diagnosis of the autoimmune
blistering disorders. In pemphigus vulgaris,
direct immunofluorescence done on the
lesional skin shows deposition of intercellular
IgG throughout the epidermis in a ‘fish-net’
pattern (Fig. 12.9). Indirect immuno-
fluorescence done to determine levels of
pathogenic antibodies in the sera of the
patients shows circulating intercellular IgG
antibodies in 80–90% of the cases. Levels of
these antibodies correlate with disease
It is a clinical variant of pemphigus vulgaris
characterized by vegetating lesions primarily in
the flexures (Figs 12.10 and 12.11). Initial lesions
are bullae or pustules, which rupture and
progress to form vegetating plaques.
• This disorder, characterized by blistering at a
higher level in the epidermis is less common
than pemphigus vulgaris and accounts for
only 15–20 % of pemphigus cases.
• It is caused by IgG antibodies directed
against intercellular adhesion molecules
(desmoglein 1) found predominantly in the
upper epidermis—disruption of intercellular
subcorneal blister formation.
• Clinically, pemphigus foliaceous is less severe
than pemphigus vulgaris and is characterized
by crusted, moist, scaly lesions in a
seborrheic distribution (Fig. 12.12) involving
scalp, face, chest and upper back. Blistering
may not be obvious due to the superficial level
of the split (very transient nature of blisters).
Fig. 12.8: Tzanck smear showing large rounded
epidermal cells with large nuclei, perinuclear halo
and peripheral condensed cytoplasm (Acantholytic
Fig. 12.9: Direct immunofluorescence
showing fish net pattern
Vesiculobullous Disorders 119
• Oral lesions are uncommon.
• Nikolsky’s sign is invariably positive
• Tzanck smear from fresh erosion shows
• Histology shows a subcorneal cleft with
• Immunofluorescence findings are usually
indistinguishable from pemphigus vulgaris.
Prognosis of this disorder is better than
pemphigus vulgaris. This benign disorder
responds well to treatment.
Fig. 12.10: Pemphigus vegetans—vegetating moist
lesions occurring in the axilla
Fig. 12.11: Pemphigus vegetans—vegetating moist
lesions in the retroauricular area
Fig. 12.12: Pemphigus foliaceous—moist scaly
lesions in seborrheic areas of the face
Fig. 12.13: Nikolsky’s sign – tangential pressure with
finger tip producing moist erosion due to peeling of
Essentials in Dermatology120
It is a variant of pemphigus foliaceous charac-
terized by immunological features of both
pemphigus and lupus erythematosus (LE), that
is, intercellular IgG and C3 in the epidermis (as
in pemphigus) and in the basement membrane
zone (as in LE) and antinuclear antibodies (as in
LE). Clinically, erythematous, scaly rash over the
nose and cheeks simulate LE while lesions on the
Other Variants of Pemphigus
• Endemic pemphigus foliaceous (Fogo
Selvagem) is a variant of pemphigus
foliaceous, endemic to certain parts of South
America and is postulated to be precipitated
by bites of the black fly (Simuliidae). The burnt
appearance and burning sensation gave the
disease its name, fogo selvagem, meaning
• Drug induced pemphigus (penicillamine,
captopril, pyritinol, penicillin, rifampicin)—
clinically commonly present as pemphigus
• Paraneoplastic pemphigus—a polymor-
phous blistering eruption with muco-
cutaneous ulcerations having an underlying
• Pemphigus herpetiformis—superficial
vesicles and inflammatory papules occur in
• IgA pemphigus—has bound and circulating
IgA autoantibodies against intraepidermal
cell surface antigens and clinically may
resemble subcorneal pustular dermatosis.
• Juvenile pemphigus— pemphigus occurring
before 20 years of age
• Neonatal pemphigus— due to transplacental
transfer of maternal anti-intercellular cement
substance antibodies to the fetus. Blisters
resolve in 2 weeks.
When skin is involved, other autoimmune
vesiculobullous disorders need to be differen-
impetigo, dyskeratotic acantholytic disorders
(Darier’s disease, Hailey Hailey disease, Grover’s
disease) can cause a problem.
When only the oral mucosa is involved, the
following should be considered-aphthous
ulcerations, oral erosive lichen planus, herpetic
gingivostomatitis, erosive candidiasis, and
Johnson syndrome, toxic epidermal necrolysis,
bullous systemic lupus erythematosus, and
generalized bullous fixed drug eruption.
Treatment of Pemphigus
• The mainstay of therapy in the pemphigus
group of disorders is with systemic steroids,
which can be given as conventional therapy
(oral prednisolone in the dose of 1 mg per kg
body weight) or as pulse therapy. An
upcoming mode of therapy is the dexa-
methasone cyclophosphamide pulse regimen
consisting of 100 mg of IV dexamethasone in
5% dextrose infusion on 3 consecutive days
of each month combined with IV cyclopho-
sphamide 500 mg bolus dose on day 1 of the
pulse and oral cyclophosphamide 50 mg daily
on other days. This therapy reduces the
conventional side effects of steroids.
• The other modalities of therapy include
adjuvant therapy with dapsone, azathioprine,
cyclosporine, methotrexate, gold salts,
mycophenolate mofetil, intravenous
immunoglobulin therapy and plasmapheresis
and are essentially to reduce the side effects of
steroids or to control the severe form of
Vesiculobullous Disorders 121
BULLOUS PEMPHIGOID (BP)
• Autoimmune subepidermal blistering
60 years of age.
• Basic pathogenic process is due to IgG
antibodies against components of the
basement membrane zone (BMZ – structure
which binds epidermis to the underlying
dermis and mesenchyme)— loss of structural
integrity of the BMZ due to resultant
inflammation separation of the intact
epidermis from underlying dermis-
subepidermal cleft formation.
• Preceded by pruritus with or without
urticarial wheals lasting usually for 1–3
• Tense bullae on normal or erythematous
skin predominantly over flexural aspects of
the limbs (Fig. 12.14), lower abdomen
(Fig. 12.15), groins and axillae. Facial skin
and scalp relatively spared.
– Lesions rupture to leave erosions that heal
spontaneously with postinflammatory
– Nikolsky’s sign usually negative; Bulla
spread sign +/-
– Mucosal lesions rare and less severe than
in pemphigus vulgaris and almost never
the presenting feature.
• Bullous pemphigoid may be associated with
an underlying malignancy(gastric carcinoma
commonly) and may be associated with
diabetes mellitus, rheumatoid arthritis and
• Tzanck smear will show numerous
eosinophils with few neutrophils but no
• Histopathological examination reveals
subepidermal cleft with intact epidermis
forming the roof of the blister.
• Direct immunofluorescence of perilesional
skin shows linear IgG (45–90%) and C3
(80–100 %) deposition in the basement
membrane zone. Indirect immunofluo-
rescence studies done on the patient’s sera
show circulating IgG autoantibodies in most
cases but unlike in pemphigus, their titers do
not correlate with disease activity.
Fig. 12.14: Bullous pemphigoid—itchy urticarial
lesions over the thigh developing into tense bullae
Fig. 12.15: Bullous pemphigoid—involving
Essentials in Dermatology122
Bullous pemphigoid can be easily differentiated
IgA disease, chronic bullous disease of childhood,
dermatitis herpetiformis, erythema multiforme
and pemphigus by histology and immuno-
fluorescence. Most difficult diseases to
differentiate from bullous pemphigoid are
epidermolysis bullosa acquisita and cicatricial
• Prognosis of bullous pemphigoid is better
than pemphigus and it runs a chronic self-
limiting course. It may be fatal in the active
stage in the elderly or debilitated patients.
• The mainstay of treatment is a topical or
systemic steroid depending on the severity
of the disease. Pulse dexamethasone
cyclophosphamide, methyl prednisolone or
cyclophosphamide pulse may be used. Other
modalities include cyclophosphamide,
azathioprine, dapsone, tetracycline with
nicotinamide, erythromycin, leflunomide,
sulphapyridine, methotrexate, mycopheno-
late mofetil, intravenous immunoglobulin
therapy and plasmapheresis.
Clinical Variants of Bullous
• Cicatricial pemphigoid is a rare blistering
disorder of the mucosa and skin that results
in permanent scarring of the affected area.
Mucosal lesions predominate and involve in
decreasing order the oropharynx (Fig. 12.16),
nasopharynx, conjunctiva, larynx, genitalia
and esophagus. Sequelae include oropha-
ryngeal adhesions, esophageal strictures,
stridor, introital shrinkage, symblepharon
(Fig. 12.17) and ‘statue eye’. Unlike bullous
pemphigoid, this disorder is not self-limiting
and has a chronic debilitating course.
blistering disease of young women that
occurs in pregnancy (21–28 weeks of
gestation) or within 1st week postnatally.
Clinically, the disease starts as severe pruritus
with urticarial wheals and plaques followed
by blistering predominantly in the
periumbilical area, lower abdomen and
thighs. Mucosal involvement is rare and
lesions improve postpartum. Recurrence may
occur in subsequent pregnancies, premen-
strually or with oral contraceptive pills
(OCPs). Direct immunofluorescence shows
Fig. 12.16: Cicatricial pemphigoid—
tense bulla over the tongue
Fig. 12.17: Cicatricial pemphigoid—face showing
Vesiculobullous Disorders 123
Characteristic Bullous pemphigoid Pemphigus vulgaris
Age > 60 years Middle age
Pruritus ++ Not present
Blister Tense Flaccid
Sites Flexures, groins, axillae, abdomen Face, scalp, trunk, pressure points
Erosion Spontaneously heal Extend peripherally
Nikolsky’s sign Negative Positive
Oral lesions 40 % less severe, almost never a 80–90 % severe commonly the
presenting feature presenting symptom
Prognosis Benign, self limiting Poor without treatment
DERMATITIS HERPETIFORMIS (DH)
• DH is defined as an intensely pruritic,
chronic, recurrent, papulovesicular disease
with an underlying gluten-sensitive
enteropathy which may be asymptomatic.
• Onset at any age, usually between 20–55 years
• Males outnumber females.
followed by a symmetrical eruption of
erythematous papules and papulovesicles,
which are so rapidly excoriated that intact
vesicles are difficult to demonstrate
• Sites – extensor aspects of limbs (elbows and
knees), buttocks, natal cleft, shoulders, upper
back (Fig. 12.19), face and scalp. Grouping of
lesions accounts for it being described as
herpetiformis (not associated with herpes
• Oral lesions are common but asymptomatic.
• Provocation of lesions occurs with iodides
orally or in iodide patch testing.
• Histologicalexamination bestdoneonlesions
neutrophilic microabscesses at the tips of
Fig. 12.18: Dermatitis herpetiformis—extremely itchy
tense grouped vesicular lesions over the shoulder
Fig. 12.19: Dermatitis herpetiformis—bilateral
symmetrical distribution of itchy eroded lesions over
the extensor aspect of limb and trunk
Essentials in Dermatology124
• Direct immunofluorescence is the most
reliable diagnostic criterion and should be
performed on clinically normal skin
IgA deposits in dermal papillae.
• Indirect immunofluorescence is negative for
anti-BMZ or dermal autoantibodies but
antithyroid and antigliadin antibodies may
Dermatitis herpetiformis can be confused with
numerous conditions because of its pleomorphic
manifestations and occasional lack of diagnostic
lesions. Scabies, bullous pemphigoid before the
development of blisters, and the prurigo group of
disoders are the main issues. It also needs to be
differentiated from chronic exudative eczema,
papular urticaria, neurotic excoriations, and
transient acantholytic dermatoses. A high index
of suspicion is very helpful, even in the absence
of primary lesions. Dermatitis herpetiformis can
be diagnosed based on the typical in vivo bound
granular IgA deposits in normal appearing skin.
• Dapsone 100–200 mg/day (up to 400
mg /day) is the drug of choice. It is amazingly
effective; hours to days after the first dose, the
pruritus disappears and no new lesions erupt
after 1-2 days of treatment.
• Strict adherence to a gluten-free diet for
prolonged periods (e.g. 6 to 12 months) may
control the disease in some patients, obviating
or reducing the requirement for drug therapy.
LINEAR IgA DISEASE
It is a chronic acquired subepidermal blistering
disorder of children and adults, with skin and
mucous membrane involvement and charac-
terized by linear deposition of IgA at basement
membrane zone. It consists of two main entities-
chronic bullous disease/dermatosis of childhood
(CBDC), with onset in childhood and linear IgA
disease which presents in adults. There is lot of
overlap in the clinical presentation of the two
entities but they differ in their age at presentation
and few clinical signs.
In linear IgA disease, periorificial and annular
lesions are not as common as in CBDC.
Hemorrhagic bullae may be present.
Chronic Bullous Disease/dermatosis of
Childhood (CBDC, Linear IgA disease of
• CBDC is defined as a chronic acquired
autoimmune subepidermal blistering disease
of children characterized by IgA BMZ
• Onset is usually at around 5 years of age
(toddlers and preschool children).
• Urticarial plaques with blistering at the
edges – ‘string of pearls’ appearance and
localization of lesions around orifices
(perioral, perigenital) (Figs 12.20 and 12.21).
Fig. 12.20: Chronic bullousdermatosis of childhood—
clustering of tense bullae around the mouth
Vesiculobullous Disorders 125
• Spontaneous remission usually occurs with
• Direct immunofluorescence shows linear
IgA at BMZ.
In young infant, bullous impetigo may resemble
the initial lesions, but its response to antibiotics
differentiates it. Epidermolysis bullosa often
present at birth and family history further
differentiates it. Bullous papular urticaria rarely
affects the face or genital region and it is usually
of short duration. Childhood bullous pemphigoid
may give us similar clinical picture but the
deposition of IgG and C3 at the BMZ is diagnostic.
Treatment is the same. Dermatitis herpetiformis
only occurs in small children (usually occurs
between 20 and 55 years of age) who are
heterozygous for predisposing HLA genes.
• Dapsone is usually effective (response usually
occurs within 24-48 hours), and may be
combined with low dose steroids in refractory
Disorder Site of split Pathogenic
P. vulgaris Suprabasal IgG
P. foliaceous/ Subcorneal IgG
Paraneoplastic Suprabasal IgG
BP / HG / CP Subepidermal IgG and C3
EBA Subepidermal IgG
Dermatitis Subepidermal IgA
CBDC Subepidermal IgA
(Note: Epidermolysis bullosa are a group of
genetic disorders with structural defects but NO
• It is defined as a chronic, acquired
autoimmune blistering disorder characterized
either by trauma-induced subepidermal
blistering or with a clinical picture
indistinguishable from bullous pemphigoid.
• IgG class of autoantibodies directed against
component of the anchoring fibrils found in
the subepidermal zone; (differentiate from
hereditary epidermolysis bullosa dystrophica
in which there is a collagen VII structural
defect leading to reduced or absent collagen
VII in the anchoring fibrils).
The five clinical presentations of EBA are:
1. Classical presentation– Noninflammatory
tense bullae over trauma prone areas which
heal with scarring and milia formation.
Hemorrhagic bulla may be seen. It is a
mechanobullous disease marked by skin
2. Bullous pemphigoid–Like presentation–
widespread inflammatory vesiculobullous
eruption over trunk, flexures and extremities.
Fig. 12.21: Chronic bullous dermatosis of childhood–
lower limbs showing “cluster of jewels” appearance
at many sites
Essentials in Dermatology126
Tense bullae are present over inflamed or
urticarial skin. Hemorrhagic bulla may be
seen. Large areas of erythema and urticaria
without blistering can be seen. Patient
complains of pruritus and does not show
prominent skin fragility, scarring or milia
formation. The clinical picture is more like a
bullous pemphigoid than a mechanobullous
3. Cicatricial pemphigoid-like presentation– is
marked by widespread mucosal involvement.
Clinical appearance is similar to cicatricial
pemphigoid. Erosions and scars over mucosal
surfaces of mouth, upper esophagus,
conjunctiva, anus or vagina are present with
or without similar lesions over glabrous skin.
4. Brunsting-Perry pemphigoid-like presen-
tation– is a chronic recurrent vesiculobullous
eruption localized to head and neck. It is
characterized by bullae healing with scarring
and has minimal to no mucosal involvement.
5. IgA bullous dermatosis-like eruption– is
characterized by tense veskcles arranged in
an annular pattern and mucous membrane
involvement. It is also differentiated from
other EBA types by its DIF findings of linear
deposition of IgA at basement membrane
• Histology shows subepidermal cleft with
neutrophilic infiltrate in the BP type while
sparse inflammatory infiltrate in the
• Direct immunofluorescence (DIF) on
perilesional skin shows thick polyclonal band
of deposition of IgG and C3 and sometimes
IgA and IgM in the BMZ.
• DIF on salt split skin shows deposits of IgG
and C3 on dermal side whereas in bullous
pemphigoid in 85% cases deposits are present
on epidermal side and in 15% cases, it may be
seen on both epidermal and dermal sides.
• EBA is a very difficult disease to treat. Steroids
in combination with dapsone or adjuvant
immunosuppressives (azathioprine, metho-
trexate, cyclophosphamide, cyclosporine,
high doses of colchicine) are the usual line of
therapy. Photopheresis and intravenous
immunoglobulin have been used. The
mechanobullous type is resistant to most
modalities of treatment. Supportive therapy
is warranted in all patients with EBA. This
includes instructions in open wound care and
strategies in avoiding trauma.
Cutaneous Tuberculosis and Atypical Mycobacterial Infections 127
13 Cutaneous Tuberculosis and
Atypical Mycobacterial Infections
Tuberculosis of the skin constitutes about 10% of all extra-pulmonary tuberculosis which in turn
constitutes only a fraction of all cases of tuberculosis.
CLASSIFICATION OF CUTANEOUS TUBERCULOSIS (TB)
Types Mode of infection Bacilli Immunity Tuberculin
* TB chancre Inoculation +++ - -
*Miliary TB Hematogenous ++ - -
*Lupus vulgaris Inoculation +/- +++ +++
*TBVC Inoculation + +++ +++
*Scrofuloderma Contiguous ++ +++ ++
*TB gumma Hematogenous ++ + +
*Orificial TB Autoinoculation ++ + -
*Papulonecrotic Hematogenous - +++ +++
*Lichen scrofulosorum “ - +++ +++
*Erythema induratum “ - +++ +++
Cutaneous Tuberculosis can be
Classified as Given Blow
1. Inoculation tuberculosis (exogenous source):
a. Tuberculous chancre
b. Tuberculosis verrucosa cutis
c. Lupus vulgaris (some).
2. Secondary tuberculosis (endogenous source)
a. Contiguous spread— scrofuloderma
b. Autoinoculation— orificial tuberculosis.
3. Hematogenous tuberculosis— acute miliary
tuberculosis, lupus vulgaris (some),
4. Eruptive tuberculosis (tuberculids)
a. Micropapular— lichen scrofulosorum
b. Papular— papular or papulonecrotic
c. Nodular— erythema induratum of Bazin,
Essentials in Dermatology128
It occurs due to inoculation of M. tuberculosis into
the skin of an individual without natural or
acquired immunity to tubercle bacilli.
• Usually seen in face or limbs of children
• Presents as a brownish red papule or nodule
that ulcerates to form a ragged ulcer with
• Associated with regional lymphadenopathy
• If untreated, chancre heals slowly over
Miliary TB occurs due to hematogenous
dissemination of tuberculosis in infants and
children or immunosuppressed
• The skin lesions are varied— may manifest as
crops of bluish papules, vesicles, pustules or
• Diagnosis established by skin biopsy which
shows acid fast bacilli
• The primary source of TB should be identified
It is the most common type of progressive
cutaneous tuberculosis occurring in people with
moderate or high immunity.
• Lupus vulgaris arises from normal skin but it
can arise in a scar of scrofuloderma.
• The initial lesion is a reddish-brown, soft,
gelatinous plaque which increases in size and
• Peripheral extension occurs with resultant
scarring (Figs 13.1 and 13.2).
• Diascopy reveals ‘apple jelly’ nodules in the
• The various morphological forms are plaque
type, ulcerative and mutilating form,
vegetative form and tumor like.
• Nasal mucosa can be involved leading to
resultant destruction of nasal septum.
• Rarely squamous cell carcinoma can occur.
• Discoid lupus erythematosus— Lesions begin
as dull red macules or indurated plaques that
develop an adherent scale (carpet tack sign),
mainly over head and neck and evolve with
atrophy, scarring and pigmentary changes.
Fig. 13.1: Lupus vulgaris—plaque lesion with active
infiltrated border with central scarring over the thigh
Fig. 13.2: Lupus vulgaris—verrucous plaque with
trailing scar and depigmentation in the groin
Cutaneous Tuberculosis and Atypical Mycobacterial Infections 129
• Lupoid form of cutaneous leishmaniasis may
be impossible to distinguish clinically.
Histopathology distinguishes them.
• Deep mycoses may resemble vegetating form
of lupus vulgaris. It can be differentiated by
histology and culture reports.
• Leprosy— nodules of leprosy are firmer
compared to those of lupus vulgaris. Other
signs of leprosy would help in distinguishing
it from lupus.
• Sarcoidosis— nodules of sarcoidosis resemble
grains of sand on palpation and the surface is
shiny and waxy.
• Psoriasis - usually multiple lesions over the
extensor aspect of limbs and lumbosacral
areas, but are less infiltrated compared to
lupus vulgaris. They are associated with
silvery white micaceous scales and there is
no evidence of scarring.
• Lichen simplex chronicus of perianal area
may mimic lupus vulgaris. There will be no
scarring and it will be itchy and hyper-
pigmented rather than reddish brown in
TUBERCULOSIS VERRUCOSA CUTIS
(WARTY TUBERCULOSIS, ANATOMIST’S
Tuberculosis verrucosa cutis (TBVC) manifests as
a warty growth that occurs as a result of
inoculation of mycobacteria into the skin of a
previously infected individual with moderate to
• Lesions occur in exposed areas such as foot
(Figs 13.3 and 13.4), hand, ankle and rarely
• The lesions start as warty papules that enlarge
• TBVC should be differentiated from other
warty lesions such as verruca vulgaris, lupus
vulgaris (usually not hyperkeratotic, diascopy
demonstrates apple jelly nodules), chromo-
blastomycosis, hypertrophic lichen planus
(has multiple itchy lesions usually over lower
legs with evidence of lichen planus
elsewhere), leishmaniasis and tertiary
Scrofuloderma results from breakdown and
such as lymph node, bone, joint, epididymis or
• It manifests as bluish red nodules overlying
undermined ulcers with a bluish edge (Figs
13.5 and 13.6).
Fig. 13.3: Tuberculosis verrucosa cutis—verrucous
plaque with fissuring and foetid discharge over the
Fig. 13.4: Tuberculosis verrucosa cutis—verrucous
plaque with fissuring over the dorsum of great toe
Essentials in Dermatology130
• The resultant sinuses and fistulae heal with
puckered scarring (Fig. 13.7).
• Scrofuloderma should be differentiated from
hidradenitis suppurativa, acne conglobata,
syphilitic gumma and actinomycosis.
Cervicofacial actinomycosis is characterized
by multiple sinuses, puckered scarring and
formation of new nodules that lead to an
uneven indurated lumpy surface. Pus
containing sulphur granules discharging from
multiple sinuses is quite characterstic,
distinguishing it from scrofuloderma.
TUBERCULOUS GUMMA (METASTATIC
It occurs due to hematogenous dissemination
during periods of bacillemia and lowered
• Common in poorly nourished children
• Presents as firm subcutaneous nodules that
Tuberculosis of mucosa or skin adjoining orifices
in a patient with advanced internal tuberculosis
is known as orificial TB (Fig. 13.8).
• The affected patient is usually an adult of poor
Fig. 13.5: Scrofuloderma—subcutaneous nodules
and ulcerated lesions along with scarring in the neck
Fig. 13.6: Scrofuloderma—ruptured bluish nodules
with undermined edges in the axilla
Fig. 13.7: Scrofuloderma—sinuses and fistulae
healing with puckered scarring over the back
Cutaneous Tuberculosis and Atypical Mycobacterial Infections 131
• Lesions occur in the mouth, tongue, or
genitalia as reddish nodules that break down
to form painful shallow ulcers with bluish
Tuberculids are hypersensitivity eruptions which
arise in response to an internal focus of
tuberculosis and clear with antituberculous
• It is an eruption of necrotizing papules,
particularly affecting extremities and
occurring in more or less symmetric crops.
• The lesions are hard, dusky papules that crust
or ulcerate to heal with atrophic scars (Fig.
• Papulopustular secondary syphilis, pityriasis
lichenoides et varioliformis acuta, Churg-
Strauss granuloma, lymphomatoid papulosis,
perforating granuloma annulare, perforating
collagenosis and necrotizing or septic
vasculitis share clinical and histologic
features with papulonecrotic tuberculid.
• It presents as grouped, closely set minute
perifollicular papules over the trunk (Fig.
13.10) or extremities in children with
• Lichen nitidus, lichen planus, secondary
syphilis and sarcoidosis should be considered
in the differential diagnosis.
• Presents as persistent or recurrent
erythematous tender nodular lesions
(Fig, 13.11) (usually ulcerate in contrast to
erythema nodosum) that occur secondary to a
tuberculous focus elsewhere.
• The lesions are localized to legs (calf region)
of middle aged women with erythrocyanotic
• It must be distinguished from erythema
nodosum (short duration, rapid development,
affects chiefly anterior aspect of the leg, more
painful tender nodules that do not ulcerate),
nodular vasculitis, polyarteritis nodosa,
tertiary syphilis (gumma is usually unilateral
and single, serology and histology helps), and
other infectious and inflammatory
• Positive culture for M. tuberculosis
• Guinea pig inoculation
• PCR for M. tuberculosis.
• Proven TB elsewhere in the body
• Presence of AFB in the lesion
• Positive tuberculin test (Fig. 13.12)
• Clinical history and physical signs
• Response to therapy.
Fig. 13.8: Orificial tuberculosis—painful, shallow
ulcers with undermined edges around the anus
Essentials in Dermatology132
Fig. 13.9: Papulonecrotic tuberculid—atrophic scars
over the thigh following papulonecrotic tuberculid
Fig. 13.10: Lichen scrofulosorum—micropapular
eruption over the trunk
Fig. 13.11: Erythema induratum—erythematous
indurated tender noduloplaque lesion over the leg
Fig. 13.12: Positive Mantoux reaction
Anti tubercular therapy with three or four drugs
is given for a period of 6 to 9 months based on the
type of tuberculosis. Most regimens contain
isoniazid, rifampin, ethambutol and pyrazi-
Atypical mycobacteria can present with varied
cutaneous features in normal as well as
immunosuppressed patients. The main features
are summarized in the following table.
Cutaneous Tuberculosis and Atypical Mycobacterial Infections 133
SUMMARY OF ATYPICAL MYCOBACTERIAL INFECTIONS
Organism Disease Clinical Features Treatment
M.marinum Swimming pool granuloma, Warty plaque or sporotrichoid Rifampin and ethambutol or
fish tank granuloma lesions on knees, elbows and tetracycline
M.ulcerans Buruli ulcer Subcutaneous nodules rupture Surgery is the treatment of choice
to form shallow ulcers with followed by rifampin or
necrotic fat in the floor cotrimoxazole
M.avium complex Nodules, leg ulcers and papules Combined therapy of isoniazid,
Disseminated heterogenous rifampin and streptomycin.
infection in HIV patients
M.chelonae Injection Cellulitis and subcutaneous Surgical debridement and amikacin
M.fortuitum abscess nodules or doxycycline or ciprofloxacin
M. scrofulaceum Cutaneous abscesses Cutaneous abscesses, chronic Treatment- surgical treatment
ulcerative and nodular skin of infected lymph node.
lesions, and cervical Widespread disease- treatment
lymphadenitis same as in M avium complex
Essentials in Dermatology134
14 Connective Tissue Disorders
The term “connective tissue disorders” (Collagen
vascular disorders) encompasses a group of
multi-system disorders which have certain
features in common—the existence of
autoimmunity in the form of antibody production
or disordered cell mediated immunity, vascular
abnormalities in the form of Raynaud’s
phenomenon, occlusive vascular diseases or
vasculitis, arthritis, arthralgia and skin disease.
Involvement of skin is significantly predominant
in this group of disorders. They are: systemic
lupus erythematosus, systemic sclerosis,
dermatomyositis, overlap-syndrome and mixed
connective tissue disease.
Lupus erythematosus (LE) is a multisystem
disease of unknown origin characterized by the
production of numerous diverse types of
autoantibodies. Lupus erythematosus have wide
spectrum of manifestations ranging from solitary
chronic skin lesions in chronic discoid lupus
erythematosus (DLE) to wide spread
polymorphous lesions in subacute lupus
erythematosus (SCLE) to multiple organ
involvement in systemic lupus erythematosus
DISCOID LUPUS ERYTHEMATOSUS
• Most common form of cutaneous lupus
• Characterized by discrete, discoid, well-
defined erythematous plaques covered with
adherent scales (Figs 14.1 and 14.2). The
lesions slowly expand with active
inflammation at the periphery, leaving
depressed scars, telangiectasias and
permanent depigmentation (Fig. 14.3).
• The central scarring with atrophy is very
• These lesions occur most often on the face,
scalp, ears or neck.
• Peeling the scale reveals an undersurface that
tacks called “carpet tack sign”.
• Scarring alopecia occurs in 60% of the cases
• Localized DLE: lesions occur only on the head
• Generalized DLE: lesions are seen both above
and below the neck (Figs 14.5 and 14.6).
Connective Tissue Disorders 135
• The risk is higher in patients with
disseminated DLE (22%).
• Based on clinical features and histopathology.
Direct immunofluorescence (DIF)-deposits of
IgG and C3 along the basement membrane in
affected skin in up to 80%, but normal non-
sun exposed skin always negative. Negative
• Other types are hypertrophic, tumid, lupus
erythematosus profundus, mucosal DLE,
chilblain lupus, etc.
• DLE has a chronic progressive course.
Patients with hematological and serological
abnormalities have 6.5% risk of developing
Fig. 14.1: Discoid lupus erythematosus—well
defined, discoid, erythematous plaques over the
Fig. 14.2: Discoid lupus erythematosus—discoid
lesions involving the face
Fig. 14.3: Discoid lupus erythematosus—discoid
lesions evolving with central depigmentation and
Fig. 14.4: Discoid lupus erythematosus—scarring
Essentials in Dermatology136
or low titer ANA; sometimes higher titer in
disseminated type. Exclude SLE.
Lupus vulgaris (rarely symmetrical, has
progression on one side and healing with
scarring on the other side, apple-jelly nodules on
diascopy), sarcoidosis (lesions are yellowish
have a characteristic translucence and wood-
grains appearance, telangiectasia may be seen on
the surface of the lesions, no prominent follicles),
(brown color, no scarring), psoriasis (silvery
scales), rosacea (pustules, ears spared) and
Jessner’s lymphocytic infiltrate. In each case,
histology is most helpful.
The hypertrophic type of DLE may be
confused with hypertrophic lichen planus,
prurigo nodularis. LE profundus should be
differentiated from other types of panniculitis.
Mucosal DLE should be differentiated from
mucosal lichen planus.
Characteristic histopathological changes are:
• Hyperkeratosis with follicular plugging
• Irregular atrophy of the stratum malphighi
• Liquefactive degeneration of the basal cell
• Patchy perivascular and periappendageal
• Degenerative changes in the connective
tissues—hyalinization, edema, fibrinoid
change in the upper dermis.
• Valuable clues are thickened periodic acid-
deposition of mucin.
• Photoprotection and topical sunscreens
• Topical high potency or intralesional steroids
• Topical calicineurin inhibitors (pimecrolimus,
• Systemic therapy for widespread recalcitrant
disease are antimalarials (Hydroxychloro-
quine 200-400 mg daily or chloroquine
250 mg daily, monitoring by an ophthalmo-
logist required every 6-12 months), dapsone
(50-100 mg daily), thalidomide (50-200 mg
daily), corticosteroids (prednisolone 40 mg
Fig. 14.5: Generalized discoid lupus
erythematosus—discoid lesions involving the trunk
Fig. 14.6: Generalized discoid lupus
erythematosus—discoid lesions involving the feet
Connective Tissue Disorders 137
daily short courses), oral auranofin, etretinate,
isotretinoin, clofazimine, methotrexate,
azathioprine, cyclophosphamide, etc.
SUBACUTE LUPUS ERYTHEMATOSUS
• Characterized by scaly papules on the
shoulders, extensor surfaces of the upper
extremities, upper chest, upper back and neck
in widespread and symmetric fashion.
• Above lesions evolve into two morphological
types either into papulosquamous or annular
and polycyclic lesions. Rarely erythema
multiforme-like with blisters (Rowell
• All patients with SCLE have mild systemic
complaints and 50% of the patients fulfill the
criteria for the diagnosis of SLE.
• SCLE patients have antibodies to the cellular
antigens Ro/SS-A and La/SS-B.
• Children born to mother with SCLE may have
congenital heart block (especially, those with
anti Ro/SS-A antibody).
• Differential diagnosis: To be differentiated
from discoid lupus erythematosus, psoriasis,
tinea corporis, annular erythemas, tinea
versicolor and rarely erythema multiforme.
Same as for discoid lupus erythematosus.
SYSTEMIC LUPUS ERYTHEMATOSUS
SLE a multisystem disorder, primarily affects
skin, joints and vascular system. The age of onset
frequently in females (F: M:: 8:1).
• Exact cause is unknown but there is evidence
to suggest the role of genetic, immune and
various environmental factors.
• It has been postulated that four or more genes
are involved in predisposing an individual to
LE is a multifactorial disease with genetic and
immunopathologic abnormalities. The release of
nuclear antigens because of enhanced apoptosis
is a key factor.
Important predisposing factors are genetic
predisposition (HLA-B8, DR2, DR3, DQwl,
DRB1), complement defects, exogenous factors
(UV radiation, and medications), and individual
factors (hormone status, altered immune status).
The 1982 Revised Criteria for
Diagnosis of SLE are:
1. Malar rash: Fixed erythema, flat or raised,
over the malar eminences, tending to spare
the nasolabial folds (Fig. 14.7).
2. Discoid rash: Erythematous raised patches
with adherent keratotic scaling and follicular
plugging; atrophic scarring may occur in
Fig. 14.7: Systemic lupus erythematosus—malar
and photosensitive rash over the face
Essentials in Dermatology138
3. Photosensitivity: Skin rash as a result of
unusual reaction to sunlight, by patient
history or physician observation.
4. Oral ulcers: Oral or nasopharyngeal
ulceration, usually painless, observed by a
5. Arthritis: Nonerosive arthritis involving two
or more peripheral joints, characterized by
tenderness, swelling, or effusion. or
a. Pleuritis—convincing history of pleuritic
pain or rub heard by a physician or
evidence of pleural effusion.
or evidence of pericardial effusion.
7. Renal disorder:
a. Persistent proteinuria > 0.5 g/day or
greater than 3+ if quantitation not
b. Cellular casts—may be red cell,
hemoglobin, granular, tubular, or mixed.
8. Neurologic disorder:
a. Seizures—in the absence of offending
e.g. uremia, ketoacidosis, or electrolyte
b. Psychosis—in the absence of offending
e.g. uremia, ketoacidosis, or electrolyte
9. Hematologic disorder:
a. Hemolytic anemia—with reticulocytosis
b. Leukopenia < 4000/mL on two or more
d. Thrombocytopenia—<100,000/mL in
the absence of offending drugs.
10. Immunologic disorder:
a. Anti-DNA—antibody to native DNA in
abnormal titer or
b. Anti-Sm—presence of antibody to Sm
nuclear antigen or
c. Positive finding of antiphospholipid
antibodies based on (1) an abnormal
serum level of IgG or IgM anticardiolipin
antibodies, (2) a positive test result for
lupus anticoagulant using a standard
method, or (3) a false-positive serologic
test for syphilis known to be positive for
at least 6 months and confirmed by
Treponema pallidum immobilization or
fluorescent treponemal antibody
11. Antinuclear antibody (ANA): An abnormal
titer of antinuclear antibody by immuno-
fluorescence or an equivalent assay at any
point in time and in the absence of drugs
known to be associated with “drug-induced
Note: The proposed classification is based on 11
criteria. For the purpose of identifying patients in
clinical studies, a person shall be said to have
SLE if any 4 or more of the 11 criteria are present,
serially or simultaneously, during any interval of
Chief Cutaneous Features
• Butterfly rash.
• Raynaud’s phenomenon.
• Non-scarring alopecia-short hairs in the
frontal region are referred to as lupus hairs.
• Urticarial vasculitis.
• Mouth ulceration.
• Bullous lesions.
• Chronic discoid LE lesion.
• Cutaneous vasculitis.
• Other features are vasculopathy, periungual
telangiectasia, leg ulcers, erythema multi-
• Complete blood count, ESR.
• Urine analysis for microscopic hematuria and
Connective Tissue Disorders 139
• Skin biopsy- There is no single diagnostic
pathological feature in the skin, but a
combination of features aids diagnosis. Some
changes are similar to DLE. The primary
pathological lesions of SLE are fibrinoid
necrosis, collagen sclerosis, necrosis and
basophilic body formation and vascular
containing engulfed nuclear material) or
rosette phenomenon (neutrophils surroun-
ding nuclear debris, trying to engulf it).
• Lupus band test- deposits of IgG and C3 along
the basement membrane on normal, non-sun
exposed skin suggest SLE but is no longer an
accepted criterion. It positively correlates with
the presence of anti-ds DNA antibodies and
with risk for developing LE nephritis.
• C3, C4, CH50 levels.
• Serum globulins are frequently raised
especially gamma globulin.
• ANA (Commonest pattern is homogeneous;
peripheral pattern-predictor of renal
• Antibodies-SSA (Ro), SSB (La), Sm, nRNP.
erythema multiforme, polyarteritis nodosa, acute
rheumatic fever, rheumatoid arthritis, pellagra,
pemphigus erythematosus, drug eruption,
hyperglobulinemic purpura, Sjogren’s syndrome,
necrotizing angiitis and myasthenia gravis. In
SLE, there may be fever, arthralgia, weakness,
lassitude, diagnostic skin lesions, an increased
ESR, cytopenias, proteinuria, immunoglobulin
deposition at dermoepidermal junction and a
positive ANA test. Biopsies of skin lesions and
involved kidney may also be diagnostic.
SLE with only cutaneous lesions and arthritis:
• NSAID’s, antimalarials, prednisolone ( 1-2 mg
per kg body weight daily).
• Dapsone most effective in urticarial vasculitis
and bullous SLE.
Severe Disease with
• Steroid pulse therapy.
• Immunosuppressants such as azathioprine
(100-150 mg daily), cyclophosphamide (50-
100 mg daily), methotrexate (7.5-20 mg
(2 gm daily) and cyclosporine (5 mg/kg body
• Intravenous immunoglobulins, plasma-
pheresis, anti CD20 (rituximab), -CD40 and –
TNF alpha antibodies.
Course and Prognosis
The course of the SLE is very variable. Acute
fulminating cases are much less common than
subacute cases, which smoulder on for many
is a connective tissue disorder characterized by
generalized or localized sclerosis of the skin. The
localized type is called morphea.
Morphea – Localized (Circumscribed plaque,
morphea profundus, bullous, linear, en coup de
sabre) and generalized.
Essentials in Dermatology140
Systemic sclerosis – LM (Limited cutaneous) SSc,
DC (Diffuse cutaneous) SSc.
Occupational scleroderma – Polyvinylchloride,
perchlorethylene, trichloroethylene, organic
solvents, malathion, DDT, epoxy resins, silicosis.
Iatrogenic scleroderma – Bleomycin, carbidopa,
pentazocine, cocaine, appetite suppressants,
silicone or paraffin implants, GVHD.
Pseudoscleroderma – Scleroedema of Buschke,
Scleromyxoedema, prophyria cutanea tarda,
Primary systemic amyloidosis, carcinoid
Miscellaneous – Toxic oil syndrome, eosinophilic
• Most common form of morphea.
• Occurs most commonly in females than males
and primarily in young adults.
• Seen commonly on the trunk.
• The lesion of morphea may begin as
erythematous macule, evolve into ivory-
colored center and violaceous bordered
• Lesions slowly involute over 3 to 5 years
period leaving permanent atrophic skin or
normal appearing skin behind.
• Lesions are more numerous and larger
• Often coalesce to involve extensive portions
of the body.
• Muscle atrophy may be associated.
Pansclerotic Morphea (Morphea
• Sclerosis involves dermis, panniculus, fascia,
muscle and bones.
• There is disabling limitation of the joints.
En Coup De Sabre
• It is a variant of linear scleroderma involving
scalp parasagitally on frontal scalp and
forehead (Figs 14.8 and 14.9).
• Often has the configuration of the stroke of a
saber (en coup de sabre).
1. Morphea-like lesions can occur in sarcoidosis
and morpheic basal cell carcinoma.
Figs 14.8 and 14.9: En coup de sabre—linear indurated depressed lesion in the midline over the forehead
Fig. 14.8 Fig. 14.9
Connective Tissue Disorders 141
Histopathology is required to differentiate
2. Lichen sclerosus atrophicus (ivory white
plaques with follicular delling and atrophy)
and subcutaneous zygomycosis may
resemble morphea. Fingers can be insinuated
below the plaques of subcutaneous
3. Pseudoscleroderma especially porphyria
cutanea tarda and graft versus host disease.
4. Drug reaction (bleomycin induced sclerosis,
atrophic morphoeic plaques from intra-
muscular injection of vitamin K or
subcutaneous corticosteroid injections).
• Natural history is towards spontaneous
• Topical steroid, intralesional steroids and oral
• Topical calcipotriol.
• Bath PUVA or UVA1.
• For widespread or rapidly advancing disease
sclerosis (corticosteroids, d-penicillamine,
cyclopsporine, low dose methotrexate,
etretinate, phenytoin, plasmapheresis).
• Physiotherapy may be helpful in preventing
It is characterized by cutaneous and internal
organ fibrosis. Raynaud’s phenomenon is the
earliest feature and may precede the onset of
disease by months or years. The heart, lungs,
gastrointestinal, kidney and other organs may be
Exact cause of systemic sclerosis is unknown.
Important steps in its pathogenesis include:
• Excessive synthesis of collagen and matrix
• Endothelial cell injury.
• Dysregulation of the immune system.
• Diffuse disease: Characterized by extensive
proximal and truncal skin induration.
• Limited disease: Induration is confined to
hands, forearm, face, and legs. Its variant is
called CREST syndrome (Thibierge-
Weissenbach syndrome) (Calcinosis,
Raynaud’s phenomenon, Esophageal dys-
function, Sclerodactyly and Telangiectasia).
• Scleroderma proximal to the digits, affecting
limbs, face, neck and trunk.
• Sclerodactyly (Fig. 14.10).
• Digital pitted scarring (Fig. 14.11).
• Bilateral basal pulmonary fibrosis.
One major criterion or two or more minor
Note: These criteria have 97% sensitivity and 98%
Fig. 14.10: Progressive systemic sclerosis—
sclerodactyly with calcification over the inter-
phalangeal joints of fingers
Essentials in Dermatology142
Three phases of dermal involvement can be
1. Edematous phase (stiff, puffy, fingers)
2. Indurative phase (hard, tight, hide bound)
3. Atrophic phase (softened skin, burnt out).
Hands and Feet
• Early: Raynaud’s phenomenon.
• Swollen or tumid fingers and hands.
• “Round finger pad sign”-fingers lose their
normal peaked contour but rather appear as
rounded hemisphere when viewed from the
with pitted scars.
• Late: sclerodactyly (induration of skin over
the fingers) with tapering of fingers (Figs 14.10
• Skin is tightly bound down.
• Leathery crepitations over joints and flexion
• “Heuck-Gottron sign”- loss of cuticle with
• Bony resorption.
• Atrophy of the pulp of the fingers.
• Gangrene of the fingers.
• Periorbital edema is the early manifestation
• Late manifestations include: Mask like facies
(difficulty in eversion of lower eyelids),
thinning of lips, microstomia, radial perioral
furrowing, small sharp nose (Fig. 14.12),
telangiectasia (mat-like) and diffuse
• Forehead is smooth and shiny, and skin is
bound down and hard.
• There is reduced wrinkling on the forehead
and mandibular atrophy.
• Early: tense, stiff and waxy appearing skin
that cannot be pinched and folded.
• Late: impairment of respiratory movement of
chest wall and of joint mobility.
• “Neck sign”-ridging and tightening of the
neck on extension due to sclerosis.
Fig. 14.11: Progressive systemic sclerosis—finger
tip pits due to scarring
Fig. 14.12: Progressive systemic sclerosis—mask
like facies, thinning of lips and small sharp nose
Connective Tissue Disorders 143
“Salt and pepper” pigmentation (Fig. 14.13),
gangrene of fingers, mat like telangiectasia, leg
ulcers and livedo reticularis.
Organ Involvement in PSS
• Esophageal fibrosis, pulmonary interstitial
fibrosis, myocardial fibrosis, small intestinal
fibrosis, large intestinal fibrosis, renal
involvement, skeletal muscle atrophy and
• Others are bone, eye, CNS, teeth, tendons.
• Routine tests such as complete hemogram,
liver function tests, sedimentation rate,
• Skin biopsy- Dermal sclerosis typically results
in rectangular punch biopsy specimen. As the
dermis replaces the subcutaneous tissue,
eccrine glands appear to be in the mid portion
of the thickened dermis. The subcutaneous fat
is quantitatively reduced and adventitial fat
is lost. On DIF testing of skin the nucleolus
may be stained in the keratinocytes if
antinucleolar circulating antibodies are
present and a “pepper dot” epidermal nuclear
pattern may be seen in CREST patients who
• Nail fold capillary microscopy.
• ANA (+ve in more than 90%), Ab-SSA, SSB,
sclerosis), anticentromere antibody (specific
for CREST syndrome).
• Rheumatoid factor positive in 30%
• Organ workup: urine analysis, barium
swallow, esophageal manometry, barium
enema, chest x-ray and pulmonary function
1. Generalized morphea (Raynaud’s
phenomenon is rare, systemic involvement is
unusual, no atrophic stage, no facial
telangiectasia or perioral furrowing, skin of
trunk and limbs are equally involved)
2. Pseudosclerodermas (Specific features of each
should be looked for)
3. Occupational and iatrogenic scleroderma
(History of specific exposure should arouse
4. Other collagen vascular disorders- mixed
collagen vascular disorders, overlap
5. Graft versus host disease
Prognosis and Cause of Death
• Course of the disease is variable. Death occurs
cardiac failure, renal failure, sometimes,
Other Conditions Where Sclerodermoid
Changes are Seen
Phenylketonuria, progeria, Rothmund-Thomson
syndrome, Werner’s syndrome, porphyria
cutanea tarda, primary systemic amyloidosis,
Hashimoto’s disease, carcinoid syndrome,
Fig. 14.13: Progressive systemic sclerosis—“salt and
pepper pigmentation”—depigmentation with
speckled hyperpigmented macules over the front of
Essentials in Dermatology144
childhood diabetes mellitus and drugs
(bleomycin, pentazocine, carbidopa, and
There is no specific treatment and no therapy is
known to alter the course of a disease. Treatment
is primarily directed towards complications.
Pharmacological agents used for systemic
sclerosis can be grouped into various categories.
• Collagen modulators: D-penicillamine (125
mg alternate days, 750-1500 mg per day),
relaxins, and interferons.
• Vasoactive agents: Captopril, nifedipine and
• Immunosuppressive agents: Systemic corti-
costeroids (prednisolone 0.5 mg mg per kg
body weight daily), azathioprine (1-2 mg mg
per kg body weight daily), cyclophosphamide
(2 mg per kg body weight daily), cyclosporine
(3-5 mg per kg body weight daily) and
methotrexate (20-30 mg weekly).
converting enzyme inhibitors are treatment of
choice for renal hypertension, proton pump
inhibitors (omeprazole 20-40 mg daily) indicated
for esophageal dysfunction and for pulmonary
hypertension intravenous prostacyclin; inter-
stitial lung disease may respond best to
cyclophosphamide. Physical therapy can help
avoid contractures and retain function.
It is a systemic, inflammatory disease involving
primarily skin and muscles. Symmetric, proximal
muscle weakness occurs especially in the hips,
thigh, and upper arm. Patients with only
muscular symptoms and signs but no cutaneous
findings are said to have polymyositis. These can
be associated with malignancies especially in
adulthood – carcinoma of lung, breast, female
genital tract, stomach, kidney and testes.
Cutaneous Manifestations of
• Gottron’s papules: Violaceous, flat topped
papules on interphalangeal joints and
knuckles. Similar lesions may occur over other
bony prominences such as knees, elbows and
erythema with or without edema over the
above mentioned sites.
• Periorbital violaceous erythema with
associated edema of eyelids and periorbital
tissue (heliotrope rash) (Fig. 14.14).
• Periungual telangiectasia with associated
• Macular violaceous erythema overlying the
dorsal hands, extensor forearms and arms,
deltoids, posterior shoulders, nape of neck, V
area of neck, upper chest and forehead.
“Shawl sign”-erythema and scale (with or
without poikiloderma) over the shoulder
• Mechanic’s hands: Bilaterally symmetrical
Fig. 14.14: Dermatomyositis—“Heliotrope rash”—
periorbital violaceous erythema with associated
edema of eyelids
Connective Tissue Disorders 145
ulnar aspects of the thumbs and radial aspects
of the index and middle fingers with
occasional extension to the palmar surface.
• Poikiloderma atrophicans vasculare
• Calcinosis cutis.
Systemic features include arthritis (25%), oral
ulcers (20%), calcinosis (distinctive feature of
juvenile dermatomyositis), pulmonary fibrosis
(20%), gastrointestinal ulcerations and
hemorrhages, occasionally myocarditis or
• Skin biopsy, muscle biopsy, muscle enzymes,
electromyography, ANA, Ab-SSA, SSB, Sm,
nRNP, Jo-1and PM-1.
1. Progressive symmetric proximal muscle
2. Elevated muscle enzyme levels.
3. Abnormal electromyogram.
4. Abnormal muscle biopsy.
5. Characteristic cutaneous manifestations.
Definite: 5 plus three other criteria.
Probable: 5 plus two other criteria.
Includes other myopathies (inclusion body
myositis, muscular dystrophy, neuromuscular
Cushing’s disease, sarcoidosis, alcoholism),
drugs (lipid lowering agents, hydroxyurea,
NSAIDs), overlap syndromes, vasculitis,
polymyalgia rheumatica and trichinosis.
• Skin disease: Topical steroids, hydroxy-
• Muscle disease: Systemic corticosteroids are
first line therapy. Second line agents are
methotrexate (5-15 mg weekly) and
azathioprine (1-3 mg per kg body weight
• Intravenous immunoglobulins are indicated
for resistant cases, children with vasculitic
component and those with steroid induced
• Bed rest during flares, physical therapy when
• Appropriate treatment of underlying
malignancy where it is associated.
• The term overlap syndrome may be used
when patients exhibit symptoms of more than
one connective tissue disease.
• Such patients may meet diagnostic criteria for
one disease but also have atypical
manifestations or findings suggestive of
• Systemic sclerosis combined with dermato-
myositis is the most frequently seen overlap
MIXED CONNECTIVE TISSUE DISEASE
• This entity was first described by Sharp and
colleagues in 1972.
• These patients, predominantly female, show
features of SLE, systemic sclerosis, dermato-
myositis and polymyositis.
• All patients have high titer of antibody to U1
• Prominent clinical features include myositis,
pulmonary hypertension, Raynaud’s pheno-
menon, oesophageal hypomotility, swollen
hands and sclerodactyly.
SJÖGREN’S SYNDROME (SS)
• Sjögren in 1933 described a triad of
keratoconjunctivitis sicca, xerostomia and
Essentials in Dermatology146
• Dry eyes and dry mouth occur in primary
Sjögren’s syndrome or if associated with other
connective tissue disease then referred to as
secondary Sjögren’s syndrome.
• Most patients are aged 50 years or older and
• Clinical features include xerostomia, rhinitis
sicca, vaginal dryness and dry eyes (Fig.
• Skin manifestations of SS include vasculitis,
xerosis and annular erythema.
• Rheumatoid factor is usually positive.
• 80% of patients have anti Ro/SSA antibodies.
• Increased risk of developing lymphoreticular
• No specific treatments available, only
LICHEN SCLEROSUS ET ATROPHICUS
• It is a chronic disease of the skin and mucous
membrane of unknown origin predominantly
affecting the females.
• Early lesions of LSA are ivory white,
polygonal, flat-topped papules or plaques
coalesce into large atrophic plaques.
• In women, involvement of the vulvar and
perianal areas leads to the typical “figure of
Fig. 14.15: Sjögren’s syndrome—face showing
submandibular salivary gland enlargement
eight” or “ hour glass” appearance (Fig. 14.16)
• LSA of the penis in adults (Balanitis xerotica
obliterans) presents with acquired phimosis
or recurrent balanitis (Fig. 14.17).
• LSA of vulva (Kraurosis vulvae) usually seen
in postmenopausal women.
• LSA of the genitalia have increased risk for
squamous cell carcinoma (Fig. 14.18).
Fig. 14.16: Lichen sclerosus et atrophicus of the vulva-
typical “figure of eight” or “hour glass” appearance
Fig. 14.17: Lichen sclerosus et atrophicus—ivory
white induratedringlikelesioninvolvin preputial orifice
Connective Tissue Disorders 147
On trunk- morphea, annular atrophic plaque type
of DLE and vitiligo, female genitalia-vitiligo,
chronic dermatitis, erosive lichen planus,
autoimmune bullous diseases, male genitalia-
balanitis in all its variants, idiopathic phimosis,
erosive lichen planus.
Fig. 14.18: Lichen sclerosus et atrophicus—male penis with
squamous cell carcinoma
Medical—Topical steroids or intralesional
steroids, topical pimecrolimus or tacrolimus,
topical testosterone, topical tretinoin, UVB and
bath PUVA therapy. Surgical correction of
adhesions may be required.
Essentials in Dermatology148
Human race has a wide variation in normal skin
color (pale white, light brown, dark brown and
black). Various skin chromophores like brown
(melanin), red (oxyhemoglobin), blue (deoxy-
hemoglobin) and yellow-orange (carotene) are
responsible for skin color. Of course, melanin is
the major component of skin color. Skin color
depends on the genetic make-up of an individual
and environmental effects like ultraviolet
radiation exposure. Melanocyte is the sole site of
Pigmentary disturbances include decrease or
absence or increase in pigmentation which could
be either epidermal or dermal. These pigmentary
changes are a result of changes in number of
melanocytes or amount of melanin.
Pigmentary disorders may be congenital or
acquired, circumscribed or generalized,
hypomelanotic (Vitiligo, albinism, piebaldism,
Waardenburg’s syndrome) or hypermelanotic
(Melasma, freckles, lentigo, Peutz Jeghers
Vitiligo is defined as a common, dermatological
disorder characterized by well-circumscribed,
milky-white cutaneous macules devoid of
15 Pigmentary Disorders
identifiable melanocytes. In India, the incidence
of vitiligo is estimated to be between 3 and 4 %.
The term vitiligo is probably derived from the
Latin word “vitium”(“blemish”). Many ancient
terms are applied to this condition—
shwetakustha in the sacred Indian book, Atharva
Veda (1400BC), and switra in Manusmriti (200
BC). In South India where the old Dravidian
language of Tamil is spoken, the condition is
known as ven kushtam—”white leprosy.”
The white macules of vitiligo are the result of a
loss of melanocytes. The mechanism(s) by which
the melanocytes are lost may be multiple but have
not been identified unequivocally. Seven hypo-
theses, not mutually exclusive, have been
proposed to explain the causation of vitiligo:
• Autoimmune: Strengthened by the
demonstration of specific autoantibodies to
melanocyte cell surface antigens and the
association of vitiligo with a variety of
• Autocytotoxic: Also called the self-destruction
theory, it proposes melanocyte destruction by
intracellular retention of various precursors
of melanin synthesis.
• Neural: Especially proposed to explain the
segmental type of vitiligo.
Pigmentary Disorders 149
• Biochemical: Accumulation of pteridines (6-
biopterin and 7-biopterin) in the vitiliginous
skin causes the depigmentation.
• Antioxidant deficiency theory: There is an
increased level of norepinephrine and
catecholamine derivatives in vitiligo skin
which leads to tissue ischemia and increased
in turn causes excess production of stress
related hydrogen peroxide. Reduced catalase
activity in vitiligo skin leads to impaired
degradation of H2O2 and accumulation of
superoxide radicals causing depigmentation.
• Melanocyte growth factor reduction hypothesis:
factors derived from keratinocytes, fibroblasts
and other tissues.
• Intrinsic (genetic) theory: An underlying
genetic/intrinsic factor predisposes some
individuals to be more prone to develop
• The diagnostic lesion of vitiligo is the typical
vitiligo macule, which is of variable size,
round/oval in shape, has a milky white color
and scalloped margins (Fig. 15.1).
• May appear at any age, however, the peak age
at onset has been reported to be five to thirty
• Prevalence is the same in both sexes.
• The natural course of the disease is of gradual
progression, the lesions increasing both in
number and size. In some cases there may be
a rapid downhill course of vitiligo and this
has been termed ‘galloping vitiligo’ or ‘vitiligo
• Segmental vitiligo and vitiligo in children
have a better prognosis.
• Mucous membrane involvement is also noted
in vitiligo and is commoner, or rather, easily
detectable in dark-skinned races.
• Leukotrichia refers to depigmentation of the
hair and may occur in some patients.
Classification of Vitiligo
• Focal vitiligo: This consists of one or more
macules in one area but not clearly in a
segmental or zosteriform distribution .
• Segmental vitiligo: Number of macules
involving a unilateral segment of the body.
The lesions stop abruptly at the midline of the
affected segment (Fig. 15.1).
• Mucosal vitiligo: Vitiligo affecting mucous
membranes of the lips, oral cavity or the
genitalia (Fig. 15.2).
Fig. 15.1: Zosteriform vitiligo—milky white macules
in a zosteriform distribution over the back.
Fig. 15.2: Vulval vitiligo—female genitalia involved
by milky white lesions
Essentials in Dermatology150
• Acrofacial vitiligo: Lesions on the acral areas
(hands and feet) (Fig. 15.3) and on the face,
very often the perioral areas.
• Vitiligo vulgaris: Multiple macules of variable
to bilateral symmetry (Fig. 15.4).
• Lip-tip vitiligo: Lesions affecting the tips of the
digits and the lips (Fig. 15.5)
• Mixed: Any combination- of vitiligo vulgaris
and acrofacial vitiligo or of vitiligo vulgaris
with segmental vitiligo.
• Universal Vitiligo: This is the term used to
describe complete or near complete depig-
Special Signs in Vitiligo
• Trichrome vitiligo: The trichrome sign, also
termed ‘vitiligo gradata’ describes a tan
normal skin and the depigmented macules
(Fig. 15.2). ‘Quadrichrome vitiligo’ implies the
presence of a fourth color – dark brown – at
the sites of perifollicular repigmentation.
• Pentachrome vitiligo: Has five colors—white,
pigmented, and normal skin color.
• Inflammatory vitiligo: Here skin lesions of
should be differentiated from the erythema of
• Koebner’s sign: This phenomenon, a common
feature of vitiligo, is defined as the
development of lesions along the lines of
specific trauma such as a cut, burn or abrasion.
It may be a marker of disease activity.
Fig. 15.3: Acral vitiligo—vitiligo involving
hands and feet
Fig. 15.4: Vitiligo vulgaris—multiple depigmented and
hypopigmented macules over the chest and
abdomen (Trichrome vitiligo)
Fig. 15.5: Lip tip vitiligo-lesions affecting the tips of
the digits and the lips
Pigmentary Disorders 151
Association of Vitiligo with Other
Vitiligo has been shown to be associated with
autoimmune thyroid disease, Addison’s disease,
pernicious anemia, diabetes mellitus and various
dermatological disorders like alopecia areata,
scleroderma, psoriasis and collagen vascular
disorders. The Vogt Koyanagi Harada syndrome
is an apparently rare, multisystem disease
characterized by vitiligo, poliosis, uveitis,
dysacousia, and alopecia.
Differential Diagnosis of
Localized Vitiligo Includes
Naevus depigmentosus (localized hypo-
melanosis present since birth), naevus anemicus
(pale area due to vasoconsconstriction), leprosy
(suspect in an endemic area, shows hypo-
anesthetic or anesthetic hypopigmented patch/
es), pityriasis alba (hypopigmented macular
lesions have ill defined margins with fine scaling,
self limiting course), postinflammatory hypo-
melanosis (such cases have preceding history of
dermatoses, and the skin lesions are ill defined),
tinea versicolor (typical localization to upper
trunk, pigmented macular lesions have fine
powdery scales, KOH +vity conclusive), ash-leaf
macules and confetti depigmentation of tuberous
sclerosis, and idiopathic guttate hypomelanosis
(tiny porcelain white macules, 2-6 mm with
distinct margins, localized to limbs in older
Differential Diagnosis of
Generalized Vitiligo Includes
to the site of contact), leprosy (suspect in an
endemic area, has anesthetic hypopigmented
patch/es), mycosis fungoides (unpatterned
lesions, diagnosis confirmed by biopsy),
postinflammatory hypomelanosis (hypopig-
mented macules with ill defined border, history
of preceding dermatoses like psoriasis, eczema,
pityriasis rosea, etc. in same areas with pattern
mimicking it), tinea versicolor (has fine powdery
scales over the lesions, in doubt do KOH
examination of skin scrapings), Waardenburg’s
syndrome, albinism and piebaldism (see next
page for last three).
Treatment of vitiligo can be broadly divided into
medical and surgical modalities.
1. Photoprotection: It prevents sunburn and
Koebner phenomenon, prevents tanning of
uninvolved skin and therefore lessens
contrast between normal and depigmented
2. Topical potent corticosteroids.
3. Intralesional corticosteroids: (Triamcinolone
acetonide) especially for leukotrichia on
4. Human placental extract.
5. Topical immunomodulators: Such as
tacrolimus (0.1%, 0.03%), pimecrolimus or
tacrolimus (0.1%) combined with narrow
band UVB three times a week.
6. Calcipotriol: Can be used as monotherapy or
combined therapy (sunlight, PUVA, or
narrow band UVB, clobetasol).
7. Topical pseudocatalase + calcium + UVB
: Formulation containing superoxide
dismutase and catalase. It removes
hydrogen peroxide from skin, thereby helps
9. Phenytoin local application: It inhibits release
oxidase, inhibits the production of
superoxide anion and suppresses cytotoxic
T- lymphocyte activity and induces type 2
like cytokine profile.
Essentials in Dermatology152
10. Dead sea climatotherapy in combination with
pseudocatalase: Here patients take bath in
dead sea for 15 minutes twice daily followed
by a shower to wash off salt followed by
application of pseudocatalase cream prior
to sun exposure.
11. Topical prostaglandin analogues (PGE2).
12. Cosmetic camouflage where nothing works
or when on treatment.
1. Low dose oral corticosteroids-prednisolone
0.3 mg/kg body weight daily.
2. Oral dexamethasone or betamethasone pulse
therapy- 0.5 mg/ every 5 kg body weight for
two consecutive days in a week.
8 mg/kg/day IV over 30 minutes for three
consecutive days every 4-8 weeks.
4. Multivitamin therapy (folic acid/vitamin B12/
5. Antioxidants (β-carotene, α-tocopherol,
methionine, ubiquinone, vitamin C).
6. Immunomodulators- Levamisole 150 mg on
two consecutive days every week; cyclo-
phosphamide 50 mg twice daily; cyclosporine
6 mg/kg/day; dapsone 100 mg/day; azathi-
7. Quinoline compounds- chloroquine 250 mg/
day and hydroxychloroquine 400 mg/day.
They can be combined with psoralen therapy.
• Psoralen (stimulates melanogenesis in
presence of ultra violet radiation)with
ultraviolet A therapy (PUVA)- topical and
• Khellin + UVA (KUVA). Khellin is extracted
from seeds of the plant Ammi visnaga. It can
be given either topically or systemically.
Khellin is given orally 50-100 mg/day, 2.5
hours prior to sun or UVA exposure up to 15
. But due to systemic toxicity, topical
preparation of khellin is recommended.
• Phenylalanine + UVA (PAUVA). Pheny-
alanine both topically and systemically can
be used in combination with UVA. Pheny-
alanine can be used at a dose of 50-100 mg/
kg body weight 45 minutes prior to UVA
• UVB radiation especially narrow band UVB
• Targeted light therapy and Excimer laser (308
• Stable vitiligo (i.e. no new lesions for last two
• Refractory to medical management.
• Punch grafting
• Split skin thickness graft
• Blister grafting
• Melanocyte culture and transplantation
• Therapeutic spot and regional dermabrasion
• Trypsinized autograft injection
• Topical 5- fluorouracil combined with
For universal vitiligo options for depigmentation
• Depigmentation with 20% monobenzyl ether
of hydroquinone (for islands of residual
repigmentation in extensive vitiligo).
• Imatinib mesilate 400 mg/day for 15 days,
then 300 mg once a day for 30 days has caused
vitiligo-like depigmentation. It is a selective
inhibitor of several tyrosine kinases.
• Autosomal recessive inherited disorder.
• It is characterized by reduced melanin
synthesis in the melanocytes of the skin, hair,
and eyes, termed oculocutaneous albinism
Pigmentary Disorders 153
(OCA), and hypopigmentation primarily
involving the retinal pigment epithelium of
the eyes termed ocular albinism (OA).
• Due to genetic abnormalities of melanin
synthesis associated with normal number
and structure of melanocytes (differentiate it
from vitiligo where melanocytes are reduced
• Tyrosinase-related OCA, the most common
type of albinism is produced by loss of
resulting from mutations of the tyrosinase
• Affected individuals are born with white or
blond hair and skin and blue eyes (Fig. 15.6).
• Piebaldism is an uncommon, autosomal
dominant, congenital, stable leukoderma
like amelanotic macules, usually containing
a few normally pigmented or hyper-
pigmented macules (Fig. 15.7).
• Hyperpigmented macules within the
amelanotic macules and on normally
pigmented skin are characteristic of
WS (Waardenburg syndrome–Hirschsprung’s
disease or Shab-Waardenburg syndrome) is a rare
autosomal dominant disorder that is
• Lateral displacement of the inner canthi and
of lacrimal puncta
• Prominence of the nasal root and of the medial
• Congenital deafness
• Heterochromic irides
• White forelock
• Hypomelanotic macules.
• Melasma is a common acquired hyper-
melanosis that occurs exclusively in sun-
exposed areas; it is exacerbated by sun
exposure, pregnancy, oral contraceptives, and
certain anti-epilepsy drugs.
• Melasma presents in one of three usually
symmetric facial patterns. The most common
Fig. 15.6: Albinism—Blond hair and white skin with
Fig. 15.7: Piebaldism—typical white forelock
Essentials in Dermatology154
is a centrofacial pattern involving the cheeks
(Fig. 15.8), forehead, upper lip, nose, and chin.
Less common are the malar pattern, involving
the cheeks and nose, and the mandibular
• Successful treatment of melasma involves the
triad of sunblocks, bleach and time.
It is an area of pale brown pigmentation usually
less than 3 mm with poorly defined lateral
• Freckle appears as result of functionally
overactive melanocytes (though they are
normal in number )
• They are seen only in fair skinned people
• They are stimulated by ultra violet radiation
and fade away during winter
• Histology reveals excess of melanin pigment
in the basal layer.
LENTIGO (PLURAL: LENTIGINES)
It is a sharply demarcated brown pigmented
macule usually circular or polycyclic in shape.
• Lentigo appears as a result of increased
number of melanocytes in the basal layer
• They do not show seasonal colour variations
( not affected by ultra violet radiation).
• Histology reveals linear increase of
melanocytes in the basal layer
Syndromes Associated with Lentigines
• LEOPARD syndrome:
Ocular abnormalities (hypertelorism),
Abnormalities of genitalia,
Retardation of growth and
• NAME syndrome:
Myxoid neurofibromas and
• LAMB syndrome:
Mucocutaneous myxomas and
PEUTZ JEGHERS SYNDROME
• Peutz-Jeghers syndrome is an autosomal
dominant disorder characterized by pig-
mented macules (lentigines) of the buccal
mucosa, lips, fingers, and toes and by
• It is caused by mutations in a novel serine
threonine kinase, and its gene has recently
been mapped to chromosome 19p.
• The pigmented macules (dark brown or blue-
brown) are most common on the buccal
mucosa and lips, but also seen over palate and
tongue. The macules on the skin are usually
dorsa of the hands and feet and perium-
• The diagnosis is particularly important
because of the presence of gastrointestinal
polyps, which are most frequent in the small
bowel, particularly the jejunum, which may
manifest with gastrointestinal bleeding.
Malignant change may occur in these polyps.
Fig. 15.8: Melasma—hyperpigmented light brown
macules over the cheeks
Pigmentary Disorders 155
• Any child with recurrent, unexplained
abdominal pain should be examined for the
typical mucosal, and periorificial pigmented
lesions of Peutz-Jeghers syndrome.
DRUGS CAUSING HYPERPIGMENTATION
• Generalized–Addisonian-like occurs with
ACTH and generalized diffuse due to clofa-
zimine, cyclophosphamide, minocycline, etc.
– Melasma- like- estrogen, progesterone,
– Knuckle pigmentation- bleomycin
– Palmoplantar- cyclophosphamide, doxo-
– Linear – bleomycin (flagellate), zido-
Essentials in Dermatology156
Ichthyosis (from Greek ichthys “fish”) denotes a
group of hereditary and acquired disorders of
keratinization characterized by the development
of dry rectangular scales.
Hereditary (Inherited) Ichthyoses
It is a common autosomal dominant disorder
characterized by mild scaling on extensor aspect
of the limbs (Fig. 16.1), more than trunk and
spares the flexures. Increased palmar markings
or frank palmoplantar keratoderma may be
associated features. Onset is after 3 months of age.
Scaling gets worse in winter.
Differential diagnosis: Atopic xerosis, eczema
craquele, acquired ichthyosis, and Refsum’s
X-linked Recessive Ichthyosis
It appears in infancy and occurs in males. Females
may be heterozygotes and female carriers are
dirty brown scales characterize it. Extensor and
flexor aspects of the limbs are involved but spare
rhomboidal spaces in body folds (Figs. 16.2 and
16.3). Palms and soles are spared but the neck,
16 Keratinization Disorders
side of the face and trunk are affected. This form
of ichthyosis is associated with steroid
Differential diagnosis: In contrast to ichthyosis
vulgaris, no hyperlinear palms, no keratosis
pilaris, flexural involvement and larger, darker
Fig. 16.1: Ichthyosis vulgaris—scaling limited to
extensor aspects of limbs (shin)
Keratinization Disorders 157
Lamellar ichthyosis is a rare form of ichthyosis,
which presents at birth as “Collodion baby”; baby
is encased in a taut inelastic membrane. In this
autosomal recessive disorder, the baby later
develops large, thick plate like scales all over
the body including flexures. Facial involvement
often results in ectropion and eclabium (Figs 16.4,
Differential diagnosis: Includes X-linked
recessive ichthyosis and ichthyosiform
eythrodermas with collodion presentation.
Figs 16.2 and 16.3: X-linked recessive ichthyosis—large dirty brown scaling involving flexor and extensor
aspects of limbs and trunk but sparing rhomboidal spaces in body folds
Fig. 16.4: Lamellar ichthyosis—face involvement by
erythema and scaling
Fig. 16.5: Lamellar ichthyosis—brownish plate like
scales over the trunk
Fig. 16.2 Fig. 16.3
Essentials in Dermatology158
Fig. 16.6: Lamellar ichthyosis—large plate like
scales involving lower legs
Figs 16.7 and 16.8: Bullous congenital ichthyosiform
erythroderma—no more blisters seen, body folds
show thick dark gray brown scales forming warty,
Fig. 16.9: Bullous congenital ichthyosiform
erythroderma—palms involved by keratoderma
Congenital Ichthyosiform Erythroderma
It is of two types:
1. Bullous congenital ichthyosiform erythro-
derma: It is inherited as an autosomal
dominant trait. At birth, the skin is
erythematous, moist and tender. Blisters
dark gray brown scales form warty-ridged
pattern (Figs 16.7 and 16.8). There is
accentuation in the areas of flexures and on
the palms and soles (Fig. 16.9). Normal
appearing skin within a hyperkeratotic area
is a valuable diagnostic sign. Skin colonization
by Staphylococcus brevibacterium and
possibly fungi produces a distinctive and
embarrassing body odor. Ectropion and
deformed ears are common.
Differential diagnosis: At birth, may be
confused with epidermolysis bullosa,
staphylococcal scalded skin syndrome,
herpetic infections and incontinentia
pigmenti. In older patients, ichthyosis hystrix,
ichthyosis bullosa of Siemens, and non-
epidermolytic epidermal naevi may resemble
bullous congenital ichthyosiform
2. Nonbullous congenital ichthyosiform
erythroderma: It is an autosomal recessive
disorder. Most infants with it are born as
Keratinization Disorders 159
collodion baby. As the membrane is cast off in
10 to 14 days, generalized erythema and
scaling are apparent. Scales may be large and
plate like on the legs but are apt to be fine on
the trunk, face and scalp. It has a tendency to
improve at the time of puberty. Ectropion,
deformities of the ears and sparsity of the
scalp hair are common accompaniments.
Differential diagnosis: Congenital infections
such as candidiasis, congenital psoriasis,
Netherton’s syndrome, immunodeficiency
disorders, trichothiodystrophy and neutral
signs of non-bullous ichthyosiform
• A collodion baby is the usual presentation of
congenital recessive ichthyosis. Kollodes is the
Greek word for glutinous or glue like. The child is
born encased in a transparent, parchment-like
membrane, which is taut and may impair
respiration and sucking. Collodion presentation
can develop into a wide spectrum of ichthyosis
phenotypes as the child grows. Differential
diagnosis: Harlequin fetus can be easily
differentiated from collodion baby. Restrictive
dermopathy or “Stiff baby syndrome” produces
a generalized taut thick, tethered and unyielding
skin at birth which does not desiccate in the
neonatal period. Infective causes of
desquamation such as staphylococcal scalded
skin syndrome should be included in differential
• Harlequin ichthyosis (fetus) is a dramatic,
severe, and usually fatal presentation of
ichthyosis. The child is often premature and born
with massive, shiny plates of stratum corneum
separated by deep, red fissures that tend to form
geometric patterns. There are poorly developed
or absent ears and marked ectropion and
eclabium. These children are at great risk during
the neonatal period and often die shortly after
Differential diagnosis: As given for collodion
baby. A variant of infantile systemic hyalinosis
and the stiff skin syndrome (congenital fascial
dystrophy) also present with tight skin.
1. Refsum’s syndrome (Heredopathia atactica
• Refsum’s syndrome is a rare autosomal
recessive metabolic disorder in which
there are characteristic neurological and
cutaneous clinical features:
• The underlying abnormality is deficiency
of enzyme phytanic acid oxidase.
• As a consequence of this deficiency,
phytanic acid (found in green vegetables)
accumulates and displaces some of the
unsaturated fatty acids, such as linolenic
acid, from the lipids through out the
• It manifests usually in the second decade.
• Skin is affected by an ichthyosis very
similar to ichthyosis vulgaris.
• Neurological changes include a cere-
bellar degenerative disorder (cerebellar
ataxia), a progressive polyneuropathy,
retinitis pigmentosa, and a sensory
deafness. Rarely, cardiac abnormalities
have been described.
• Diagnosis—Histopathology of the skin
shows some of the epidermal cells
containinglipid vacuoles. No or very little
phytanic acid is present in the blood.
• Treatment by a phytanic acid free diet, in
which green vegetables and dairy
products are excluded, has been used.
2. Sjögren’s-Larsson syndrome:
• This uncommon neuroectodermal
genodermatosis appears to be inherited as
an autosomal recessive disorder.
• The underlying metabolic defect is
deficiency of enzyme fatty alcohol:
Essentials in Dermatology160
• The skin disorder becomes evident after
the first few months of life with scaling
over the body and hyperkeratosis of palms
• The neurological component usually
starts at 2-3 years of life and remains static
after puberty, consists of a spastic diplegia
(Fig. 16.10), or occasionally a tetraplegia
with mental retardation. Other features
are seizures and degeneration of retina.
• Diagnosis—Histopathological changes
are similar to lamellar ichthyosis.
• Treatment—Diet lacking natural fat and
3. KID syndrome:
• The acronym KID—Keratitis, Ichthyosis,
and Deafness describes the salient clinical
features of this syndrome.
4. Netherton’s syndrome:
• It is a rare autosomal recessive disorder
characterized by concurrence of ichthyosis
linearis circumflexa, trichorrhexis
invaginata (bamboo hair) and atopic
5. CHILD syndrome:
• The acronym CHILD describes a very rare
disorder comprising Congenital Hemidy-
splasia with Ichthyosiform erythroderma
and unilateral Limb Defects mainly
6. IBIDS syndrome (Tay’s syndrome):
• The acronym IBIDS describes Ichthyosis,
Brittle hairs, Impaired intelligence,
Decreased fertility and short Stature.
The distinction between dry skin (xerosis) from
environmental causes and acquired ichthyoses
is sometimes difficult. The sudden onset of
generalized pronounced ichthyoses in an adult
could be due to:
1. Lymphomas especially Hodgkin’s lymphoma
2. Internal malignancy
3. Malabsorption syndromes and malnutrition
4. Certain drugs like clofazimine
6. Lepromatous leprosy
7. HIV disease.
• Emollients for scaly skin especially after bath
• Salicylic acid, urea, lactic acid in ointment
mixture for topical application
• Oral retinoids – Etretinate or Acitretin. They
are really useful in lamellar and congenital
• It is disorder of keratinization with an
autosomal dominant mode of inheritance
• Onset is during puberty when dirty, warty,
greasy papules appear in the seborrheic
distribution (Figs 16.11 to 16.13)
• In due course of time, the lesions grow in size
and form malodorous, papillomatous and
Fig. 16.10: Sjögren's-Larsson syndrome—child
having spastic diplegia with ichthyosis
Keratinization Disorders 161
Figs 16.11 and 16.12: Darier's disease—dirty, warty greasy papules in seborrheic distribution over the trunk
Fig. 16.13: Darier's disease—dirty, warty greasy papules in
seborrheic distribution over the scalp and face
• Other features include palmar pits (Fig. 16.14)
and ‘V’ shaped nicking of nails.
• Oral cavity shows cobble stone appearance
of the mucosa (Fig. 16.15).
• Acral areas may demonstrate dome shaped
papular lesions known as acrokeratosis
verruciformis of Hopf (Figs 16.16 and 16.17)
• Exacerbation occurs following sun exposure
• Histopathology shows dyskeratosis (corps
ronds and grains) and acantholysis.
Differential diagnosis: Well developed cases
distinctive; early lesions confused with other
follicular keratoses. Same histologic picture can
be seen in Grover’s disease as well as epidermal
naevi and acquired acanthomas, so clinico
pathologic correlation required.
Treatment: Acitretin 25-50 mg daily is probably
the best treatment; should be used until disease
brought under control and then stopped if side-
effects develop. Topical retinoids and keratolytics
Fig. 16.11 Fig. 16.12
Essentials in Dermatology162
Fig. 16.14: Darier's disease—palmar
keratoses with pits
Fig. 16.15: Darier's disease—cobblestone
appearance of hard palate mucosa
Figs 16.16 and 16.17: Darier's disease—acrokeratosis verruciformis of Hopf lesions over the dorsa of hands
are disappointing at best. Some patients improve
and use sun screens.
• It is a chronic progressive disease which
• Porokeratosis of Mibelli is the most common
prototype of porokeratosis
• The lesions are slightly atrophic plaques
surrounded by elevated keratotic wall with a
• Various types of porokeratosis are
porokeratosis of Mibelli, disseminated
superficial actinic porokeratosis, palmo-
Fig. 16.16: Fig. 16.17
Keratinization Disorders 163
plantar porokeratosis, porokeratosis
palmoplantaris et disseminata and linear
porokeratosis (Fig. 16.20).
• Histological hallmark is the column of
parakeratosis known as ‘cornoid lamella’.
Differential diagnosis: Multiple lesions can be
mistaken for psoriasis, lupus erythematosus,
pityriasis rubra pilaris or verrucous lichen planus.
Solitary lesions often misinterpreted as tinea,
warts, or actinic keratoses. Palmoplantar lesions
are hard to diagnose clinically; one can consider
Fig. 16.18: Porokeratosis of Mibelli—an atrophic
plaque surrounded by elevated keratotic wall with a
Fig. 16.19: Porokeratosis of Mibelli—ridge made
prominent by gentian violet paint
Fig. 16.20: Linear porokeratosis—
involving the arm
punctate palmoplantar keratoderma, arsenical
keratoses and warts; only biopsy provides the
Treatment: Cryotherapy, CO2 and pulsed dye
laser therapy or other destructive methods can be
used for limited lesions. Porokeratosis is usually
resistant to treatment but in some cases retinoids
(acetretin) or PUVA have been used with success.
PALMOPLANTAR KERATODERMA (PPK)
Palmoplantar keratoderma means thickening of
palms and soles. They can inherited as well as
acquired. Inherited PPK can be classified based
on the presence or absence of transgradiens
(spreading of keratoderma on to the extensor
• Transgradiens is seen in Mal de Meleda,
Vohwinkel’s, Greither’s and Papillon-Lefevre
• Transgradiens is not seen in Thost-Unna
(most common diffuse palmoplantar
keratoderma), Vorner (diffuse PPK with
• The important features of various inherited
PPK are given in the following table.
Essentials in Dermatology164
Type of keratoderma Important features
Thost –Unna (AD) Diffuse PPK with livid red border (Fig. 16.21) Marked hyperhidrosis
Vorner type (AD) Diffuse PPK similar to Thost –Unna type.Histology shows epidermolytic
Vohwinkel’s type (AD) Honey combed palmoplantar thickening with constriction bands and mutilation, star
fish shaped keratosis on dorsa of hands and fingers (Fig. 16.22)
Mal de Meleda (AR) Palmoplantar keratoderma in a glove like distribution. Erythema is prominent with
hyperhidrosis and malodor
Greither (AD) Diffuse PPK that is progressive. Extensor surfaces of hands, knees and elbows
shows psoriasiform plaque (Fig. 16.23)
Olmsted syndrome (S) Congenital PPK with perioral hyperkeratosis. Spontaneous amputation can occur
Papillon-Lefevre (AR) PPK associated with periodontosis and increased frequency of pyogenic infection
Note: AD—Autosomal dominant, AR—Autosomal recessive, S—sporadic occurrence
Fig. 16.21: Palmoplantar keratoderma—diffuse
keratoderma localized to palms
Fig. 16.22: Palmoplantar keratoderma—leading on
Fig. 16.23: Palmoplantar keratoderma—extending
onto dorsa of hands and feet (transgradien
focal kertodermas, striate keratodermas and
puntate keratodermas (Fig. 16.24).
• Various causes of acquired keratoderma are
pityriasis rubra pilaris, malignancy (Tylosis),
myxedema, Darier’s disease, keratoderma
climactericum, psoriasis, lichen planus, and
Treatment: Topical keratolytics, vitamin D3
analogues and mechanical debridement useful.
Some cases respond to oral isotretinoin.
Keratinization Disorders 165
Acanthosis nigricans is a nonspecific reaction
pattern involving major body folds and
mucocutaneous regions characterized by
hyperpigmented, velvety, soft, verrucous lesions
in a symmetric fashion (Fig. 16.25).
• It is broadly divided into benign and
• Benign acanthosis nigricans involves limited
body areas and is less severe than malignant
• The various benign forms that are the most
common include benign familial acanthosis
nigricans, acanthosis nigricans associated
with various syndromes, endocrine disease
(especially insulin resistance diabetes
mellitus, HAIR-AN syndrome [Hyper
Androgenism, Insulin Resistance, and
Acanthosis nigricans]), obesity (pseudo-
acanthosis Nigricans) and drugs (Nicotinic
acidic, fusidic acid, stilbestrol, oral
Fig. 16.24: Punctate keratoderma—punctuate
keratotic lesions involving palmar creases
Fig. 16.25: Acanthosis nigricans—hyperpigmented,
velvety, soft, verrucous involvement of neck
• Malignant acanthosis nigricans is associated
with extensive, widespread lesions and
mucosal involvement. They may precede,
follow or occur simultaneously with onset of
malignancy. Thickening of palms, especially
fingertips produces accentuated dermato-
glyphics with deep sulci called as Tripe
• Gastric carcinoma is the most commonly
associated tumor; other sites include
the bronchus, pancreas, ovary, bile duct,
Differential diagnosis:Confluent and reticulated
papillomatosis, tinea versicolor, X-linked
ichthyosis, retention hyperkeratosis, dirty neck
of atopic dermatitis.
Treatment: As it is a reaction pattern to some of
the underlying conditions, treatment need to be
directed at them. Topical retinoids may bring
Essentials in Dermatology166
Angioedema and Pruritus
URTICARIA AND ANGIOEDEMA
Is a dermal vascular reaction of the skin
characterized by the appearance of itchy wheals,
which are elevated (edematous), pale or
erythematous, transient and evanescent plaque
lesions. These lesions usually do not last beyond
24 hours. They change in size and shape by
peripheral extension or regression during few
hours (Figs 17.1 and 17.2). Wheals itch. The
intensity of itch varies.
Angioedema (Quincke’s Edema)
Is also a vascular reaction, which involves
subcutaneous or submucosal tissues (rather than
dermis in urticaria) so skin overlying the swelling
Figs 17.1 and 17.2: Urticaria—showing itchy erythematous wheals of various shapes and sizes
Fig. 17.1 Fig. 17.2
Urticaria, Angioedema and Pruritus 167
is normal in color and margins of swelling are
indistinct (diffuse swelling). It commonly results
in asymptomatic swelling of the lips (Fig. 17.3),
may develop respiratory distress. Gastro-
intestinal involvement may cause vomiting and
Angioedema may be classified into hereditary
angioedema [Type I (85%)-C1 esterase inhibitor
absent, Type II (15%)-C1 esterase inhibitor not
functional] and acquired angioedema (Acute
angioedema due to allergic IgE mediated, e.g. due
to drugs, food, insects, contact dyes, serum
sickness, cold urticaria or Chronic recurrent
angioedema-(Idiopathic in most cases; rarely due
to acquired C1 esterase inhibitor deficiency).
Urticaria may be acute or chronic
Means urticaria of less than 6 to 8 weeks duration.
Common causes are drugs especially penicillin,
foods, especially shell fish, and rarely infections.
In India, insect bites are another important cause.
No apparent cause can be found in at least half of
acute attacks. Even if a cause can be identified
and withdrawn, it is often several days before the
If urticaria lasts for more than 6 to 8 weeks
duration, it is called chronic urticaria. Culprit in
the great majority of cases remains obscure. Up to
55% of patients with chronic idiopathic urticaria
possess functional IgG antibodies directed
against the high affinity IgE receptors or less
commonly against IgE itself. These auto-
antibodies release histamine from human skin
mast cells and blood basophils and appear to be
the cause of the disease (autoimmune urticaria).
Immunoglobulin and complement components
may be deposited perivascularly, and can be
visualized by direct immunofluorescence
Basic pathogenic mechanisms of urticaria are
immune and nonimmune mechanisms. Immune
mechanism consists of type I hypersensitivity
mechanism (IgE mediated), through complement
activation, immune complex mechanism, or
autoimmune process. Nonimmune mechanism
works through direct release of histamine and
various mediators from mast cells, vasoactive
stimuli, aspirin, dietary pseudoallergens and due
to angiotensin converting enzyme inhibitors.
Etiological Factors(6 I’s + others )
a. Foods – cheese, eggs, nuts, fish, mush-
b. Food additives – tartarzine dyes, etc.
c. Food preservatives
d. Drugs – penicillin, salicylates, sulphon-
a. Insect bites
b. Injection – drug, sera, blood, etc.
• Pollens, animal dander, etc.
4. Infestation by parasites
Fig. 17.3: Angioedema—swelling of chin and lip of
Essentials in Dermatology168
Fig. 17.4: Dermographism–stroking the skin with
blunt metallic instrument resulted in an exaggerated
triple response forming wheals along them
Fig. 17.5: Cold urticaria—ice cube test producing
• Round worm.
5. Infection –focus in teeth, tonsils, sinuses or
6. Implants—prosthetic and hormonal
7. Physical causes/factors (Urticarial attacks are
brief lasting for 30 to 60 minutes):
the skin with blunt metallic instrument
results in an exaggerated triple response
b) Pressure urticaria–pressure
c) Cholinergic urticaria–increase in core
body temperature (manifest as small
intensely pruritic papules)
d) Cold urticaria–cold air or water (Fig. 17.5)
e) Heat urticaria–heated object
f) Solar urticaria–sun exposure
g) Exercise induced–exercise
h) Aquagenic pruritus/urticaria–contact
i) Vibratory urticaria–handling vibratory
8. Contact urticaria – Contact urticaria refers to
a wheal and flare reaction following external
contact with a substance, e.g. on coming in
contact with potato, onion, nitrogen mustard,
etc. develops urticaria at site of contact. It
usually appears within 30 minutes and clears
completely within hours without residual
signs of irritation.
9. Rule out underlying collagen vascular
disorders, malignancy or any psychogenic
10. Chronic idiopathic urticaria (CIU), defined as
and itching for at least 6 weeks, with no
obvious cause. Idiopathic – no cause found.
Fig. 17.6: Proceeding in a case of urticaria
Urticaria, Angioedema and Pruritus 169
How to proceed in a case of urticaria?
1. Urticaria due to physical causes or drugs
excluded by history and examination (Fig.
2. Complete food elimination followed by
gradual introduction of one dietary element
at a time helps in detection of food induced
3. Mask use/nasal filter use/change of place
may work for inhalants.
4. Stool examination by concentration method
on 3 consecutive days – infestations are
detected and treated accordingly.
5. Look for a focus of infection. If not possible to
detect, give a course of antibiotics. Still no
response, change the antibiotic.
6. The major advance in our understanding of
chronic idiopathic urticaria (CIU) in recent
years has been the discovery that in 30-50% of
patients with so labeled chronic idiopathic
urticaria, the disease is due to an autoimmune
process, and therefore is not strictly
7. The autologous serum skin test is a useful
screening test for autoimmune chronic
urticaria (AICU). In this test, 0.05 ml of the
patient’s serum, removed during a period of
disease activity, is injected intradermally into
the same patient’s uninvolved forearm skin,
along with equal volumes of saline and
histamine (10 µg/ml) at adjacent sites. The
test is read 30 min later. A positive result is
recorded if the diameter of the wheal at the
serum-injected site is 1.5 mm greater than that
of the bleb at the saline-injected site. The
sensitivity and specificity of the test are
65-81% and 71-78%, respectively. Patients
with AICU are more treatment-resistant, and
their disease runs a more aggressive course,
than those with non-autoimmune CIU.
8. If still getting urticaria, then look for other
causes and treat symptomatically.
Differential Diagnosis of Urticaria
Includes all dermatologic conditions with an
urticarial vasculitis, insect bite reactions (papular
urticaria), acute febrile neutrophilic dermatosis,
pre bullous pemphigoid, acute facial contact
dermatitis, erythema multiforme, collagen
vascular disease, porphyria, pityriasis rosea,
psoriasis and last but not least scabies.
Differential Diagnosis of Angioedema
Infections (cellulitis), trauma, superior vena cava
syndrome, subcutaneous emphysema,
Melkersson –Rosenthal syndrome.
• Minimize heat and stress,
• Avoid alcohol, NSAIDs and opiates.
• Soothing lotions such as calamine for topical
application given during attack of urticaria.
H1 antagonists or
H2 antagonists or
Old sedative antihistaminics are still better
during acute episodes.
• Corticosteroids may be required to tide over a
crisis-tapering regime commencing with
30 mg prednisolone daily, with or without
concurrent H1 antagonist administration.
• Adrenaline used in anaphylaxis.
• Other measures like intravenous fluids,
oxygen use may be required.
• Antihistamines still remain the mainstay of
• Doxepin 25 to 50 mg at night time may be
• Corticosteroids-occasionally as short tapering
courses given in autoimmune chronic
Essentials in Dermatology170
urticarias as they fail to respond to
• Cyclosporine-2.5 to 5 mg /kg body weight/
day is another option. Control of urticaria
usually occurs within 1 week of commencing
• Intravenous immunoglobulin.
• Other drug treatments are ketotifen (1-2 mg
agonist (terbutaline 2.5 mg three times daily),
calcium channel blockers (nifedipine),
leukotriene antagonists (montelukast,
zileuton), and anti IgE monoclonal antibody.
Pruritus may be defined simply as that
unpleasant sensation which produces the desire
to scratch. It may be localized or generalized. If
cause. Certain areas of the skin, particularly
susceptible to pruritus are ear canals, perianal
and genital areas, eyelids, etc. Localized pruritus
may give clues to the etiology and is less likely to
be associated with widespread or systemic
disease. In the scalp, pruritus may be due to
psoriasis or an ongoing folliculitis, in the inguinal
pruritus scroti, venereal diseases, ectoparasites
(scabies, pediculosis), in the hands and feet due
to psoriasis, pompholyx, contact dermatitis, in the
mid back due to notalgia paresthetica, macular
amyloidosis, and in the lower limbs in older
patients due to asteatosis.
Causes of pruritus can be classified as follows:
1. Dermatological disorders
2. Systemic diseases
3. Psychogenic pruritus
4. Iatrogenic pruritus.
Common dermatoses known to produce pruritus
are scabies, pediculosis, insect bites, eczema,
urticaria, prickly heat, lichen planus, dermatitis
herpetiformis, bullous pemphigoid, psoriasis,
seborrhoeic dermatitis, dermatophytosis (tinea),
urticaria pigmentosa, varicella and rubella,
papular and pruritic eruption seen in AIDS
Three important systemic disorders most likely
to play role in acquired acute pruritus are renal
disease, hepatic disease and abnormalities of the
• Renal – chronic renal insufficiency
• Hepatic – intrahepatic and extrahepatic
biliary obstruction (cholestasis).
• Abnormalities of the hematopoietic system
– iron deficiency anemia, polycythemia vera
(is associated with bath pruritus), leukemia,
Hodgkin’s lymphoma, mycosis fungoides,
mast cell disorders.
• Endocrine – diabetes mellitus, myxoedema,
• Intestinal parasites – infestation with
hookworm, round worm, pin worm.
• Collagen vascular disorders – SLE, sicca
• Neurological –multiplesclerosis,braintumor.
Psychosomatic disorders resulting in itch
commonly occur in the middle aged or older
Commonly induced by opium alkaloids, CNS
stimulants, antidepressants, and belladona
History and clinical examination is of paramount
importance. In addition, investigations outlined
Urticaria, Angioedema and Pruritus 171
below may be undertaken to find the underlying
1. Hemogram including ESR.
2. Liver function tests.
3. Kidney function tests.
4. Urine examination for albumin, sugar and
5. Blood sugar.
6. Stool examination for occult blood, worms
7. Chest X-ray.
8. Thyroid function tests.
9. Hepatitis C screening.
10. HIV testing.
11. Uric acid estimation and also acid phos-
12. Skin biopsy for mast cells and immuno-
13. Patch testing, photopatch testing, immuno-
14. Screening for underlying malignancy.
15. Serum protein electrophoresis.
1. Eliminate causative disease if possible or treat
2. Avoid provocative influences:
• Friction from rough clothing.
• Overheating and vasodilatation, e.g. alcohol,
• Keep nails short.
• Soothing lotions, e.g. calamine in urticaria,
moisturisers for dry skin.
• Occlusive bandaging may be done to retain
moisture in the skin.
• Emollients of bland nature, e.g. coconut oil,
• 1% menthol in 90% ethanol is of significant
• Steroid creams.
• Topical antipruritic drugs, e.g. doxepin,
• Avoidance of strong soaps in elderly
3. Systemic treatment:
H1 antagonists-especially sedative ones
may be preferred
Sometimes required to control urticaria
4. Specific treatments:
For uremic pruritus- Naltrexone (50 mg
oral daily), activated charcoal, UVB
For cholestatic pruritus- cholestyramine,
phenobarbitol, UVB phototherapy, rifampicin
(300-450 mg daily), naltrexone (50 mg oral
daily), and danazol.
For hematologic disease-cimetidine,
cyproheptadine, pizotifen (0.5 mg three
times daily), danazol, interferon alpha 2b,
UVB phototherapy, iron replacement
Lidocaine and intralesional steroids (for
localized pruritus and trigger points) may be
tried as last resort.
Essentials in Dermatology172
Drug Eruptions, Erythema Multiforme,
Stevens-Johnson Syndrome, and
Toxic Epidermal Necrolysis
• A drug may be defined as a chemical
substance, or combination of substances,
administered for the investigation,
prevention or treatment of diseases or
symptoms, real or imagined.
• Drug eruptions are some of the most
common skin disorders.
• They are seen in 2 to 3% of hospitalized
• These eruptions may closely mimic other skin
Characteristics of Drug Eruptions
1. There is a history of drug intake preceding
the eruption. The history of drug intake must
include all systemic drugs, nonprescription
drugs, home remedies and topical
medications. A previous history of allergic
reaction may increase the risk of
development of an allergic reaction.
2. Drug eruption is sudden in onset.
3. Generalized eruption is often pruritic.
4. Eruption is bilateral and symmetrical,
exception to this is fixed drug eruption.
5. Regression of eruption occurs on withdrawal
6. Similar type of rash recurs on re-exposure to
the same or similar drug.
Undesirable cutaneous or mucocutaneous
reactions to systemically absorbed drugs occur
through two mechanisms.
1. Immune mechanisms: All the four
hypersensitivity mechanisms may be
Type I – IgE dependent reactions cause
urticaria, pruritus, bronchospasm and
laryngeal edema within minutes, hours
Type II – Cytotoxic reactions may cause
Type III – Immune complex dependent
reactions result in serum sickness,
urticarial or leukocytoclastic vasculitis
within a week or so.
Type IV – Cell mediated immune response
may lead to eczematous and other types
of eruptions in 3 to 4 weeks time.
2. Non-immune mechanisms: They include
drug induced hemolysis (G6PD deficiency),
mast cell degranulation (codeine,
radiocontrast media), exacerbation of disease
(psoriasis by lithium or beta blocker), drug
deposition in skin, alopecia, etc.
Drug Eruptions, Erythema Multiforme, Stevens-Johnson Syndrome 173
• Drug allergy is most frequent in older
individuals and may be related to
development of immune response and
increased exposure to drugs.
• Topical application of drugs has the greatest
propensity to induce allergy, followed by the
intravenous route and the oral route.
• The drugs most often responsible for the
eruptions are antimicrobials and antipyretic/
• The appearance of the eruption may provide
some clues to its cause (e.g. fixed drug
eruptions associated with sulphonamides).
• Always keep in mind the fact that drug
eruptions are great imitators of other skin
• The most common morphologic patterns of
drug eruptions are exanthematous (40%),
along with urticaria and/or angioedema
(37%), fixed drug eruption (6%), erythema
multiforme and others.
Types of Drug Eruptions
1. Exanthematous eruptions (Maculopapular
eruptions) (occur within 1 week).
2. Urticarial eruptions.
3. Serum sickness.
4. Acneiform eruptions (Fig. 18.1).
5. Drug hypersensitivity syndrome.
6. Lupus like eruptions.
7. Lichenoid eruptions.
8. Pityriasis rosea like eruptions.
9. Phototoxic (Fig. 18.2)and photoallergic
10. Vesicobullous eruptions.
11. Eczematous eruptions.
13. Skin pigmentation.
14. Vasculitic eruptions.
15. Fixed drug eruptions.
17. Erythema multiforme.
18. Stevens-Johnson syndrome.
19. Toxic epidermal necrolysis.
Exanthematous eruptions: These are the most
frequent of all cutaneous reactions to drugs, and
usually appear within 1 week of the causative
drug being started. A rash may also start within
4-7 days of the offending drug being stopped.
Lesions most often start first and clear first from
head and upper extremities. They may be
accompanied by fever, pruritus and eosinophilia.
Antibiotics especially semisynthetic penicillins
and sulfonamides are the most common causes
of this reaction pattern.
Fig. 18.1: Acneiform drug eruption—
monomorphous papular eruption over the back
Fig. 18.2: Phototoxic drug eruption—exaggerated
sunburn reaction limited to exposed areas
Essentials in Dermatology174
Urticarial eruptions: It is the second most
common type of cutaneous drug eruption.
Angiotension converting enzyme inhibitors are
the frequent causes of angioedema often without
Serum sickness-like reaction: Serum sickness-
like eruption consists of fever, a rash with usually
urticarial features and arthralgias occurring
within 1 to 3 weeks of initiation of the drug.
Lymphadenopathy and eosinophilia may also be
Drug hypersensitivity syndrome (DHS): Also
known as drug rash with eosinophilia and
systemic symptoms (DRESS) syndrome or as
drug induced delayed multiorgan
hypersensitivity syndrome (DIDMOHS). It
consists of an exanthema, hepatitis and fever.
Eighty percent of the cases have an exanthem
type eruption whereas others will develop more
serious Stevens Johnson syndrome. DHS may be
life threatening and requires prompt
discontinuation of the drug and systemic
Fixed drug eruption: It differs from other
eruptions in that it occurs and then recurs at fixed
sites. Single or multiple circular or oval
erythematous macule/s or plaque/s develop
with burning or stinging sensation (Fig. 18.3).
These lesions sometime develop into bullous
lesions (Fig. 18.4) and when they heal leave
behind slate gray colored pigmentation (Fig.
18.5). Mucocutaneous junctions are commonly
Erythroderma: It is a generalised erythema,
infiltration and scaling of the skin (involving
more than 90% of the surface area of the body).
It may be a manifestation of a drug eruption but
usually occur due to dermatological disorders
like psoriasis, contact dermatitis, pityriasis rubra
Fig. 18.3: Fixed drug eruption—typical slate grey
oval macule with halo of erythema over the trunk
Fig. 18.4: Fixed drug eruption–circular, slate gray
colored pigmented macular lesion developing bullae
Fig. 18.5: Fixed drug eruption—multiple fixed drug
eruptions over the chest
Drug Eruptions, Erythema Multiforme, Stevens-Johnson Syndrome 175
Erythema multiforme: Erythema multiforme is
characterized by many types of lesions including
urticaria, target lesions (iris lesions or bull’s-eye
lesions) (Figs 18.6 and 18.7) and vesicles and
bullae, bilaterally symmetrically over acral areas
of the body. They may also involve mucous
Stevens-Johnson syndrome: It is a severe form
of erythema multiforme associated with
constitutional symptoms (fever) and visceral
organ involvement, e.g. kidneys. The skin as well
as mucous membranes are both involved (Figs
18.8 and 18.9).
Toxic epidermal necrolysis (TEN): The term
toxic referred to a presumed toxin responsible
for the prodrome and the eruption, epidermal
to the presence of significant epidermal damage
and necrolysis to the pathologic findings of
necrosis and clinical findings of epidermolysis.
It is a potentially life threatening, severe
mucocutaneous reaction pattern characterized
by fever, systemic toxicity, erythema and
tenderness of skin followed by flaccid bullae
formation resembling a burns case (Fig. 18.10).
Nikolsky’s sign is positive. Mortality from TEN
is 11 to 33%.
Fig. 18.6: Erythema multiforme—chest showing
typical target lesions
Fig. 18.7: Erythema multiforme—target lesions
showing three zones of color
Fig. 18.8: Stevens-Johnson syndrome—facial
eruption with hemorrhagic crusting of lips
Fig. 18.9: Stevens-Johnson syndrome—atypical
target lesions over the back
Essentials in Dermatology176
Diagnosis is basically based on suspicion and
history of drug intake. A thorough and stepwise
approach is essential to proper diagnosis of a
drug- induced skin reaction. First step in patient
evaluation should include (1) a comprehensive
drug history, (2) awareness of various clinical
manifestations of drug allergy and cutaneous
reaction, (3) awareness of factors that favor
development of allergic reactions to drugs, and
(4) awareness of the immunologic and
nonimmunologic mechanisms involved in
cutaneous reaction to drugs. A general rule of
thumb is that drugs started within one week of
the onset of the eruption are the most likely
Second step is skin biopsy and in vivo testing.
This includes patch testing, scratch/ prick
testing and dechallenge/ rechallenge tests.
Dechallenge/ rechallenge continues to be
regarded as the most definitive method for
ascertaining drug-induced reactions. However,
it is often not an option if the patient has
experienced a life threatening condition or if
suspected agent cannot be continued. Blood
work-up may also aid in the clinical diagnosis.
A CBC with differential count may show atypical
lymphocytosis, leukopenia, leukocytosis,
eosinophilia and so on. Liver function tests,
serum creatinine, urinanalysis and TSH may be
indicated in patients with suspected drug
induced hypersensitivity syndrome.
Third step is the invitro testing which include
Radio Allergosorbent Assays (RAST) and
Enzyme Linked Immunosorbent Assays
(ELISA). Other tests include Lymphocyte
Transformation Test (LTT), Macrophage
migration Inhibition Factor (MIF), Lymphocyte
Toxicity Assay (LTA), Basophil Degranulation
Test and Histamine Release tests.
Consider differential diagnoses such as
infections, collagen vascular disease, primary
skin conditions and neoplasia. Culture of skin,
blood, tissue, erythrocyte sedimentation rate,
ANA, and other tests may be ordered to help
confirm or rule out other conditions. If palpable
purpuric lesions are present, a complete physical
and laboratory examination is required with an
eye towards ruling out vasculitic involvement
of other organ systems and other causes of
vasculitis such as infections or collagen vascular
• Withdrawal of all drugs
• Antihistamine (H1 antagonists)
• Soothing lotion for topical application
• Corticosteroids – topical steroids may
provide some relief. Systemic corticosteroids
are indicated if signs and symptoms are
• Adrenaline in case of anaphylaxis
• Other measures like fluid and electrolyte
balance maintenance, wet compresses, etc.
It is a self limited, usually mild but relapsing
exanthematic reaction of skin probably triggered
by circulating immune complexes, most often
related to recurrent herpes simplex infection,
Fig. 18.10: Toxic epidermal necrolysis—sheets of
necrotic tender epidermis over the back
Drug Eruptions, Erythema Multiforme, Stevens-Johnson Syndrome 177
characterized by skin lesions with varied
morphology (typically target lesions) in acral
areas, frequently associated with mucous
• Herpes virus infection is the single most
important cause of erythema multiforme
• Other important agents include Mycoplasma
pneumoniae, drugs and malignancies.
• EMF is common in young adults.
• Prodromal symptoms are minimal to absent.
• The lesions seen are urticarial papules, target
lesions, vesicles and bullae.
• The lesions occur in a symmetric fashion on
the extensor aspects of limbs, palms and
• The target lesions /iris lesions have three
zones of color: The central dark cyanotic area,
pale edematous zone and the surrounding
erythema (Figs 18.6 and 18.7).
• The iris lesions result from centrifugal
spread of a red maculopapule as the center
becomes cyanotic, purpuric or vesicular.
Urticaria, urticarial vasculitis, figurate erythemas
(slow evolving lesions, usually asymptomatic, no
mucosal involvement), acute febrile neutrophilic
dermatosis, disseminated lesions of contact
dermatitis, bullous pemphigoid, linear IgA
dermatosis, herpes gestationis, lupus
erythematosus, exanthematous or morbilliform
drug eruption (accompanied by fever, pruritus,
eosinophilia, involving trunk and extremities,
sparing the face and pressure areas, fade with
desquamation and postinflammatory hyper-
pigmentation), viral exanthem (start on face and
involve the trunk, maculopapular/ urticarial/
vesicular/petechial lesions associated with fever,
conjunctivitis, and lymphadenopathy, fades
without pigmentation and scaling), fixed drug
eruption (solitary first, later new lesions appear
with repeated attacks, common on limbs, hands
and feet, genitalia and perianal area, also
periorbital and perioral), Kawasaki’s disease
(lips are red, dry with crust, transient red
macules, conjunctivitis without exudates,
strawberry tongue, lymphadenopathy),
paraneoplastic pemphigus (severe necrosis of
lips, eyes, oral mucosa, with polymorphous skin
lesions, biopsy shows acantholysis and
immunofluorescence confirms the diagnosis),
Stevens Johnson syndrome (severe episodic
acute mucocutaneous reaction, most often
elicited by drugs and occasionally by infections,
characterized by rapidly expanding irregular
macules or atypical target lesions involving body
surface area less than 10%, involvement of more
than 2 mucosal sites), toxic epidermal necrolysis
(mucosal erosions and epidermal detachment
more than 30% of body surface area, skin
tenderness, Nikolsky’s sign positive,
histopathology shows full thickness epidermal
necrosis with subepidermal cleft formation),
acute graft versus host disease (also precipitating
factor for Stevens Johnson syndrome, similar
lesions, histopathology also can’t differentiate,
lesions begin over the palms and soles first) and
acute hemorrhagic edema of infancy (is a
manifestation of leukocytoclastic vasculitis in
infants and small children, it is characterized by
symmetric erythematous and purpuric
concentric rings in acral locations similar to
target lesions that spontaneously resolve in about
• Treatment is symptomatic. If the herpetic
lesions are clinically evident, acyclovir needs
to be given.
TOXIC EPIDERMAL NECROLYSIS
Stevens-Johnson syndrome (SJS) and Toxic
epidermal necrolysis (TEN) are closely related
severe acute mucocutaneous intolerance
reactions most often elicited by drugs and less
so by infections (Table 18.1).
Essentials in Dermatology178
Table 18.1: Differentiating features between erythema multiforme and SJS-TEN
Features Erythema multiforme SJS-TEN
1. Etiology HSV (in majority) Drugs (80-95%)
2. Course Acute, self limited, recurrent Acute, self limited, episodic
3. Prodrome Absent to moderate Intense, skin tenderness
4. Eruption Disseminated, symmetric, acral, face Disseminated, confluent, symmetric,
on face, neck, trunk
5. Typical lesions Fixed plaques, target lesions, blisters, Macules, flat atypical target, central
Nikolsky’s sign –ve necrosis, Nikolsky’s sign +ve
6. Mucosal involvement Frequent, mild oral Prominent, severe, 2-3 mucosal
7. Body surface area <10% <10% to >30%
8. Constitutional symptoms Absent to moderate Prominent to severe
9. Pathology Satellite cell necrosis, DEJ blister formation, Massive keratinocyte necrosis,
prominent mononuclear cell infiltrate, papillary sloughing of epidermis, dermal
dermis edematous infiltrate slight to absent
10. Internal organs Not involved Not infrequent
11. Duration 1-3 weeks > 2-6 weeks
12. Complications None Septicemia, pneumonia,
gastrointestinal hemorrhage, renal
and cardiac failure
13. Mortality rate 0% 1-50%
14. Healing Without scarring Sequelae due to mucosal scars
They have been classified based on the area
• SJS— mucosal erosions and epidermal
detachment below 10%.
• SJS/TEN overlap— mucosal erosions and
epidermal detachment between 10-30%.
• TEN— mucosal erosions and epidermal
detachment more than 30% .
STEVENS-JOHNSON SYNDROME (SJS)
• The important drugs causing SJS are
phenytoin, phenobarbitone, sulfonamides,
penicillins and NSAID’s.
• It is common in children and young adults.
• The disease is preceded by a nonspecific
prodrome with fever, myalgia, rhinitis and
• Skin lesions occur abruptly and are purpuric
macules, atypical target lesions and papules.
• Bullous lesions may occur in oral, genital and
• Ulcerative stomatitis with hemorrhagic
crusting is the most characteristic feature
• Corneal erosions may lead to symblepharon,
synechiae and opacities.
• Constitutional symptoms may be severe
during active stages.
• Differential diagnosis: As given for erythema
• The treatment includes immediate withd-
rawal of all potential causative agents, skin
care, fluid and electrolyte balance, eye care,
supportive care with antibiotics, diet and
others. Patients have to be managed in an
intensive care set up. Specific medications
include steroids, intravenous immuno-
globulins, plasmapheresis, hemodialysis,
cyclophosphamide, and cyclosporine.
Drug Eruptions, Erythema Multiforme, Stevens-Johnson Syndrome 179
TOXIC EPIDERMAL NECROLYSIS
TEN is a rare life threatening mucocutaneous
reaction characterized by widespread sheets of
erythema, necrosis and bullous detachment of
• Incidence: 1 to 3 cases per million.
• Pathogenesis: In predisposed patients, the
drug metabolites may bind to epidermis and
trigger an immune response leading to
immunoallergic cutaneous adverse reaction.
• Drugs causing TEN are antiepileptics
(phenytoin, phenobarbital, carbamazepine),
sulfonamides, ampicillin, allopurinol,
antituberculous drugs (thiacetazone,
isoniazid) and NSAID’s.
• TEN begins with sheets of erythema covering
• In hours, the skin lesions become painful and
extremely tender and small vesicles and
bullae appear over the involved skin (Fig.
• The epidermis can be separated from dermis
by slight tangential pressure (Nikolsky’s
• Mucosal erosions and conjunctival erosions
are a constant feature.
• Septicemia and bronchopneumonia are the
important causes of death.
• As given for erythema multiforme.
Staphylococcal scalded skin syndrome (SSSS)
can be differentiated from TEN by occurrence
in children, absence of mucosal lesions and
absence of systemic features. Moreover in
SSSS, the involved skin is dry and
parchment- like while in TEN it is
erythematous, purpuric and necrotic.
Physical and chemical injury such as scalding
and burns, solar erythema and chemical
burns are other differential diagnosis,
difficult in an unconscious patient.
• Patients have to be managed in an intensive
care set up with proper maintenance of fluid
and electrolytes like Stevens Johnson
• Role of steroids is controversial.
• Intravenous immunoglobulins have been
found to be useful.
• Plasmapheresis, hemodialysis, cyclophos-
phamide, cyclosporine, N-acetylcysteine,
thalidomide, etc are other treatment options.
Essentials in Dermatology180
DISORDERS OF THE SEBACEOUS
Acne vulgaris is a self-limited disease, seen
frequently in adolescents, primarily involves the
sebaceous follicles. Most cases of acne are
pleomorphic, presenting with a variety of lesions-
comedones, papules, pustules, nodules, and as
sequelae to active lesions-pitted or hypertrophic
Four major factors are involved in the
1. Increased sebum production
2. Hypercornification of the pilosebaceous duct
3. Microbial flora
Increased Sebum Production
more sebum than normal subjects and the level of
secretion correlates with the acne severity.
Hypercornification of pilosebaceous ducts
presents histologically as microcomedones and
Disorders of Sebaceous,
Eccrine andApocrine Glands
clinically as blackheads and whiteheads. Thus
comedones represent the retention of
hyperproliferating ductal keratinocytes in the
Acne is not infectious. However, three major
organisms isolated – Propionibacteria (P. acnes,
P. granulosum, P. avidum), Staphylococcus
epidermidis and Malassezia furfur. Environment of
bacteria (i.e. low pH, reduced oxygen tension and
bacterial lipases, proteases, etc.) more important
than absolute numbers.
in the dermis but from inflammatory mediators
that diffuse from the follicle where they are
produced by P. acnes.
• Usually starts in adolescence and resolves by
• At least some degree of acne affects 95% and
83% of adolescent boys and girls.
• At the age of 40 years, acne may persist in 1%
of males and 5% of females.
Disorders of Sebaceous, Eccrine and Apocrine Glands 181
• Occurs predominantly on the face (99%), back
(60%) and chest (15%). Infraorbital area
spared even in severe acne.
• Two types of lesions:
i. Non-inflammatory (comedones)
• Comedones are the pathognomoniclesions of
with a broad base and a plugged apex. Two
types of comedones – blackheads/open
comedones (black color due to oxidation of
melanin) and whiteheads/closed comedones.
• 25% of the whiteheads resolve within three
• Inflammatory lesions include papules,
pustules and nodules or nodulocystic lesions
(Figs 19.2 and 19.3).
• Nodules occur more frequently in males and
may be interconnected with sinuses.
• In its most severe variant, acne can present
with cysts and abscesses.
• Some amount of scarring in 90%. These could
be hypertrophic scars, keloids, atrophic scars
or ice-pick scars.
open and closed comedones are present, with
few inflammatory papules), moderate (with
erythematous papules and pustules which are
the predominant lesions, and disease is
limited to the face), moderately severe (with
erythematous papules, pustules, and nodules
that are present on the face), and severe (with
multiple painful nodules that are present on
the back in spite of aggressive topical and oral
interventions, respond only to isotretinoin).
Acne is rarely misdiagnosed. The commonest
mistaken diagnosis is rosacea (has facial flushing,
typically pustules occurring over erythematous
background, localization of lesions to mid-face,
Fig. 19.1: Acne vulgaris–face showing comedones,
papules, and pustules
Fig. 19.2: Acne vulgaris–face showing comedones,
papules, pustules and nodules
Fig. 19.3: Acne vulgaris–nodulocystic lesions in
addition to other acne lesions over the cheek
Essentials in Dermatology182
absence of seborrhea, comedones, nodules, cyst
or scarring). Perioral eczema/dermatitis can be
confused with acne in females, but lesions itch,
the skin is dry and there are no comedones.
Whiteheads may be confused with milia (which
are predominantly infraorbital in distribution and
are whiter). Acneiform drug eruptions are sudden
onset, follicular monomorphous eruptions
characterized by papules and pustules
resembling acne, induced by skin exposure to
various industrial chemicals or medications.
Folliculitis due to Gram-negative organisms can
complicate acne therapy and rarely folliculitis due
to Candida may also present as multiple pustular
eruptions as may S. epidermidis folliculitis.
Demodex folliculitis can present as non-
responsive acne, which best responds to
metronidazole or topical permethrin. Rarely acne
vulgaris need to be differentiated from Pityro-
sporum folliculitis, acne agminata, adenoma
sebaceum lesions of tuberous sclerosis,
pseudofolliculitis barbae, plane warts,
acneiform eruption of Behcet’s disease.
Treatment involves counseling, acne assessment
and appropriate and ethical prescribing based
on the history, acne severity, lesion type and the
psychological effects of the disease. The various
modalities of treatment can be classified into
topical and systemic therapies (Table 19.1).
• Predominantly comedolytic:
– Tretinoin (0.025%, 0.05%, 0.1% creams,
gels) (reduce number of existing
comedones and prevent formation of new
comedones by loosening ductal kerati-
nocytes) - The best treatment for
comedones. Almost every patient benefits
from topical retinoids.
– Adapalene (0.1% cream, gel, solution).
– Azelaic acid (20% cream).
• Predominantly antimicrobial:
– Clindamycin (1% gel, solution).
– Erythromycin (1.5-2% gel, solution,
– Benzoyl peroxide (2.5-10% gel, lotion,
– Sodium sulfacetamide- sulphur combi-
• Predominantly anti-inflammatory
– Topical antibiotics.
– Combination preparations.
– Zinc and erythromycin.
– Benzoyl peroxide and erythromycin.
• Oral antibiotics (oral tetracycline 250-500 mg
1-4 times a day, oral minocycline 50-100 mg
daily, doxycycline 50-100 mg daily,
erythromycin 250-500 mg 2-4 times a day,
trimethoprim 300 mg twice a day, pulse
dosing with azithromycin -250 mg daily for
three days in a week for 4-6 months or
• Hormones (anti-androgens like 2 mg
estradiol, flutamide-250 mg twice a day, oral
contraceptive pills, spironolactone 100-200
for women with acne located primarily on the
lower face and neck, those with PCOS and
late onset acne, late onset adrenal hyperplasia
or other identifiable endocrinologic con-
• Isotretinoin: It is the only anti-acne agent that
affects all four of the known major etiologic
mechanisms: sebum production, comedo-
genesis, Propionobacterium acnes (P. acnes)
colonization of ductal and skin surface, and
monocyte chemotaxis-induced inflammation.
It is indicated for nodulocystic acne, acne
Disorders of Sebaceous, Eccrine and Apocrine Glands 183
conglobata, acne fulminans, moderate acne
relapse, significant psychosocial impairment,
marked concomitant seborrhea, Gram-
negative folliculitis, and scarring or persistent
dyschromia. Acne therapy is usually initiated
at a dose of 0.5 mg/kg daily for the first
2-4 weeks and then increased to 1.0 mg/kg/
day for the remainder of the 20 weeks course.
The chance of a prolonged remission is greater
of body weight is achieved.
• Corticosteroids (co-prescribed with
isotretinoin in severe acne variants).
• Oral zinc.
• Dapsone (nodulocystic acne).
• Clofazimine (acne fulminans).
• NSAIDs (to reduce inflammation).
• Chemical peels.
• Blue light therapy.
• Comedone extraction.
• Aspiration of cysts.
• Incision and drainage (large cysts).
• Intralesional steroid (0.1 ml triamcinolone
Acne Scar Surgery
• Laser abrasion.
• Chemical peels.
Course and Prognosis
The course and prognosis of acne is highly
variable. All acne causes scars.
ACNE VARIANTS WITH MARKED
It is a rare type of acne, which is highly
inflammatory and presents with comedones,
nodules, abscesses and draining sinus tracts.
Healing occurs with severe scarring. It usually
starts in adult life. Oral isotretinoin is the best
treatment for patients in whom antibiotics are
unsuccessful or in patients with very severe deep
acne like this one.
Follicular Occlusion Tetrad (Acne tetrad)
It is a combination of acne conglobata, acne
inversa/hidradenitis suppurativa, dissecting
cellulitis of scalp and pilonidal sinus. It is more
common in men.
It is characterized bySynovitis, Acne (conglobata,
fulminans), Pustulosis (pustular psoriasis,
palmoplantar pustulosis), Hyperostosis and
It is characterized by the sudden appearance of
severe acne with systemic signs and symptoms
(fever, leukocytosis, osteomyelitis, polyarthralgia,
Table 19.1: Treatment guidelines for acne vulgaris
Grade 1(Mild) Grade II-III(Moderate) Grade IV(Severe) Maintenance therapy
Topical retinoids Topical retinoids Isotretinoin or Topical retinoids + BPO
Benzoyl peroxide BPO or topical A/B Topical retinoids,
(BPO) or topical oral A/B, hormone
antibiotic (A/B) + therapy
Essentials in Dermatology184
polymyalgia). The disease exclusively occurs in
teenage boys. The face is often not involved.
Treated initially with high dose corticosteroids
to control inflammation and then retinoids
SPECIAL TYPES OF ACNE
Acne from Drugs and Chemical Agents
Due to topical or systemic glucocorticoids,
anabolic steroids, INH, cyclosporine, iodides and
bromides, lithium, etc.
It is due to lubricating and cutting oil application
predominantly as comedones.
Chloracne or Industrial Acne
It is due to topical or systemic exposure to toxic
chlorinated hydrocarbons and causes severe
It is seen in young women. Small acne spots are
picked, squeezed and altered by manual
interference. Resulting papules are crusted and
It is a centrofacial disease, which is characterized
by papules and papulopustules against a vivid
erythematous background with telangiectases,
preceded by episodes of flushing (Fig. 19.4). Later,
there may be diffuse hyperplasia of connective
tissue with enlarged sebaceous glands,
particularly of the nose (rhinophyma). Women
are more often affected than men in their third
and fourth decade.
Ophthalmological complications are
common, occurring in over 50% of the patients
with rosacea. These include sensation of grittiness
or irritability of the eyes, often accompanied by
visible reddening of the conjunctiva. Blepharitis,
keratitis, episcleritis, chalazion, and hordeolum
are also common.
Important differential diagnoses include acne
vulgaris (typical acne lacks the redness,
telangiectasia, and flushing of rosacea), lupus
erythematosus (DLE—scarring, scaling and
follicular plugging are not features of rosacea,
SLE-butterfly erythema is not pustular and is
usually associated with systemic symptoms),
perioral dermatitis (lesions itch, the skin is dry),
seborrhoeic dermatitis (scaling in typical
seborrhoeic areas) and demodex folliculitis
pernio) is the differential diagnosis for
Papulopustular rosacea responds well to
treatment. Topical treatment with metronidazole
(1% cream, 0.75% gel, cream, lotion) is effective.
Additional topical therapies reported as effective
include tetracycline, clindamycin, erythromycin,
azelaic acid 20% cream and 15% gel, 0.025%
Fig. 19.4: Rosacea—face showing erythema
topped by erythematous papules and pustules
Disorders of Sebaceous, Eccrine and Apocrine Glands 185
retinoic acid and 10% sulphur cream. Topical
imidazoles are also gaining popularity in the
treatment of rosacea.
Effective oral treatment includes tetracycline
or oxytetracycline 250 mg twice daily and
erythromycin 250 mg twice daily. More recently
developed tetracyclines such as minocycline,
lymecycline and doxycycline are often used. Oral
metronidazole (750-1500 mg in divided doses) is
also effective. Oral isotretinoin (10-60 mg/day) is
an alternative in resistant rosacea and can even
Flushing and burning are the most difficult
features of rosacea to treat. Non-cardioselective
beta-blockers such as propranolol 40 mg twice
daily or nadalol 40 mg daily, clonidine 50 mcg
twice daily, and rilmenidine 1 mg daily.
Advent of vascular laser and intense pulsed
light sources has provided a range of highly
effective treatments for ablation of telangiectasia.
Surgical treatment is a very successful
treatment in rhinophyma. Excellent cosmetic
results can be obtained by scalpel or razor
remodeling, electrocoagulation, cryosurgery,
excision and vaporization with argon, carbon
dioxide or Nd: Yag lasers.
It is facial dermatosis predominantly affecting
females of childbearing years. The dermatosis is
characterized by an erythematous, micropapular,
fine scaling eruption classically affecting the
nasolabial folds, chin, and upper lip, sparing a
patient, there is striking dependency on topical
steroids. A frequently heard story is that the
patient presents with the earliest signs of rash
and is given a potent topical steroid. The
condition then shows improvement but any
attempt to stop the treatment dramatically
worsens the condition after a few days.
The important differential diagnoses include
rosacea (usually no telangiectasia or flushing in
perioral dermatitis), lip licking cheilitis (seen
predominantly in 7-15 years old age group, the
rash is caused by repeated licking of skin around
the mouth and is marked by a scaling, pink band
around the mouth and involvement of lips),
seborrhoeic dermatitis (not usually circumoral
and the scalp, ears and eyebrows are commonly
involved), contact allergic dermatitis (does not
vulgaris (evidence of comedones, large papules
and cysts in wider distribution and responds
to distinguish if confined to perioral area but can
be differentiated histologically) and facial Afro-
Caribbean childhood eruption (FACE) (do not
spare the perilabial skin, pustules do not occur,
occur often in males).
The most important measure is usually to
discontinue the application of the topical
an initial flare may develop after the withdrawal
of a topical corticosteroid. A four week course of
oral tetracycline or its analogues such as
minocycline, doxycycline or lymecycline is
usually all that is required. Topical metronidzole,
topical erythromycin, and topical tetracycline
have also been used.
DISORDERS OF ECCRINE SWEAT
Disorders of eccrine sweat glands may be broadly
classified into four-chromhidrosis, hyperhidrosis,
hypo- or anhidrosis and miliaria.
It means secretion of colored sweat. It is an
exceedingly rare functional disorder of the
Essentials in Dermatology186
apocrine sweat glands. The colored sweat may
be yellow (most common), blue, green, or black.
Colored sweat fluoresces and is caused by
lipofuscin. Topical capsaicin satisfactorily
reduces facial and nipple chromhidrosis.
It means excessive sweating which could be
localized or generalized. It may occur as
consequence of a number of causes. Most
commonly excessive sweating of the palms and
soles occurs during mental stress, and may be
associated with tachycardia and vasomotor
This type of hyperhidrosis is usually localized to
the palms, soles or/and axillae. Frequently there is
a family history and commonly begins in
childhood or around puberty. There is a tendency
of spontaneous improvement after the age of 25
years. Sweating may be intermittent (triggered by
anxiety, stress, or fear) or may be constant.
Apart from the embarrassing nature of the
disorder, complications include pompholyx,
contact dermatitis, and pitted keratolysis.
Sweating on the lips, forehead and nose after
eating certain foods is known as gustatory
sweating. Gustatory sweating may be idiopathic,
post-peripheral nerve injury (parotid surgery,
auriculotemporal nerve syndrome or von Frey
syndrome, cervical sympathectomy), sensory
Topical anticholinergics (0.5% glycopyrronium
bromide cream), formalin 1% soaks, glutar-
aldehyde 10% in a buffered solution, 20%
aluminium chloride have been used. Ionto-
phoresis either using tap water or anticholinergic
drugs like glycopyrronium bromide is a
satisfactory method. Direct current is usually
used, with each palm or sole being treated for 30
min with 20 mA initially three times a week.
Botulinum toxin injection into 4 cm2
areas on the
palms, soles or axillae dramatically reduces
sweating. The hypohidrosis continues for an
average of 7 months. Axillary hyperhidrosis may
be effectively controlled by excision of the most
active sweating portion of the axillary skin,
alternatively liposuction removal may be used.
It can result from poral occlusion, congenital or
acquired absence of sweat glands, damage to
sweat gland function or dysfunction of
sympathetic nerves in neuropathies. It may be
localized or generalized.
within the skin. It manifests with a variety of signs
and symptoms. Miliaria crystallina (Sudamina)
consists of non-inflammatory, superficial
subcorneal translucent vesicles that easily
rupture when rubbed with a finger. Miliaria rubra
(prickly heat) causes pruritic inflammatory
papules around the sweat pores, follows repeated
Some of the eruptions of miliaria rubra become
pustular resulting in miliaria pustulosa. Miliaria
profunda results when sweat leaks into the
dermis and presents as multiple discrete, flesh
The most common complications of miliaria
are secondary infection and disturbance of heat
regulation.Periporitis staphylogenes is the name
given to multiple staphylococcal abscesses
superimposed on miliaria rubra in young infants
(Fig. 19.5). Postmiliarial hypohidrosis invariably
occurs following miliaria and sweating may be
depressed to half the normal amount for as long
Disorders of Sebaceous, Eccrine and Apocrine Glands 187
as 3 weeks following miliaria. Affected persons
may show decreasing efficiency, irritability,
anorexia, drowsiness, vertigo and headache.
Tropical anhidrotic asthenia is a rare form of
miliaria with long lasting poral occlusion, which
produces anhidrosis and heat retention.
The most effective treatment is to place the patient
in a cool environment as this will avoid further
sweating. Avoidance of excessive clothing,
friction with clothing, excessive use of soap and
contact of the skin with irritants will reduce the
incidence. Calamine lotion is effective in the relief
of discomfort. Oral ascorbic acid 500 mg twice
daily has been found to diminish the severity of
DISORDERS OF APOCRINE GLAND
The capacity to produce an unpleasant odor is
best-known property of apocrine gland.
Physicians in the past relied heavily on detecting
special body odors in diagnosis of diseases, e.g.
fruity odour in diabetic coma, butcher shop odor
in yellow fever, freshly baked bread odor in
typhoid fever, etc.
Fig. 19.5: Miliaria complicated by secondary
infection of sweat glands—periporitis
Bromidrosis (Bromhidrosis or
Excessive odor arising from apocrine sweat, also
known as fetid sweat or malodorous sweating. It
is chiefly encountered in axillae. Often the patient
complains of offensive axillary sweat but actually
have no offensive odor. The complaint represents
a phobia, delusion, paranoia or a lesion of the
central nervous system. True bromidrosis is
usually not recognized by the patient. Anti-
bacterial soaps, deodoarants, frequent bathing,
changing of underclothes, shaving of the axillae
and application of aluminium chloride are all
Fish Odor Syndrome
Affected individuals are unable to oxidize tertiary
trimethylamine produced by oxidation of choline
and carnitine in food. This results in formation of
fish) sweat. Defect in flavin containing
monooxygenase 3 (FMO3) gene causes the
disease. Diet low in carnitine and choline may
Coloured apocrine sweat.
Fox Fordyce Disease
It is a disorder of the apocrine sweat gland
comparable to prickly heat of the eccrine glands.
It is a chronic itchy papular eruption of apocrine
gland bearing areas-axillae (Fig. 19.6) and pubic
area, classically seen in women between the ages
of 15 and 35 years. Pruritus is often exacerbated
by emotional or physical stimuli of the apocrine
Includes lichen planus, lichen nitidus, infective
folliculitis, chronic dermatitis, and syringoma.
Essentials in Dermatology188
Estrogen therapy in the form of oral contraceptive
pills is universally effective. Topical tretinoin,
tried. Treatment response with topical steroids or
intralesional steroids is not satisfactory.
Hidradenitis Suppurativa (Apocrinitis,
Hidradenitis Axillaris, Acne Inversa)
It is a chronic and cicatricial disease of apocrine
gland bearing skin areas-axillae, anogenital skin
(Fig. 19.7). The disease occurs in both sexes,
usually in the second or third decade. It is rare
before puberty. Affected patients are often
A solitary abscess in the early stage resembles a
carbuncle, lymphadenitis, or an infected
Fig. 19.6: Fox Fordyce disease–chronic itchy
papular eruption in the axilla of a female
epidermoid cyst. Other dermatoses that produce
fistulas and sinuses should be excluded, such as
scrofuloderma, actinomycosis, tularemia, and cat
scratch disease. In the inguinal region,
lymphogranuloma venerum, granuloma
inguinale, Crohn’s disease, and ulcerative colitis
should be excluded.
Earliest lesions often heal quickly with
intralesional steroid therapy. Concomitant use of
antibiotics (minocycline, cephalosporins,
ciprofloxacin) is recommended. Isotretinoin (1
disease, removal of the affected area is often
required. Wide local excision and healing by
second intention is considered the surgical
treatment of choice.
Fig. 19.7: Hidradenitis suppurativa—nodules,
sinuses and puckered scarring in the axilla
Disorders of Hair and Nails 189
DISORDERS OF HAIR
scarring or non-scarring.
Diffuse Non-scarring Alopecia
1. Androgenetic alopecia: Terminal hair is
converted into vellus hair. In men, recession of
the frontal hairline near the temples and thinning
over the vertex occurs (Fig. 20.1). In women, the
scalp hair is generally diffuse but more so in the
Treatment includes in males- topical
minoxidil (2 and 5% solution) or oral
finasteride – competitive inhibitor of type II 5
α-reductase -1 mg/day and in females –
topical minoxidil 2% and antiandrogens
(spironolactone, cyproterone acetate,
flutamide) and surgical treatment such as
scalp reduction and hair transplantation.
2. Endocrine and nutrition related: Endocrine
abnormalities of the thyroid, pituitary or adrenals
can cause diffuse alopecia. Malnutrition and zinc
deficiency or iron deficiency may also cause
3. Telogen effluvium: Certain events can induce
hair follicles to enter the telogen phase. This then
Disorders of Hair and Nails
induces a synchronous growth of hair follicles
6-10 weeks later such that more synchronous hair
high fever, surgery or other stress. Drugs such as
enalapril, beta blockers, retinoids, oral
contraceptive pills, lithium, levodopa may be
responsible. Treatment is reassurance, removal
of stress or drug responsible. Hair density usually
returns to normal in 6-12 months.
Fig. 20.1: Androgenetic alopecia—scalp showing
receding frontal hairline
Essentials in Dermatology190
4. Anagen effluvium: Abrupt cessation of hair
growth follows use of cytotoxic drugs
colchicine, vitamin A, etc.
Patchy non-scarring alopecia
• Alopecia areata is an unpredictable usually
patchy, non scarring hair loss condition. The
word alopecia is derived from the Greek,
“Alopex”, meaning “Fox mange” (baldness).
Any hair bearing surface may be affected.
• It is a common condition, probably auto-
immune in etiology. Associated autoimmune
diseases are Hashimoto’s disease, vitiligo and
• It affects men and women equally.
• It generally starts in the 2nd or 3rd decade.
Patients are frequently quite young, sixty
percent of them present before 20 years of age.
• The characteristic initial lesion is commonly
a round or oval, totally bald, smooth patch
involving the scalp (Figs 20.3 and 20.4) or any
hair bearing area on the body.
• A frequent feature in an alopecia areata patch
is “Exclamation mark” hairs that are broken
Fig. 20.2: Anagen effluvium – diffuse non-scarring
alopecia following use of cytotoxic drugs
Fig. 20.3: Alopecia areata – rounded bald smooth
patches over the scalp
Fig. 20.4: Alopecia areata – many bald patches
coalescing over the scalp
Disorders of Hair and Nails 191
short hairs tapering proximally. The pull test
may be positive at the margins of the patch
indicating very active disease.
• Alopecia areata progresses as a wave of
follicles, enter telogen prematurely.
• The scalp is the most common site but any site
can be involved. When the perimeter of the
from its resemblance to a snake) (Fig. 20.5),
which is associated with poor prognosis.
• Alopecia areata can occur as diffuse loss of
hair from the scalp but spares the grey hair
• If there are multiple patches on the scalp, they
may become confluent to result in total loss of
hair from the scalp, called as alopecia totalis
(Fig. 20.7). Total loss of hairs from the whole
body is called alopecia universalis.
• Nail dystrophy is associated with alopecia
areata in 10 to 66% of cases. Nail pitting
“Hammered brass” (Fig. 20.8), trachyonychia
(longitudinal striations), Beau’s line,
onychorrhexis, thinning or thickening,
onychomadesis, punctate or transverse
Fig. 20.5: Alopecia areata—ophiasis pattern
Fig. 20.6: Alopecia areata—diffuse hair loss
sparing grey hair
Fig. 20.7: Alopecia totalis
Fig. 20.8: Alopecia areata – fine pitting of nail
Essentials in Dermatology192
leukonychia, red spotted lunula and nail
dystrophy may be seen in the nails.
Classification of Alopecia Areata
According to Pattern
1. Patchy alopecia areata-round or oval patches
of hair loss (most common) (Fig. 20.3).
2. Reticulated pattern of patchy hair loss (Fig.
3. Ophiasis, a band-like alopecia areata, hair
loss occurs in the parietal temporo-occipital
scalp (Fig. 20.5).
4. Ophiasis inversus(sisaipho), a rare band like
pattern of hair loss in the frontal parieto
temporal scalp (the exact opposite of ophiasis)
5. Diffuse alopecia areata, a diffuse decrease in
hair density over the entire scalp.
According to the Extent of Involvement
1. Alopecia areata, partial loss of scalp hair
2. Alopecia totalis, 100% loss of scalp hair (Fig.
3. Alopecia universalis, 100% loss of hairs on
the scalp and body.
Indicators of a Poor Prognosis
1. Underlying atopy
2. The presence of other autoimmune diseases
3. Family history of alopecia areata
4. Young age at onset
5. Nail dystrophy
6. Extensive hair loss
The characteristic non scarring patchy loss of
hairs, the presence of exclamation point hair on
the periphery, a hair pull test indicating telogen
hair excess and in atypical cases skin biopsy
showing specific findings (a peribulbar and at
the lower one third of the follicle, a lymphocytic
infiltrate, “swarm of bees”, with no scarring) all
points towards the diagnosis.
Alopecia areata needs to be differentiated from
tinea capitis, trichotillomania and secondary
syphilis (moth-eaten appearance in beard or
• Various modalities of treatment are available,
the simplest of which are the use of counter
irritants like phenol, benzoyl, tincture iodine,
dithranol, etc. Physical modalities like UVB
in erythema doses, grenz rays and thorium
X-ray may be used with varied success.
• Considering the autoimmune etiology of the
disease various immunosuppressive drugs
have been used. Among them, corticosteroids
are important which can be used topically,
intralesionally and systemically.
• Photochemotherapy, contact immunotherapy
(using dinitrochlorobenzene [DNCB], squaric
acid dibutylester [SADBE], diphencyprone),
topical minoxidil or topical cyclosporine may
Course and Prognosis
Alopecia areata, however, a serious cosmetic
problem, has unpredictable course.
Tinea capitis: Discussed earlier under
• It is the term (Greek-“hair pulling
madness”) first used by the French
dermatologist Hallopeau to denote “a
morbid impulse to pull one’s own hair”.
• It manifests as one or a few small oval
patches of hair loss which may occur in
any hair area of the body in children or
• The patches are unusually irregular,
asymmetric, and ill defined and have
many broken hairs.
• Common sites of involvement include
scalp (Fig. 20.9), eyebrows, eyelashes, and
Disorders of Hair and Nails 193
• Trichophagy is rarely reported with
trichotillomania, and when it occurs,
trichobezoars (obstructive hair balls in the
gastrointestinal tract) are the most severe
• Clinical differentiation from scalp alopecia
areata is usually based upon the presence
of short, broken hairs within the patch,
and more irregular, often angular outlines
of the area. Differentiation from tinea
capitis may require Wood’s light
examination, potassium hydroxide, or
culture. The scalp in trichotillomania is
usually healthy with broken hairs rather
than scaly or erythematous in tinea capitis.
• Any method of preventing grasping of
hairs for a period of time (restraint, heavy
gloves) will clarify the diagnosis and in
one way serve as treatment, since hairs
will grow normally in the area in the
absence of trauma. One form of treatment
consists of simply shaving the area.
Psychological intervention and drugs
such as clomipramine or fluoxetine may
Traumatic alopecia: It is due to traction or
Secondary syphilis: Moth-eaten alopecia may be
Patchy/Diffuse Scarring Alopecia
1. Physical and chemical injury.
2. Infection – Kerion, favus, herpes zoster,
folliculitis decalvans (Fig. 20.10).
3. Lichen planus and DLE.
4. Pseudopelade: Pseudopelade describes a
scarring alopecia which represents the end
stage of an idiopathic or unidentified
destructive inflammatory process in the scalp.
Characteristically, involves the vertex area of
the scalp with crab like extensions (Fig. 20.11).
5. Malignancy – Basal cell carcinoma, squamous
Hirsutism: It refers to hair growth in a woman in
areas of the body where hair growth is under
androgen control and in which normally only
post-pubescent males have terminal hair growth.
These areas include the moustache, beard, chest
and inner thigh.
A. Ovarian (Polycystic ovarian disease,
Fig. 20.9: Trichotillomania – unusually irregular patchy
loss of hair over the temple area of scalp due to
pulling of hairs
Fig. 20.10: Perifolliculitis decalvans-scarring
alopecia with folliculitis
Essentials in Dermatology194
B. Drugs (androgens, oral contraceptive pills,
glucocorticoids, diazoxide, minoxidil,
C. Endocrine –Adrenal (Congenital adrenal
hyperplasia, 21 and 11 hydroxylase deficiency,
ACTH dependant Cushing’s syndrome).
Others- hypothyroidism, acromegaly and
D. Physiological – puberty, pregnancy.
Treatment includes removal of precipitating
cause/s, drug therapy with oral contraceptive
pills, spironolactone, flutamide, finasteride,
cyproterone acetate, and glucocorticoids, physical
methods such as shaving, bleaching, waxing,
laser, or electrolysis and topical therapy with
eflornithine hydrochloride cream (slows hair
growth by blocking ornithine decarboxylase).
or length beyond the accepted limits of normal
for a particular age, race, or sex. The excess hair
may be generalized or localized and may consist
of lanugo, vellus, or terminal hair.
DISORDERS OF NAILS
Nails may show their abnormalities—in shape,
surface and color.
Fig. 20.11: Scarring alopecia of scalp-crab like
extensions over the scalp-pseudopelade
A. Shape Abnormalities
Anonychia: It means absence of nails. Usually a
Clubbing: It means increased transverse and
longitudinal curvature of nails with hypertrophy
of the soft tissue components of the digit pulp
(Fig. 20.12). To confirm it, one can oppose dorsal
aspects of two fingers from opposite hands,
between the two opposed nails normally a
window of light is seen which get obliterated in
• Cyanotic Heart Disease
• Lung disease (hypoxia, lung cancer,
bronchiectasis, cystic fibrosis)
• UC/Crohn’s disease
• Biliary cirrhosis
• Birth defect (harmless)
• Infective endocarditis
• Neoplasm (esp. Hodgkin’s)
• GI malabsorption.
Koilonychia: Reverse curvature in the
longitudinal and transverse axis of nail gives a
Fig. 20.12: Clubbing of nails
Disorders of Hair and Nails 195
concave dorsal aspect to the nail, such nail is
thought to have koilonychia (Fig. 20.13).
Commonly, it is due to iron deficiency anemia.
Macronychia and micronychia: Too large or too
small nail in comparison with other nails of digits.
Onycholysis: Distal or lateral separation of the
nail from the nail bed (Fig. 20.14). May be seen in
psoriasis, onychomycosis, etc.
Fig. 20.13: Koilonychia—spoon like deformity of
Fig. 20.14: Onycholysis with pitting of finger nails in
Fig. 20.15: Onychogryphosis – thickened great toe
nail growing upwards
Pterygium: When a central fibrotic tongue like
band from proximal nail fold joins the nail bed
dividing the nail proximally into two, it is known
as pterygium. For example, it occurs in lichen
Subungual hyperkeratosis: It means excessive
collection of squamous debris under the free edge
of the nail. For example, it occurs in psoriasis,
Onychogryphosis: Here nail gets thickened and
grows upwards in a spiral manner attributed to
chronic trauma (Fig. 20.15).
Pachyonychia congenita: Here hypertrophy of
nails is associated with nail bed and hyponychial
hyperkeratosis (Figs 20.16 and 20.17).
B. Surface Abnormalities
Beau’s lines: They are transverse grooves on nails
which arise out of temporary interference with
nail formation (Fig. 20.18).
Pitting: These are punctate erosions on the nail
surface (Fig. 20.14). Commonly seen in psoriasis,
and alopecia areata.
Median canaliform dystrophy: Nail shows
Essentials in Dermatology196
nail and involvement is symmetrical.
Onychoschizia: It is characterized by transverse
splitting of nail into layers at or near the free edge
of the fingers and toes.
Onychauxis: Nail plate appears to be thickened
due to subungual hyperkeratosis of nail bed seen
in psoriasis, eczema, distal subungual
Onychoclasis: Breaking of the nail.
Onychomadesis: Separation of the proximal part
of nail plate from the matrix and bed with
subsequent shedding of nail.
Onychomalacia: Softening of nail.
Onychorrhexis: Longitudinal ridging and
fissuring of nail plate with brittleness and
Trachyonychia: Nails are rough and often
thinned (20 nail dystrophy or sand paper nail)
seen in alopecia areata, lichen planus, psoriasis,
C. Color Abnormalities
Color changes in nail may be due to exogenous
causes or endogenous causes.
Leukonychia: This term is used for white
discoloration of nails attributable to nail matrix
Melanonychia: Means streaky hyperpigmen-
tation of nails.
Figs 20.16 and 20.17: Pachyonychia congenita—thickening of nails with subungual hyperkeratosis
Fig. 20.18: Beau’s lines—transverse depressions
equidistant from the nail folds
Fig. 20.16 Fig. 20.17
Disorders of Hair and Nails 197
Terry’s nail: Nail is white proximally but normal
distally. It occurs in congestive cardiac failure,
cirrhosis or adult onset diabetes mellitus.
Red lunulae: Nail shows erythema of all or part
of lunula. Mostly affects thumb nail. Dotted red
lunula occurs in psoriasis. Other causes are
congestive cardiac failure, cirrhosis of liver,
systemic lupus erythematosus, etc.
Splinter hemorrhages: They represent
longitudinal hemorrhages in the nail bed,
may occur in dermatoses like psoriasis,
dermatitis, fungal infection or systemic diseases
like endocarditis, systemic lupus erythematosus,
mycosis fungoides, rheumatoid arthritis, etc.
Half and half nails: It is onychopathological
index of renal diseases and nail exhibits either
normal or whitish proximal half and distinctly
abnormal, brownish distal portion (Fig. 20.19).
Fig. 20.19: Half and half nail – proximal half white and distal half brownish
Infections of Nails and Nail Folds
Acute paronychia: It presents with painful
swelling of the nail fold. Most commonly caused
Chronic paronychia: It presents with chronic
swelling of nail folds of one or more fingers, often
middle and index fingers, and is associated with
candida and/or pseudomonas infection.
to primary inoculation of herpes simplex virus
on to the finger and presents as single/grouped
vesicles close to the nail.
Tinea unguium: It is the fungal infection of
nail complex by a dermatophyte and may be
distal subungual infection, proximal
subungual infection, or superficial white
Onychomycosis: It includes tinea unguium and
also infection by non-dermatophytic fungi
Essentials in Dermatology198
• Porphyrias arehereditary disturbances in the
synthesis of heme involving well-defined
• The term “porphyria” is derived from the
Greek word for “purple” and originally
referred to the red to purple color of the urine
of patients affected by acute intermittent
porphyria. Other forms of porphyria produce
urine that varies from pink to red to brown.
Unlike findings with hematuria and
pigmenturias (e.g., hemoglobinuria due to
hemolysis, myoglobinuria caused by
rhabdomyolysis), routine dipstick tests are
• Porphyrins also account for the fluorescence
of urine viewed with a Wood’s lamp.
• Almost all are inherited in an autosomal
dominant pattern except congenital
erythropoietic porphyria which is inherited
in an autosomal recessive manner.
• In addition, although the enzyme defects are
genetic and permanent, the symptoms are
often intermittent and do not appear until
puberty except in congenital erythropoietic
porphyria and hepatoerythropoietic
porphyria (both manifest in infancy or
childhood, resemble clinically each other).
This is true in porphyria cutanea tarda, acute
intermittent porphyria, and variegate
• Photosensitivity in porphyria is due to
absorption of UV radiation in soret band
• Factors which precipitate are four m’s:
medication (ethanol, oestrogens, iron,
hexachlorobenzene), menses, malnutrition
and medical illness.
• These disorders can be classified into those
without vesicobullous lesions and those
associated with them.
• The former includes delta aminolevulinic acid
dehydratase deficiency porphyria and acute
intermittent porphyria (have no cutaneous
manifestations), and erythropoietic proto-
porphyria (can cause photosensitivity, but
vesicobullous lesions are rare).
• The latter includes congenital erythropoietic
porphyria (Gunther’s disease), hepato-
erythropoietic porphyria, hereditary
coproporphyria, variegate porphyria (most
prevalent in white population of South Africa)
and porphyria cutanea tarda (PCT).
Metabolic and Nutritional Disorders 199
Congenital Erythropoietic Porphyria
in infancy or early childhood.
• It is the result of defective activity of the
enzyme uroporphyrinogen cosynthase.
• Clinical manifestations include severe
hypertrichosis (Figs 21.2 and 21.3),
erythrodontia (fluorescent teeth), hemolytic
anemia with splenomegaly, and bone
abnormalities. However, the first clue to the
diagnosis in infancy is generally not one of
these striking cutaneous changes, but rather
the pink or burgundy discoloration of urine
(staining of diapers) due to massive
porphyrinuria (Fig. 21.4).
Markedly elevated levels of uroporphyrin I and
coproporphyrin I in urine, stool and RBCs.
Other childhood photosensitivity disorders
• Treatment of this disorder is aimed at the
cutaneous photosensitivity or at the anemia
and its complications. Sun protection
(clothing better than sunscreens) and
portionofthephotodamage.Othermodalities,Fig. 21.1: Congenital erythropoietic porphyria–
blistering over the fingers
Figs 21.2 and 21.3: Congenital erythropoietic porphyria—a child having
photosensitivity and hypertrichosis of face and trunk
Fig. 21.2 Fig. 21.3
Essentials in Dermatology200
chronic transfusion regimens and splen-
ectomy, the risks must be weighed against the
severity of the disorder in each individual
case. Bone marrow transplantation successful
in some cases.
Porphyria Cutanea Tarda
• PCT was first recognized by Waldenstrom in
the 1930s, who identified a group of patients
with excessive porphyrins in the urine, skin
lesions in light exposed areas and a late
(‘tarda’) onset in adulthood (in contrast with
Gunther’s disease), so he called the disease
‘porphyria cutanea tarda’.
• Most common type of porphyria due to
deficiency of enzyme coproporphyrinogen
• Clinical signs include darkening of the urine
(Fig. 21.5) and cutaneous photosensitivity
manifested as fragility and bullae of sun
exposed skin, scarring (Fig. 21.6), hyper-
trichosis and pigmentary and sclerodermoid
changes. In severe cases, the clinical
appearance may be similar to that of
congenital erythropoietic porphyria.
red fluorescence. Total porphyrins and
uroporphyrins are raised in urine and plasma;
coproporphyrins raised in stool; porphobilinogen
Fig. 21.4: Congenital erythropoietic porphyria–pink
to red discoloration of urine in the test tube
Fig. 21.5: Porphyria cutanea tarda–
darkening of the urine
Fig. 21.6: Porphyria cutanea tarda–scarring and
pigmentary changes following photosensitivity
Metabolic and Nutritional Disorders 201
and delta aminolevulinic acid are normal in urine.
Immunofluorescence of skin demonstrates IgG
and other immunoglobulins at dermo-epidermal
junction, and in and around blood vessels.
Some forms of epidermolysis bullosa acquisita
look similar as does drug induced pseudo-
porphyria (usually furosemide) in renal dialysis
• Avoid hepatotoxic agents. Unlike other
porphyrias, it is usually not inherited and
responds to different treatments (venesection
and antimalarials). If hepatitis C is
documented, treat it with interferon and
PRIMARY CUTANEOUS AMYLOIDOSIS
• Primary cutaneous amyloidosis is defined as
cutaneous amyloidosis in the absence of other
systemic or dermatological disease.
• The various localized forms of primary
cutaneous amyloidoses include the more
common papular (lichen amyloidosis) and
macular types and the rare nodular or
• Single or multiple nodules involving the trunk
or limbs characterize the nodular form. It is
due to localized plasma cell dyscrasia.
characterized by numerous pruritic, brownish
lichenoid papules distributed over the
extensor surface of legs (Fig. 21.7) and
forearms and upper back.
• Macular amyloidosis typically manifests as
brownish patches with a reticulate or rippled
pattern, involving the upper back (Fig. 21.8),
arms and lower extremities.
• In some patients features of both lichen and
macular amyloidosis can coexist and the term
‘biphasic amyloidosis’ has been coined for
these. Extensive variants of both macular and
papular amyloidosis have also been
• On the other hand, amyloidosis cutis
dyschromica (ACD) is a rare distinct type of
primary cutaneous amyloidosis, which is
characterized by reticulate hyperpig-
mentation with hypopigmented spots seen
almost all over the body without any
Fig. 21.7: Lichen amyloidosis–pruritic brownish
lichenoid papules affecting the extensor aspect of
Fig. 21.8: Macular amyloidosis—rippled
pigmentation over the upper back
Essentials in Dermatology202
For macular amyloidosis is postinflammatory
hyperpigmentation, atopic dermatitis, lichen
simplex chronicus and fixed drug eruption.
lichen planus and lichen simplex chronicus.
Nodular amyloidosis, clinically needs
differentiation from naevus lipomatosus, lipoma,
of amorphous deposits, such as gout and nodular
• Treatment is symptomatic with topical
corticosteroids (under occlusion), dimethyl
sulfoxide (DMSO) and sometimes derma-
Xanthomas are composed of masses of lipid
and plaque like lesions in the skin, tendons and
sometime in the internal organs. Xanthomas are
important clinical finding as they often evolve in
the presence of elevated blood lipids and
lipoproteins. Lipoproteins are macromolecular
complexes that carry hydrophobic plasma lipids,
particularly cholesterol and triglycerides, in the
plasma. An elevation of serum lipid levels is
called hyperlipidemia, or hyperlipoproteinemia
while the term dyslipoproteinemia signifies
abnormalities in serum lipoproteins, whether or
not serum lipid levels are categorically elevated
or not. Of clinical interest is the fact that different
species of lipoproteins typically produce different
types of xanthomas. Thus, the type of xanthoma
observed in a particular patient provides
important clues as to the type of hyperlipo-
• Soft, velvety papules and plaques arranged
• Common sites – upper eyelid, inner canthus
(Figs 21.9 and 21.10)
• Signify a systemic hyperlipidemia – usually
• Usually occur in normolipidemic individuals
but may be seen in familial hypercholestero-
lemia, dysbetalipoproteinemia, mixed
hyperlipidemia. Secondary causes are
obstructive liver disease, myxedema, and
• Treatment options includes surgical excision,
electrofulguration, trichloroacetic acid
chemical cautery , and CO2 laser.
• Firm, yellow-orange, often with an erythe-
matous halo, small papules (0.5 cm in
Fig. 21.9: Xanthelasma palpebrarum Fig. 21.10: Arcus juvenilis
Metabolic and Nutritional Disorders 203
• Usually painless but may be tender on
• Sites – knees, elbows, buttocks and pressure
points, typically bilateral.
• Seen with raised LDL levels – Familial
teinemia and secondary hyperlipidemias
(hypothyroidism, chronic biliary disease)
• Slowly enlarging subcutaneous nodules
attached to tendons, ligaments, fascia and
periosteum (sub-periosteal) (Fig. 21.12).
• Overlying skin appears normal.
• Sites – extensor tendons of hands and feet,
Achilles tendon, sub-periosteal bony
prominences such as malleoli and elbows
• Occur in severe hypercholesterolemia with
raised LDL – Familial hypercholesterolemia,
less frequently in secondary hypercholestero-
• Pinhead sized asymptomatic yellow papules
with a reddish base, usually fleeting in nature
and appear in crops.
• Sites – buttocks, shoulders and extensor
surfaces of extremities (Fig. 21.13).
• Occasionally, these papules may coalesce and
overlie a tuberous xanthoma – tuberoeruptive
• Associated with pure or mixed hyper-
triglyceridemia and a high concentration of
VLDL or chylomicrons.
Fig. 21.11: Tuberous xanthomas over the buttocks Fig. 21.12: Tendinous xanthoma near the
left 5th toe laterally
Fig. 21.13: Eruptive papular and tuberous xanthomas
over the elbows and knees
Essentials in Dermatology204
• May occur in secondary hyperlipidemia of
• Yellow-orange macules or slightly palpable
• May occur at any site.
• Plane xanthomas over palmar creases –
‘xanthoma palmaris et striata’ – patho-
• Plane xanthomas may occur in secondary
hyperlipidemias (biliary cirrhosis, cholestasis,
• They appear as flat to slightly raised yellow
dermal plaques with corrugated surface
within or adjacent to finger webs (Fig. 21.14),
axillae, buttocks and antecubital and popliteal
• They are pathognomonic of type II hyper-
Generalized Plane Xanthomas
• These cover large areas of the face, neck and
thorax and also may involve flexures and
• May be associated with myeloma, macro-
globulinemia or lymphoma; rarely with
normal plasma lipids.
• 50% of patients may have hypolipidemia with
low LDL levels.
Table 21.1: Abnormalities of lipoprotein metabolism with their cutaneous features
Lipid phenotype Lipoprotein phenotype Cutaneous features
Familial hypercholesterolemia IIa Tuberous xanthomas, tendon
xanthomas subperiosteal xanthomas
Familial defective apo B100 IIa Tendon xanthomas
Polygenic hypercholesterolemia IIa Usually none
Familial hypertriglyceridemia I, V None, occasionally eruptive
Familial lipoprotein lipase deficiency I, V Eruptive xanthomas, plaques
Familial apo CII deficiency I, V Eruptive xanthomas, plaques
Hypertriglyceridemia and Hypercholesterolemia
Combined hyperlipidemia IIb Usually none;
Dysbetalipoproteinemia III Tuberous xanthomas, tuberoeruptive
xanthomas, xanthoma striata palmaris
Fig. 21.14: Intertriginous xanthomas in the finger
Metabolic and Nutritional Disorders 205
• Rare autosomal recessive disorder with
xanthomas in the tendons and the brain.
• It is due to mutation in the sterol
27-hydroxylase (CYP27A) gene leading to
defective conversion of cholesterol to bile
acids with accumulation of cholestanol.
• Severe neurologic disease and tendency to
coronary artery disease.
• Tendon xanthomas.
• Urinary gas chromatography is the specific
test for this disease.
• Treated with oral deoxycholic acid to replace
the bile acid pool.
LIPOID PROTEINOSIS (URBACH –
WIETHE DISEASE, HYALINOSIS CUTIS
• Lipoid proteinosis is a rare disorder
characterised by infiltration of hyaline
• It is inherited as a monogenetic autosomal
recessive disorder of normal chromosomal
pattern and is due to mutations in the extra-
cellular matrix protein 1 gene.
• The earliest manifestation is hoarseness that
develops in infancy, which can progress to
complete aphonia without breathing
difficulty. Examination of larynx frequently
reveals infiltration, thickening and nodularity
of cords. The mucosa of lip, pharynx and
tongue (Fig. 21.15) may also develop firm
yellow nodules giving it a cobblestone
appearance. The tongue is enlarged and firm
on palpation with decreased range of
movements. Ankyloglossia can occur due to
involvement of the lingual frenulum.
Recurrent parotitis can occur.
• In early stages, the skin lesions are crops
of bullae, pustule, that leave behind acne
like scars. Later on, patients develop hyper-
keratotic wart like or nodular skin lesions over
Fig. 21.15: Lipoid proteinosis – infiltrated lip and
dorsal aspect of hands, finger, elbows and
knees, and patchy alopecia.
margins results in typical beaded papules –
is the single most typical clinical feature of
this disease (Fig. 21.16). In later stages, there
may be total loss of eyelashes. Further
infiltration of eyelids leads to its malfunction
and can cause corneal ulcer.
• Neurological abnormalities include calcifi-
cation in the hippocampus and falx cerebri
and temporal lobe epilepsy.
Fig. 21.16: Lipoid proteinosis–beaded eyelid margins
Essentials in Dermatology206
• Drusen of Bruch’s membrane seen in fundi in
half the patients.
• Sickle-shaped calcifications dorsal and lateral
to sella turcica in skull X-ray films are
• The nature of hyaline material and underlying
metabolic defect is unknown. It may represent
an underlying lysosomal storage disorder
with single or multiple enzyme defects, others
have postulated it to be a disorder of collagen
metabolism or collagen synthesis.
• Distinctive histologic features include extreme
dilation of blood vessels and thickening of
their walls, progressive hyalinization of sweat
glands, and infiltration of the dermis and
subcutaneous tissue with extracelluar hyaline
deposits and also demonstrable in walls of
• Differentiation from erythropoietic protopor-
phyria may be difficult histologically.
Xanthomatoses and amyloidosis can be
excluded histologically. In adults, differential
diagnosis is from lichen myxoedematosus and
myxedema with hoarseness have to be
• There is presently no effective therapy for
lipoid proteinosis. Hoarseness may be
relieved temporarily by surgical removal of
vocal cord infiltrates. Facial lesions may be
treated by dermabrasion, chemical skin
dimethyl sulphoxide has been claimed to be
• Phrynoderma is a type of follicular hyper-
keratosis typically seen in vitamin A
• This eruption has also been associated with
deficiencies of vitamin B complex, C, and E,
calories, and essential fatty acids.
• The morphology of these lesions is variable
and may range from filiform papules to small
conical papules to large papules with large
horny centers. They may be of the same color
as the surrounding skin or may be slightly
hyperpigmented. Elbows (Fig. 21.17), knees,
anterolateral thighs, posterolateral superior
forearms, extensor aspect of limbs, shoulders,
abdomen, back and buttocks are the sites of
• Differential diagnosis includes keratosis
pilaris and Darier’s disease.
• The treatment is oral vitamin A 100,000 IU/
• Pellagra is a nutritional disorder that occurs
due to deficiency of niacin or tryptophan or
both. Therapy with isoniazid, 5-fluorouracil,
causes are carcinoid tumors, and Hartnup
• The term pellagra is derived from the Italian
words ‘pelle agra’ meaning rough skin.
• It is still endemic in areas of Africa and Asia
due to poor nutrition and intake of certain
cereals such as maize and jowar (Indian
millet) as staple diet.
Fig. 21.17: Phrynoderma hyper keratotic follicular
papules over the extensor aspect of the forearm
Metabolic and Nutritional Disorders 207
• In the present day context, in western world,
pellagra is confined to individuals who have
improper food intake such as psychiatry
patients, alcoholics and recluses.
• Pellagra is a clinical syndrome characterised
by (1) symmetrical photosensitive skin
eruption (2) gastrointestinal manifestations
(3) neurological and psychiatric disturbances.
These well-known group of symptoms are
traditionally remembered as pellagra’s four
D’s -dermatitis - diarrhea - dementia and
when untreated, death - is very seldom seen.
But most of the manifestations are borderline
and/ or less typical in nature.
• The initial manifestation is an erythematous,
photosensitive pruritic rash that occurs on the
dorsa of hands.
• The usual sites affected are the face, neck and
dorsal surfaces of hands, arms and feet.
• The dorsa of the hands are the most frequent
site from where it may extend up to arm to
form the ‘glove’ or ‘gauntlet’ of pellagra (Figs
21.18 and 21.19). The dermatosis is strikingly
symmetrical and clearly demarcated from the
• The feet is commonly involved and it may also
affect the front and back of the leg to form a
boot (Fig. 21.20).
• In the face, an erythematous rash extending
from the nose to the cheeks, chins, lips, may
resemble lupus erythematosus “Butterfly
rash”. Rarely eyelids and ears may be affected.
Facial rash usually occurs concurrently with
• This eruption forms a broadband or collar
around the neck, known as Casal’s ‘necklace’
(Fig. 21.19). In many instances, the necklace
has an anterior continuation, also known as
• Differential diagnosis includes drug eruption,
photodermatitis, lupus erythematosus, and
• Classical pellagra responds dramatically to
(nicotinic acid) 100-300 mg/day in three
divided doses. The mental changes disappear
within 24-48 hours but skin lesions may take
3-4 weeks to disappear.
Figs 21.18 and 21.19: Pellagra–chest and upper limb shows Casal’s necklace, and glove of hyper-
pigmented flaking dermatosis
Fig. 21.18 Fig. 21.19
Essentials in Dermatology208
• It manifests insidiously between the ages of
three weeks and 18 months (often when the
baby is switched from breast milk to cow’s
and perineum) (Figs 21.23 to 21.25) and acral
(extensor surfaces of the major joints, fingers,
and toes) dermatitis, alopecia and diarrhea
(Mnemonic DAD to remember its clinical
Fig. 21.20: Pellagra—”boot” of pellagrus
dermatosis affecting lower legs
• This syndrome occurs due to vitamin B2
(Riboflavin) deficiency and is characterized
by mucocutaneous lesions of angular
stomatitis, cheilosis, glossitis, seborrhoeic
dermatitis (especially around the nose) (Fig.
21.21), scrotal (Fig. 21.22) and vulvar
dermatitis, and increased corneal vascularity.
• It usually responds promptly and
dramatically to riboflavin supplementation
with 5 to 15 mg of riboflavin daily for 2 weeks
and correction of dietary errors.
• Acrodermatitis enteropathica, an autosomal
recessive disorder which appears to be due
to defective absorption of zinc from the
• It may be a presenting sign in cystic fibrosis or
Fig. 21.22: Ariboflavinosis–scrotal dermatitis
Fig. 21.21: Ariboflavinosis–erythema and scaling of
Metabolic and Nutritional Disorders 209
Figs 21.24 and 21.25: Acrodermatitis
enteropathica—perianal psoriasiform dermatosis
• The primary cutaneous eruption is
vesicobullous, which is symmetrical and
grouped. The lesions soon evolve into erosive
vesicobullous eruption or psoriasiform
patches. Secondary infection of skin lesions
with Staphylococcus aureus is common and
impairs wound healing.
• At the same time or shortly afterward, diffuse
loss of hair and gastrointestinal disturbances
manifest chiefly by diarrhea, occur.
• Mental depression, listlessness, loss of
appetite, perleche, photophobia, and
blepharitis may occur during exacerbations.
• Differential diagnosis includes atopic
dermatitis, seborrheic dermatitis and
• Laboratory verification of deficient plasma
or serum zinc levels may be undertaken
where facilities exist, otherwise, all these
cases respond to zinc sulphate / gluconate
(1 to 2 mg/kg body weight/day) given once
Fig. 21.23: Acrodermatitis enteropathica–
or twice daily. Skin lesions heal within one
to two weeks. Diarrhea ceases and variability
with depression of mood improves within 24
Essentials in Dermatology210
GENETICS IN DERMATOLOGY
Human genetics is the study of the range of
biological variations in human beings with each
individual showing considerable variability in
his/her expression of disease.
Human genome, the genetic material is
packaged into units called chromosomes
(Chromo-colored, somes-bodies). Each somatic
cell contains 46 including 2 sex chromosomes.
The karyotype of an individual identifies the
number and structure of chromosomes. This is
usually derived from peripheral blood cells
are classified by the position of the centromeres
and the proportion of long and short arms.
Phenotype is the bodily manifestation of
Genodermatoses are genetically determined skin
disorders, course of events altered little by
environmental agents with single gene disorders.
Familial means a condition more common in
relatives of an affected individual than in general
Inheritedmeans that disorder is transmitted from
one generation to next.
Genetics and Genodermatoses
Congenital is one that is present at/before birth,
not necessarily genetically determined.
Gene is the sequence of bases on DNA that code
for one polypeptide.
Locus is the precise position of the gene on
Alleles are genes at a single locus, which may be
heterozygous or homozygous.
Dominantmeans full effect in heterozygous state.
Expression means effects of a gene are variable.
Penetrance is the frequency with which a gene
produces an effect. If trait is non-penetrant,
expressivity is zero.
Genetic heterogeneity means similar/identical
phenotypic features associated with genes at
different loci, e.g. albinism, ichthyosis, cutis laxa,
Phenocopy means environmental causes
mimicking genetic diseases.
to primary action of an abnormal genotype, e.g.
pachyonychia congenita, neurofibromatosis.
Genetics and Genodermatoses 211
Mutation occurs due to point substitution or
deletion and may be somatic or gamete mutation.
Mosaicism relates to an individual with 2 or more
cell lines of different genotypes derived from a
Autosomal Dominant Inheritance
In this mode of inheritance, the gene locus is on
an autosome and the trait is transmitted from
generation to generation.
• Both males and females are affected in equal
• Affected individuals are heterozygous
• 50% of the children will be affected
• Severity varies considerably in the family
• Few show lack of penetrance.
Examples: Ichthyosis, tuberous sclerosis,
Autosomal Recessive Inheritance
In these pedigrees, the trait does not appear in
successive generations. Parents appear entirely
• Affected individuals are homozygous (means
one copy received from each parent “double
dose of the gene”)
• One fourth or 25% of children are affected
• No family history may be there
• High frequency of consanguinity can be
• Disorders are very severe.
Examples: Xeroderma pigmentosum, phenyl-
X-linked Recessive Inheritance
In these conditions, the trait does not appear in
• Males are uniquely affected, whereas female
siblings are carriers of the trait. Affected males
are in different generations
• Females are healthy carriers, pass on disease
to ½ of their sons and ½ of their daughters are
• All of the daughters of an affected male are
obligate carriers of the trait
• Mother’s brothers are affected
• Family history always not positive.
Examples: Fabry’s disease, Menkes-Kinky’s
X-linked Dominant Inheritance
Successive generations show the trait.
• Females are predominantly affected
• There is family history of recurrent losses of
pregnancy early on. Although the losses may
not be identified, it is often the case that the
male fetus is preferentially aborted.
• Hemizygous are males and heterozygous
females. In most X-linked dominant traits the
hemizygous male is more severely affected
than the heterozygous affected female
• Affected males transmit disorder to all his
daughters, but none of his sons
• Affected females transmit disease to ½ of their
sons and ½ of their daughters.
Example: Incontinentia pigmenti.
In single gene traits, transmission follows
Mendel’s classical laws. In multifactorial
inheritance, often referred to as polygenic
inheritance, a definite familial tendency for
development of the trait exists but the proportion
of affected relatives is much less than expected
for a single gene trait. Multiple genes modified by
environmental factors influence the expression
of the characteristic.
Genetic counseling is the process undertaken to
help patients to better understand the genetic
basis of a medical problem and to plan for the
future. By this definition, genetic counseling
Essentials in Dermatology212
includes helping the patients to comprehend the
medical facts, including the diagnosis, the
probable course of the disorder and available
management, the hereditary basis of the disorder,
and the risk of recurrence in specific relatives. The
of action that seems appropriate in view of the
risk and the family goals.
Symbols in Common use in Preparation
of a Family Pedigree
Neurofibromatosis Type 1 (NF-1)
• Neurofibromatosis type1 (NF-1), also known
as von Recklinghausen’s disease, classic
neurofibromatosis, or peripheral neuro-
fibromatosis is the most common form of
• The NF1 gene responsible codes for
“neurofibromin” on chromosome 17.
• The clinical expression of NF-1 is highly
variable. Roughly, half of NF-1 cases arise via
spontaneous mutation and are not associated
with any family history.
• NF-1 is a multisystem disorder characterized
by cafe-au-lait macules (CALMs), neuro-
fibromas, Lisch nodules, optic gliomas, bony
dysplasia, intertriginous freckling and
autosomal dominant inheritance.
• Neurofibromatosis is named after
neurofibroma tumors. There are three types
of neurofibromas: cutaneous, subcutaneous
and plexiform. A single plexiform
neurofibroma or two of any type are
considered diagnostic of NF-1. Cutaneous
neurofibromas (mollusca fibrosa) are soft
lilac –pink tumors, sessile and dome shaped,
sometimes pedunculated, most numerous on
the trunk and limbs, hundreds may be
present, ranging from a few millimeters to
several centimeters in diameter. They can be
easily pushed into underlying dermal defect
with light digital pressure - “button holing”.
When pressed, the soft tumors tend to
invaginate through a small opening in the
subcutaneous tissue, giving the feeling of a
seedless raisin or a scrotum without a testicle
(Fig. 22.1). The subcutaneous type may feel
hard like a pencil eraser. They often cause
localised pain or tenderness. On the other
hand, plexiform neurofibromas are
congenital and are pathognomonic for NF-1
(Figs 22.2 and 22.3). They feel like a “bag of
worms” because of the many interdigitating
Phakomatoses or neurocutaneous syndromes are
a rare group of disorders including neuro-
fibromatosis, tuberous sclerosis, von Hippel-
Lindau syndrome, and Sturge-Weber syndrome.
Genetics and Genodermatoses 213
of cutaneous and subcutaneous types. They
present as a diffuse elongated fibroma along
the course of the nerve, frequently involving
the trigeminal or upper cervical nerves.
Neurofibromas of the female areola and
nipple are virtually pathognomonic for NF-1.
• Cafe-au-lait macules (CALMs), another
manifestation of NF-1, are discrete, well
circumscribed, round or oval, uniformly
pigmented patches (may be seen in normal
population, segmental neurofibromatosis,
Albright syndrome, ataxia telangiectasia,
Bloom’s syndrome, Watson’s syndrome,
Rubinstein-Taybi syndrome) (Figs 22.4 and
22.5). Solitary CALMs are a common finding,
affecting up to one third of normal children.
Multiple CALMs are rare, particularly in the
white population. A diagnosis of multiple
organ disorder, the most common being NF-1,
should be considered in this instance. The
minimal number of 6 lesions of CALMs was
established as a criterion for the diagnosis of
NF-1 (more than 1.5 cm in diameter in adults).
They are the first feature of the disease to
appear in all children.
• Freckling is a useful and often overlooked
sign of NF-1. Freckling involving areas of
hyperpigmentation up to 2 or 3 mm in
diameter occurs frequently in the axilla as well
as other intertriginous regions. Basically,
there are two kinds of neurofibromatosis
freckles—those that are basically very small
CALMs ordinarily present at birth or in the
Fig. 22.2: Neurofibromatosis type 1 – plexiform
neurofibromas affecting both lower limbs
Fig. 22.3: Neurofibromatosis type 1—plexiform
neurofibroma affecting foot
Fig. 22.1: Neurofibromatosis type 1 – multiple
neurofibromas over the trunk
Essentials in Dermatology214
first year of life and distributed over the entire
body and those that develop later in
intertriginous regions (Crowe’s sign) (Fig.
22.6). Multiple melanotic macules of palms
in 90% of Indian cases (Fig. 22.7). This sign
has been named as ‘Patrick Yesudian sign’
by various medical schools, in south India.
• Lisch nodulesarepigmentedirishamartomas
which appear as dome shaped lesions on the
surface of iris. They are one of the most
common manifestations of NF-1 and have
significant diagnostic value.
Fig. 22.7: Neurofibromatosis type 1—palmar
freckling “Patrick Yesudian sign”
Fig. 22.4: Neurofibromatosis type 1 – circumscribed
pigmented patch of café-au-lait macule over the trunk
Fig. 22.5: Neurofibromatosis type 1 – back
showing neurofibromas and café-au-lait macules
Fig. 22.6: Neurofibromatosis type 1—axillary
• Systemic features include:
1. Skeletal manifestations include bony
dysplasias especially tibia, pseudo-
arthrosis, cysts and scoliosis of thoracic
of children with NF-1 exhibit a learning
Genetics and Genodermatoses 215
disability, as well as attention deficit
including mental retardation occurs in
about 5%. Other features of NF-1 include
macrocephaly, short stature, and
hypertension (due to renal artery stenosis
3. Endocrine disturbances of many types
may be associated.
• Diagnosis: The spectrum of clinical findings
the seven established diagnostic criteria.
These criteria were described at a National
Institutes of Health (NIH)—sponsored
consensus conference in 1987. These were
updated in 1990. In the absence of a single
“test” that can confirm the diagnosis,
physicians often rely on these criteria. Two
criteria are required for a definitive diagnosis
and one is required for a presumptive
1. Six or more cafe-au-lait macules (CALM’s)
15 mm or more after puberty;
2. Axillary or inguinal freckling (Crowe’s
4. Two or more Lisch nodules;
5. Optic nerve glioma;
6. Characteristic skeletal dysplasias (tibial or
orbital dysplasia) and
7. Affected first degree relative.
• Three of these criteria manifest themselves on
to the skin (A single plexiform neurofibroma
or two of any type, minimal number of
6 lesions of CALMs, and axillary freckling-
• Management consists of genetic counseling,
anticipatory guidance, and surveillance for
complications. Tests such as MRI or X-rays
should be done for clinical indications only.
Children should be monitored for learning
disabilities and provided cognitive and
educational assessments as needed. Physical
examinations should include measurement of
pressure. Ophthalmologic check up is a must
in all cases. Surgery is indicated in only select
• Risk of malignancy: NF-1 is also associated
with increased risk of malignancy (malignant
peripheral nerve sheath tumors in second or
• Prognosis:Variable, dependent upon severity
of involvement and development of
malignancy. Cosmetic disfigurement is
progressive and worsens with time. Mild
course during childhood is not a guarantee
for mild disease in adulthood.
Tuberous Sclerosis (Bourneville’s
• It is now frequently designated the tuberous
sclerosis complex (TSC). It is an autosomal
dominant human genetic disease charac-
terized by widespread hamartomas, usually,
occurring in the brain, eyes, skin, kidneys,
liver, heart, and lungs.
• This disorder derives its name from a
description of its cerebral lesions by
Bourneville in 1880. Its systemic nature was
described by Vogt in the clinical triad (Epi-
loi-a) of epilepsy (seizures),low intelligence
(mental retardation) and facial lesions termed
adenoma sebaceum (a misnomer for
angiofibromas). Recent studies have shown
that full triad was evident in only about one
third of patients.
• Two third cases are sporadic and one third
are autosomal dominant.
• Two genetic loci have been identified TSC1
(Hamartin) and TSC2 (Tuberin) on
chromosome 9 and 16 respectively. These are
Essentials in Dermatology216
tumor suppressor genes, which when
deficient result in Mtor disinhibition and
abnormal proliferation of tissues resulting in
• Cutaneous features are the most frequent
finding in TSC and if overlooked, will lead to
a delay in diagnosis. Although, there is
considerable variation in the age of expression
of all the skin lesions, there is a trend towards
the earlier expression of hypomelanotic
macules and forehead plaques compared
with facial angiofibromas and ungulal
fibromas. Shagreen patches are usually
present by puberty.
• The relatively vascular and fibrous
components of adenoma sebaceum
(angiofibromas) determines their clinical
appearance (Fig. 22.8). They range from white
or flesh colored to classical red pink papules,
1-10 mm in diameter, symmetrically
distributed over the nasolabial folds, cheeks
and chin, sparing the upper lips. They are
regarded by many as a primary pathogno-
monic feature of TSC.
• Shagreen patches are not as diagnostically
useful as facial angiofibromas. They most
often appear as flat, slightly elevated areas of
the skin, soft and skin colored plaques of
variable size (1 to 10 cm) with a “pig skin”,
“elephant skin” or “orange peel appearance”.
Usually, these lesions are localized
asymmetrically over the dorsal body surfaces,
particularly over the lumbosacral area
• Periungual fibromas (Koenen’s tumors)
common in adult patients with TSC, are much
less frequent in children. They usually appear
around puberty as smooth, firm, flesh colored
excrescences and are usually 5-10 mm in
length. They are located around or under the
nail plate and arise from the bed under the
nail plate or from skin of nail groove (Fig.
22.10). Regarded as angiofibromas, they are
Fig. 22.8: Tuberous sclerosis – angiofibromas and
forehead plaque seen over the face
Fig. 22.9: Tuberous sclerosis – “orange peel
appearance” of a circumscribed area in the
lumbosacral area – Shagreen patch
classified as primary or pathognomonic
feature of TSC.
• Ash leaf macules/spots (hypomelanotic
macules) are the most frequent lesions in TSC
patients. Since, they resemble the leaf of
European mountain ash tree, they are called
as ash leaf spots. They are ovoid or leaf shaped
Genetics and Genodermatoses 217
22.8) and may be the only skin lesions in
infants and if associated with infantile
These ash leaf spots are predominantly
• Forehead fibrous plaque is classified
histologically as an angiofibroma, although
clinically it differs from the typical
papulonodular angiofibroma because of
fibromatous appearance (Fig. 22.5). It is one of
the secondary features of tuberous sclerosis.
• Molluscum fibrosum pendulum (skin tags)
are commonly seen in normal elderly people
and are uncommon in adolescents and young
adults, and should alert to the possibility of
TSC. In individuals with TSC, molluscum
fibrosum pendulum is commonly seen on the
neck, groin, axillae and near flexures of limbs,
especially in adults.
• Café-au-lait macules are not regarded as
characteristic for TSC and are not included in
the diagnostic criteria (Fig. 22.8).
• Systemic features include:
1. Neurological findings: Tuberosclerotic
nodules of glial proliferation occur in
cerebral cortex, basal ganglia, and
ventricle wall (60-70%) and are causes of
mental retardation. Once calcified, these
lesions are visible on skull radiographs as
brain stones. Epilepsy is common, usually
begins in infancy as infantile spasms or
salam attacks. Autism, attention deficit
disorder are other features.
2. Ocular: Retinal phakomas (lump of
mulberry appearance) represent proli-
feration of astrocytes. Hypopigmented
spots in iris may be seen.
3. Cardiac: Rhabdomyomas may be present
at birth and regress spontaneously in first
4. Renal: Polycystic kidney disease, isolated
renal cyst, angiomyolipomas, renal cell
5. Pulmonary: Multifocal micronodular
pneumocyte hyperplasia, pulmonary cyst,
6. Gastrointestinal: Hamartoma and
polyposis of stomach, intestine and colon.
• Investigations include:
– X-ray (skull, hands and feet, lungs);
– CT scan brain;
– MRI (brain parenchymatous lesions);
– EEG (seizures);
– Renal ultrasonogram;
– ECHO heart (rhabdomyomas);
– Neurodevelopmental testing;
– Opthalmological examination.
Diagnositic Criteria (Tuberous Sclerosis
Alliance, Consensus Conference 1998)
1. Facial angiofibromas or forehead plaque
2. Non-traumatic ungual or periungual
3. Hypomelanotic macules (more than three)
4. Shagreen patch (connective tissue nevus)
5. Multiple retinal nodular hamartomas
6. Cortical tuber
7. Subependymal nodule
8. Subependymal giant cell astrocytoma,
9. Cardiac rhabdomyoma, single or multiple
11. Renal angiomyolipoma.
Fig. 22.10: Tuberous sclerosis – periungual
fibromas, also known as Koenen’s tumors
Essentials in Dermatology218
1. Multiple randomly distributed pits in dental
2. Hamartomatous rectal polyps
3. Bone cysts
4. Cerebral white matter migration lines
5. Gingival fibromas
6. Non-renal hamartoma
7. Retinal achromic patch
8. “Confetti” skin lesions
9. Multiple renal cysts.
Definite TSC: Either 2 major features, or 1 major
feature with 2 minor features.
Possible TSC: Either 1 major feature, or 2 or more
1. Facial angiofibromas: Dermabrasion,
electrodessication, CO2, argon or pulsed
2. Seizures: For infantile spasms: ACTH/
steroids are useful. Seizures in children:
vigabatrin is the drug of choice.
• Prognosis is related to the extent of systemic
involvement. Cardiovascular complications
occur in 1st decade, brain tumor in 2nd
decade, renal and pulmonary lymphangio-
matosis in 4th decade are cause of morbidity
Von Hippel-Lindau Disease (VHL)
• VHL also referred to as CNS angiomatosis is
inherited in an autosomal dominant fashion
with incomplete penetrance with VHL gene
located on chromosome 3p25. Both sexes are
equally affected. Hippel first described retinal
angiomatosis in 1904. Lindau subsequently
recognized association with central nervous
system tumors and hence the eponym von
Hippel Lindau disease was coined.
• Cutaneous findings are portwine stains and
café-au-lait macules. Dermal capillary
malformation has predilection for the head
and neck. Other manifestations are vascular
malformations in the cerebellum and brain
stem. Retina is also commonly affected. There
may be cystic neoplasms or angiomatous
lesions in the kidneys, liver and pancreas.
• Sturge -Weber syndrome (SWS) is defined as
facial portwine stain in association with
ipsilateral plial (i.e. leptomeningeal) vascular
anomalies (with one or more symptoms;
epilepsy early in life, hemiparesis or
hemiplegia, gyriform intracranial calci-
fications and cerebral atrophy) and inconstant
ipsilateral choroidal vascular lesions with
• Portwine stain is usually unilateral, roughly
involving the areas supplied by ophthalmic
and maxillary divisions of trigeminal nerve,
and bilateral in 50% of cases.
• Portwine stains (naevus flammeus) are
congenital vascular birthmarks that are
present at birth and persist into adulthood.
At birth, they are often pale pink macular
lesions which with time, progress to become
dark red to purple (Fig. 22.11) and even
nodular. These changes occur as a result of
progressive ectasia of cutaneous superficial
• Portwine stains can either occur as isolated
cutaneous or be associated with structural
abnormalities especially of those underlying
the birth mark such as the choroidal vessels
in the eye which produce glaucoma and
leptomeningeal vessels in the brain which
causes seizures, then is known as SWS.
Genetics and Genodermatoses 219
Fig. 22.11: Sturge Weber syndrome—port wine nevus
seen along ophthalmic and maxillary division of
(Pigmented Dry Skin)
by photosensitivity, pigmentary changes,
premature skin aging, neoplasia and abnormal
• Eight different subtypes – complementation
groups A to G and XP variants.
• Main defect is in the DNA excision repair
process (this is a process whereby damaged
DNA is replaced with new DNA).
• XP- variants have a normal nucleotide
excision repair but the defect here is of a
reduced molecular weight of newly
synthesized DNA in UV radiated cells.
• Skin normal at birth.
• Earliest symptoms of dryness and freckling
appear between six months and three years of
• Freckles appear over face and hands, and later
on neck, legs, lips and conjunctiva. Eventually
freckles become permanent and progressively
increase in number.
• Continued sun exposure causes skin to
become dry and parchment-like with
pigmentation (hence the name xeroderma
• Next is the poikilodermatous stage
characterized with atrophy and telangiectasia
superadded to the existing freckles and
hyperpigmentation (Fig. 22.12).
• Superficial ulcers and atrophy may leave scars
• Ocular features include – photophobia with
conjunctival injection, symblepharon,
ectropion / entropion and loss of eye lashes
due to atrophy of eyelid skin, keratitis leading
to corneal opacity, pterygium and ocular
Fig. 22.12: Xeroderma pigmentosum—freckle like
pigmentation with atrophy, telangiectasia and actinic
Essentials in Dermatology220
Fig. 22.13: Xeroderma pigmentosum—freckle like
pigmentation with fungating squamous cell tumor of
the face and scalp
• Pre-malignant lesions like actinic keratosis
and keratoacanthomas may occur in most
• Patients with XP under 20 years of age have
a greater than 1000-fold increased risk of
cutaneous basal cell or squamous cell
carcinoma or melanoma (Fig. 22.13). The
median age of onset of nonmelanoma skin
cancer reported in patients with XP is
• Overall, there is a ten to twenty-fold increase
lung, gastric, breast, renal, etc.) in XP.
• 20% have neurological complaints – mental
retardation, areflexia, spasticity, ataxia, and
• Disease is often fatal under 10 years of age
and two thirds of the cases die by 20 years of
• De Sanctis –Cacchione syndrome consists of
xeroderma pigmentosum, with microcephaly,
mental deficiency, dwarfism, hypogonadism,
choreoathetosis, and ataxia.
• Prenatal diagnosis by amniocentesis is
• Differential diagnosis includes ordinary
freckling, other causes of photosensitivity and
premature ageing syndromes such as
Rothmund-Thomson syndrome, Bloom
• Treatment: The mainstay of management is
by ensuring maximum photoprotection
filter glasses). Ocular symptoms should be
managed promptly to prevent complications.
Early and adequate excision of all tumors is
essential and topical 5-fluorouracil may be
used for pre-malignant lesions. Oral retinoids
have been found to decrease the occurrence of
skin cancers in this condition.
• Incontinentia pigmenti is an uncommon
genodermatosis of the developing
neuroectoderm in which vesicular, verrucous
and pigmented lesions are associated with
developmental defects of eye, skeletal
system and central nervous system.
• Incontinentia pigmenti is a complex
hereditary syndrome that principally affects
female infants. It is inherited as an X-linked
dominant disorder, caused by mutation of
NEMO gene on chromosome Xq28. The gene
is generally lethal in male fetuses.
• This multisystem disorder has manifestations
of dermatological, neurological, skeletal,
ocular or dental origin.
• It manifests at birth or during first weeks of
• In the skin, the disorder characteristically
progresses through four stages. The first stage
Genetics and Genodermatoses 221
Fig. 22.14: Incontinentia pigmenti – linear whorled
vesicular eruption along Blashko’s lines over the
(vesicular phase) is characterized by linear
whorled vesicular eruption along Blaschko’s
lines (Fig. 22.14). The eruption typically favors
acral locations. Peripheral leucocytosis and
eosinophilia may occur during this stage. This
stage is followed 2 to 6 weeks later by
verrucous or lichenoid lesions on the sites of
the former vesicular eruption in 30% of
patients. The third stage (pigmentary phase)
starts between 12th and 20th week and is
characterized by hyperpigmented lesions. A
fourth stage, rarely seen in some adult females
is characterized by faint hypochromic or
atrophic linear macules over extremities. The
hair is usually normal, but in 25% of cases,
cicatricial alopecia may be seen.
• Incontinentia pigmenti achromians
(hypomelanosis of Ito) suggest the negative
image of incontinentia pigmenti characterized
by unilateral or bilateral hypopigmentation
along the lines of Blaschko.
• Usually, no treatment is necessary other than
the control of secondary infection.
Essentials in Dermatology222
SKIN IN ENDOCRINE DISORDERS
Hormones secreted by endocrine glands have
physiological effects on pigmentation, hair
growth, sebaceous glands and connective tissue.
Endocrine disorders are associated with various
cutaneous manifestations which offer clue to the
diagnosis of the underlying endocrine disorder.
SKIN IN PITUITARY DISORDERS
Acromegaly: It results from excessive secretion
of growth hormone by pituitary adenomas (98%
of cases) in adolescents or adults. Patients are
tall and have prognathism, frontal bossing,
elongated, blunt and thickened fingers.
Dermatological features include thickening of
skin, accentuation of facial, neck and scalp
creases imparting corrugated appearance (cutis
verticis gyrata), widened triangular shaped nose,
large ears, large and protruding lower lip,
edematous thick eyelids, macroglossia,
numerous skin tags (fibroma molluscum),
seborrhea, acne, hyperhidrosis,
hyperpigmentation, acanthosis nigricans, coarse
scalp and body hair, wide and thickened nails.
Panhypopituitarism: It results from destruction
of pituitary gland from various causes (post
partum hemorrhage “Sheehan’s syndrome”,
adenoma, craniopharyngioma, tuberculosis,
Skin in Systemic Diseases
sarcoidosis, or iatrogenic) leading to multiple
hormone deficiency. Cutaneous manifestations
are non-specific and include xerotic skin, fine
wrinkling around eyes and mouth, pallor,
generalized hypopigmentation, increased sun-
burn tendency, thinning of scalp and body hair,
reduced sweat and sebaceous gland activity and
thin brittle nails.
SKIN IN ADRENAL SYNDROMES
Cushing’s syndrome and Cushing’s disease:
Cushing’s disease refers to hypercortisolism
(glucocorticoid excess) from ACTH over-
production, most commonly by pituitary
adenoma, whereas Cushing’s syndrome refers
to hypercortisolism, resulting from any cause,
such as pituitary ACTH overproduction, ectopic
ACTH production, or from adrenal adenoma,
carcinoma or hyperplasia, or from glucocorticoid
therapy. Skin is atrophic, smooth and
transparent (paper thin), and there is facial
fullness and plethora (moon facies), buffalo
hump (Fig. 23.1), fullness of supraclavicular
fossa, truncal obesity and relative lack of fat in
lower extremities “lemon on stick appearance”,
poor wound healing, striae particularly over
abdomen, arms, and thighs, purpura, petechiae,
easy bruising and purplish mottling (cutis
marmorata), acneiform eruptions, hirsutism,
Skin in Systemic Diseases 223
male pattern baldness in females, addisonian like
pigmentation, and increased incidence of fungal
Addison’s disease (primary adrenal insuffi-
ciency): It refers to insufficient secretion of
adrenocortical hormones mainly cortisol and
mineralocorticoids due to destruction of adrenal
glands. Various causes of adrenal gland damage
are autoimmune disorders in 70% of cases,
tuberculosis, fungal infections, sarcoidosis,
metastasis, and hemorrhage. Secondary adrenal
insufficiency results from hypothalamic or
pituitary diseases leading to decreased ACTH
secretion, or steroid withdrawal after long term
General features of Addison’s disease are
fatigue, dizziness, anorexia, nausea, vomiting,
diarrhea, abdominal pain and hypotension.
Cutaneous findings are hyperpigmentation of
skin due to elevated ACTH and MSH, mainly
over light exposed areas, elbow, knee, knuckles,
axillae, areolae, umbilicus, genitalia, palmar
creases (Fig. 23.2), tongue and mucous
membranes, scars, and nails. Fibrosis and
calcification of ear may occur. Hyper-
pigmentation is absent in secondary adrenal
insufficiency (referred to as “white Addison’s
Pheochromocytoma: It is a rare adrenal tumor
(mostly benign). Main clinical feature is
hypertension, but can lead to flushing episodes.
SKIN IN THYROID DISEASES
It may be a manifestation of Grave’s disease
(most common cause), toxic multinodular goiter,
adenoma, Hashimoto’s thyroiditis (early stage)
Grave’s disease: It is an autoimmune disease
characterized by antithyroid antibodies such as
long acting thyroid stimulator (LATS). Skin is
warm, moist and smooth, and there is facial
flushing, palmar erythema, generalized
hyperhidrosis more so on palms and soles,
pruritis, urticaria, addisonian hyperpigmen-
tation, hyperpigmentation of eyelid (Jellinek’s
sign), and thyroid swelling in the neck. Scalp hair
become fine, soft and friable, telogen effluvium
can occur. Nails grow rapidly, become thin and
soft, develop distal onycholysis (Plummer’s
In addition to these features of hyper-
thyroidism, patients of Grave’s disease may have
pretibial myxoedema, thyroid acropachy and
exophthalmos (Diamond’s triad).
Fig. 23.1: Cushing’s syndrome—buffalo hump Fig. 23.2: Addison’s disease—hyperpigmentation of
Essentials in Dermatology224
Pretibial myxoedema is characterized by
bilateral asymmetric, firm, hyperpigmented,
plaques or nodules, with orange peel texture
(peau d’orange) mainly over shins and feet due
to cutaneous accumulations of glycosamino-
glycans (Fig. 23.3). Localized hypertrichosis and
hyperhidrosis can occur over these lesions .
Thyroid acropachy is characterized by digital
clubbing, soft tissue swelling of hands and feet,
and diaphyseal proliferation of periosteum in
acral and distal long bones (tibia, fibula, ulna and
Exophthalmosis due to orbital deposits in orbital
fossa, always bilateral. Autoimmune diseases
such as vitiligo, alopecia areata can occur in
association with Grave’s disease.
Deficiency of thyroid hormone may be caused
by Hashimoto’s thyroiditis, iodine deficiency,
iatrogenic following total thyroidectomy,
radioiodine therapy, drugs such as lithium,
congenital hypothyroidism and secondary
hypothyroidism due to reduced TSH from
pituitary. The dermal manifestations are mainly
due to accumulation of mucopolysaccharides
(chondroitin sulphate and hyaluronic acid) in the
skin. Skin appears rough, cool, dry, swollen,
waxy and pale with increased skin creases, and
there can be reduced sweating, asteatotic
eczema, pruritis, and palmoplantar keratoderma
(palms and soles, yellow-orange due to
carotenemia). Patient may have characteristic
expressionless facies with puffy and drooping
eyelids, broad nose, swollen lips, and
macroglossia. There is delayed wound healing,
purpura, ecchymosis and xanthomatosis may
Nails grow slowly, become thick and brittle
with longitudinal and transverse striations. Scalp
and body hairs are sparse, coarse, dry and brittle,
tend to fall out easily resulting in diffuse or
partial alopecia. Loss of lateral third of eyebrows
(madarosis) -Hertoghe’s sign
In juvenile hypothyroids, waxy yellowish
skin change is more prominent, but puffiness
may be less apparent.
In cretinism, infants will have periorbital
puffiness, macroglossia, swollen hands and feet,
cold and dry skin, cutis marmorata and umbilical
hernia (pathognomonic). Unlike in adult
hypothyroid, eyebrows tend to be confluent.
SKIN IN PARATHYROID DISEASES
Primarily occurs due to adenoma, hyperplasia
or carcinoma of parathyroid glands and
secondary due to chronic renal failure.
Subcutaneous calcifications can present as
linearly arranged white papules or as infiltrating
plaques usually over large joints. Subcutaneous
calcification and calciphylaxis mainly occur in
Fig. 23.3: Pretibial myxoedema—bilateral firm hyper-
pigmented plaques with orange peel texture over shins
Skin in Systemic Diseases 225
Congenital absence of glands (Di George’s
syndrome), thyroid surgery, hemochromatosis,
metastatic cancer, or idiopathic in origin may be
its causes. Skin changes may be similar to that
of hypothyroidism. The skin becomes dry,
hyperkeratotic and puffy with sparse and coarse
hair. Chloasma and pellagra like pigmentary
changes can occur. Nails become opaque and
brittle with transverse ridges. Impetigo
herpetiformis, psoriatic flares and eczematous
dermatitis have been associated with
hypoparathyroidism. Normalization of serum
calcium levels with calcium and vitamin D
usually reverse skin abnormalities.
SKIN IN DIABETES MELLITUS
Diabetes mellitus (DM) is characterized by
relative or absolute deficiency of insulin, leading
to gross defects in glucose, fat and protein
Type I DM (Insulin dependant DM) is due to
insulin insufficiency from antibody
mediated destruction of beta cells of
Type II (Non-insulin dependant DM) results
from hyperglycemia mainly due to
peripheral insulin resistance.
Nearly all patients with DM have some skin
manifestations. For most manifestations the
pathogenesis remains unknown, and others
result from damage to vascular, neurologic or
immune systems. Macro and microangiopathy
contribute significantly to the cutaneous
complications of DM.
Cutaneous Manifestations of DM
1. Skin Infections
DM patients are at higher risk of contracting
bacterial and fungal infections when compared
to normal population. Staphylococcal and
streptococcal pyodermas (folliculitis, furuncle,
carbuncle), malignant otitis externa (caused by
Pseudomonas aeruginosa), necrotizing fasciitis, and
clostridial gangrene occur more frequently in
diabetics. Candida albicans is the most common
pathogen, causing intertrigo, vulvovaginitis,
balanitis, glossitis, angular cheilitis, paronychia
and onychomycosis. Tinea pedis and onycho-
mycosis of toe nails are common. Rhinocerebral
mucormycosis, a fatal condition caused by
mucor and rhizopus species occur more
commonly in diabetics.
2. Markers of DM
Acanthosis nigricans (AN) presents as brown
to gray black papillomatous cutaneous
thickening of the flexural areas including
posterolateral neck (most common site), axillae,
groin and abdominal folds. Affected area will
have velvety appearance, and it may involve
mucous membranes also. AN can also occur in
association with obesity, internal malignancy
and with drugs such as corticosteroids and
Fig. 23.4: Diabetes mellitus—generalized
Essentials in Dermatology226
Generalized granuloma annulare presents with
numerous small annular plaques formed by 1-2
mm flesh colored papules (Fig. 23.4). These
lesions are symmetric and appear more
commonly over the abdomen, chest, thighs and
extensor of elbows, most frequently in older
Necrobiosis lipoidica (NL) is a cutaneous
disorder, often but not always associated with
diabetes mellitus. Sixty to seventy percent of
patients have DM, so patients presenting with
NL should be investigated for DM. More
commonly affects middle aged women. The skin
lesions start as skin colored or brownish red
papule which evolve slowly into well
demarcated waxy plaque of variable size. They
have sharply defined, broad violet red or pink,
elevated border and depressed yellow-orange
centre with telangiectasias. Ulcerations
commonly occur within the plaques and heal
slowly resulting in depressed scars. Almost
always affects shins, but can involve thighs,
trunk, and face, scalp (scarring alopecia). Rarely
disseminated NL can occur called as
granulomatous disciformis chronica and
Bullosis diabeticorum is characterized by
abrupt onset of bullae, mainly over the lower
legs, feet, toes, and occasionally over dorsa of
hands and fingers. Bullae appear over non
inflamed skin, and measured from few
millimeter to 3-5 cm in size, non-pruritic and
painless. Healing occurs within 2 to 5 weeks and
rarely leaves scar. Pathogenesis of bulla
formation is unknown. Increased skin fragility
due to glycosylation end products may be
Scleredema diabeticorum is characterized by
insidious onset of painless, symmetric induration
of skin and subcutaneous tissue mainly over
upper back, neck, and rarely face, shoulder and
anterior torso. Skin has non pitting, woody,
“peau d’ orange” quality. There is decreased
sensation to pain and light touch over the
affected area, and decreased range of
movements in neck and upper extremities. Most
patients have type II diabetes. It is due to
thickening of collagen bundles and deposition
of glycosaminoglycans (mainly hyaluronic acid).
3. Complications of Diabetes
Atherosclerosis induced by DM can lead to
ischemic gangrenous changes in legs and feet,
hypothermia, dry skin and nail dystrophy.
Microangiopathy causes many cutaneous
manifestations, which include:
1. Wet gangrene of foot–occurs as a late
2. Erysipelas like erythema–well demarcated,
red areas occur on the legs or feet usually in
3. Diabetic rubeosis-peculiar rosy reddening of
the face, rarely of hands and feet in long
4. Diabetic dermopathy (diabetic shin spots or
Binkley spots)— Most common dermatosis
associated with diabetes. They start as crops
of asymptomatic, oval, dull red papules
0.5-1cm in diameter, which gradually evolve
into atrophic hyperpigmented lesions mainly
over shins, also over forearms, thighs and
bony prominences. If 4 or more are present,
the specificity is high for microvascular
disease in other tissues. An association seems
to exist between dermopathy and other
serious complications such as retinopathy,
nephropathy and neuropathy.
Diabetic Neuropathy And Diabetic Foot
Diabetic foot is mainly caused by peripheral
neuropathy but micro and macroangiopathy and
infections also contribute. Diabetic neuropathy
Skin in Systemic Diseases 227
is usually distal, polyneuritic, sensory and motor
neuropathy. Motor neuropathy causes weakness
and wasting of muscles, thereby uneven pressure
on feet while walking. Sensory neuropathy
predisposes to trauma and autonomic
involvement causes hypohidrosis. All these
factors combine to produce neurotrophic ulcers
mainly over bony prominences; most commonly
over the ball of great toe. The ulcer is usually
painless, circular and punched out surrounded
by a ring of callus. Some patients present with
burning sensation in the feet.
4. Skin Diseases Commonly Associated with
Eruptive xanthomas, skin tags, vitiligo, lichen
planus, acquired perforating disorders such as
Kyrle’s disease, reactive perforating collagenosis,
uremic pruritis occur commonly in association
5. Complications of Diabetic Therapy
Oral hypoglycemic agents may produce allergic
reactions, and photosensivity. Insulin causes
erythema, urticaria and lipodystrophy at
SKIN IN PRIMARY SYSTEMIC
Primary systemic amyloidosis involves
mesenchymal tissue, the tongue, heart,
gastrointestinal tract and skin. Cutaneous
manifestations occur in approximately 40% of
cases of primary systemic amyloidosis. The
cutaneous eruptions usually begin as shiny,
smooth, firm, flat topped or spherical papules
of waxy color and have the appearance of
transluscent vesicles because of their tenseness.
These lesions coalesce to form nodules and
plaques of various sizes. The regions about the
eyes, nose, mouth and mucocutaneous junctions
are commonly involved. Purpuric lesions and
ecchymoses resultant of infiltration of blood
vessels, chiefly affect the eyelids, limbs and oral
cavity. Purpura typically occurs after trauma
(pinch purpura). Purpuric lesions also classically
appear after actions or procedures that result in
increased pressure in the vessels of the face such
as after proctoscopic examination. Glossitis with
macroglossia may be an early symptom and can
lead to dysphagia. The tongue becomes greatly
enlarged and furrows develop. The lateral
aspects show indentations from the teeth
(Fig. 23.5). Diagnosis is confirmed by evaluation
of patient’s serum and urine for immunoglobulin
fragments and by demonstration of amyloid
deposits in the skin.
SKIN IN VASCULITIS
The term vasculitis refers to inflammation and
necrosis of blood vessels. The vasculitides are
best classified according to the size of the
involved vessels into large, medium and small
Classification of the Vasculitides
A. Large Vessel Vasculitis
1. Giant cell arteritis
2. Takayasu arteritis
Fig. 23.5: Systemic amyloidosis—macroglossia
showing indentations of the tongue with gum
Essentials in Dermatology228
B. Medium-sized Vessel Vasculitis
1. Kawasaki disease
2. Polyarterites nodosa (PAN)
3. Benign cutaneous PAN
C. Small Vessel Vasculitis
1. Henoch-Schönlein purpura
2. Cutaneous leukocytoclastic angiitis
3. Microscopic polyangiitis
4. Wegener’s granulomatosis
5. Churg – Strauss syndrome
Blood vessels have limited ways of
responding to vessel wall injury. They may
respond with increased permeability that leads
to edema and purpura, attenuation of the vessel
wall lead to aneurysm formation or hemorrhage,
and intimal proliferation or thrombosis may
cause stenosis or occlusion with tissue ischemia
or infarction. The definitive diagnosis of a
specific “vasculitis” remains dependent upon
histopathologic confirmation of vasculitis in
conjunction with the appropriate clinical picture
and the exclusion of diseases that can cause
secondary vascular inflammation such as
infection (e.g., meningococcemia, gonococcemia,
and endocarditis). The principal clinical clue to
diagnosis of a specific vasculitic disorder is the
pattern of organ involvement. Identification of
qualitative pathologic changes in affected organs
(pattern of necrosis, presence of granulomas,
eosinophilic infiltration) further delineates the
The identification of a vasculitic disorder may
not always be easy because of the varied clinical
presentations. More than one system is often
involved and the manifestations can, therefore,
be very heterogenous. However, there are some
clinical pointers that may suggest the presence
of a vasculitic disorder. These are-
1. Prolonged fever of unknown origin.
2. Suggestive skin lesions e.g. palpable purpura
(Fig. 23.6), gangrene.
3. Unexplained peripheral neuropathy
especially mononeuritis multiplex.
4. Arthralgia/arthritis, myositis, serositis.
5. Obscure pulmonary, cardiovascular or renal
disease especially when there is multi-system
6. Laboratory parameters indicative of ongoing
inflammation: e.g. leukocytosis, elevated
ESR/CRP, eosinophilia, hypocomplemen-
temia, cryoglobulinemia, circulating immune
Kawasaki disease and Henöch-Schonlein
purpura are the commonest vasculitides seen in
children while giant cell arteritis, polyarteritis
nodosa and Wegener’s granulomatosis are more
common in the adults.
Giant Cell Arteritis (GCA)
GCA generally affects individuals older than
50 years of age and is variably associated with
fever, headache, masticatory muscle
claudication, peripheral vascular disease,
inflammatory aortic aneurysms, and retinal
Fig. 23.6: Vasculitis—palpable purpuric lesions
over the legs of hypersensitivity vasculitis
Skin in Systemic Diseases 229
ischemic syndromes. Cutaneous manifestations
include rare cases of scalp or tongue ischemia
and necrosis. The diagnosis is established by
biopsy of the superficial temporal artery, which
shows chronic mononuclear cell infiltrate, and
Takayasu Arteritis (TA)
TA is a chronic, idiopathic inflammatory disease
primarily affecting the large vessels, such as the
aorta and its branches. It is also known as
‘pulseless disease’ and ‘reverse coarctation’. TA
is more commonly associated with aortic and
aortic branch vessel stenoses and aneurysms
TA is the most common cause of giant cell
arteritis in young patients. It mainly affects
females in the age group of 10-30 years. The
precise etiology of TA is still unknown. The most
common complaints at the onset of the disease
include headache, dyspnea, palpitations,
arthralgia/ arthritis and myalgia. Constitutional
features can be in the form of fever, night sweats,
weight loss and anorexia which may be seen in
>50% of patients. The onset of hypertension and/
or absence of upper limb pulses are often the
complaints, which lead to a correct diagnosis.
Polyarteritis Nodosa (PAN)
This is rare in childhood, commonly occurs in
adults. Clinical presentation of PAN is extremely
variable. The initial symptoms can be rather
vague and ill defined with fever, malaise and
weight loss being prominent complaints.
Hypertension is present in more than
80% of patients and the ESR is usually elevated.
CNS involvement occurs in 50 to 70% of children
and may first bring the patient to the attention
of the physician. The other features that suggest
the possibility of PAN are the presence of a
typical livedo reticularis rash, abdominal pain,
arthritis, myalgia and peripheral gangrene.
Kawasaki Disease (KD)
KD is an acute systemic vasculitis of infancy and
childhood. This clinical entity is also known as
mucocutaneous lymph node syndrome. The
clinical diagnosis of KD is usually quite
straightforward, provided one keeps it in mind,
whenever one encounters a young child with a
febrile illness for which no other cause can be
found. KD is a syndrome in which there is a
constellation of clinical findings, which appear
sequentially, with none of the features taken
individually being of any significance.
Diagnostic Criteria for Kawasaki Disease
1. Fever lasting for at least 5 days.
2. Presence of four of the following five
i. Bilateral conjunctival injection
ii. Changes of the mucosae of the oropharynx,
including injected and/or fissured lips,
iii. Changes of the peripheral extremities such
as edema and/or erythema of hands and/
or feet, desquamation usually beginning
iv. Rash, primarily truncal; polymorphous but
v. Cervical lymphadenopathy
3. Illness not explained by other known disease
Henoch-Schönlein Purpura (HSP)
HSP is one of the most common vasculitides of
childhood. HSP is a clinical diagnosis and is
characterized by the presence of non-
thrombocytopenic palpable purpura, arthralgia
or arthritis, abdominal pain and gastrointestinal
hemorrhage. These symptoms may occur over
days to weeks. HSP is usually associated with
vascular and renal deposition of IgA-containing
Essentials in Dermatology230
Cutaneous Leukocytoclastic Vasculitis
(Hypersensitivity Vasculitis, Small Vessel
This is the most common form of vasculitis that
exclusively affects capillaries and venules,
almost invariably involves the skin. It is
frequently associated with immune complex
deposition (with underlying infections, drugs,
malignancy, collagen vascular disorders, etc).
This form of vasculitis has also been termed as
hypersensitivity vasculitis. This small vessel
vasculitis may be limited to the skin or may be
associated with visceral involvement including
pulmonary hemorrhage, intestinal ischemia or
hemorrhage, and glomerulonephritis.
Common manifestations include purpura
and/or urticaria, abdominal pain, gastro-
intestinal bleeding or intussusception,
arthralgias, arthritis or periarthritis, and
glomerulonephritis. Visceral symptoms may
precede the skin lesions, leading to diagnostic
confusion. Purpura tends to occur in crops of
lesions of similar age. Palpable purpuric lesions
are generally more pronounced in gravity-
dependent areas like legs (Fig. 23.6). Papules,
urticaria/angioedema, pustules, vesicles, ulcers,
necrosis, and livedo reticularis may be seen.
Paraneoplastic vasculitis is a term used to
describe cutaneous necrotizing vasculitis with
associated malignant conditions, including
Hodgkin’s disease, lymphosarcoma, adult T cell
leukemia, mycosis fungoides, myelofibrosis,
acute and chronic myelogenous forms of
leukemia, IgA myeloma, diffuse large cell
leukemia, hairy cell leukemia, squamous cell
bronchogenic carcinoma, prostatic carcinoma,
renal carcinoma, and colon carcinoma.
Urticarial vasculitis represents a peculiar subset
of small vessel vasculitis, characterized by typical
wheals or serpentine papules formation,
sometimes with angioedema. Individual lesions
are slower to resolve than typical urticaria and
often last for several days. There is frequently a
burning sensation or discomfort from the lesions.
These lesions often heal with skin discolor-
ation—hyperpigmentation or an ecchymotic
area. Most cases of urticarial vasculitis are
idiopathic; they may be associated with an
underlying autoimmune disorder such as SLE
or Sjögren’s syndrome, IgM paraproteinemia
(Schnitzler’s syndrome), viral infections
(hepatitis, acute Epstein-Barr), and Henoch-
Microscopic polyangiitis (MPA) involves vessels
ranging in size from capillaries and venules to
medium-sized arteries. Glomerulonephritis,
especially rapidly progressive glomerulone-
phritis, and alveolar hemorrhage are particularly
common in MPA and uncommon in PAN.
Antibody to myeloperoxidase, a type of P-
ANCA, is detected in sera from 60 percent of
patients with MPA.
Benign Cutaneous PAN (BC PAN)
BC PAN is a rare vasculitic entity mostly seen in
adults. The appearance of painful, violaceous,
palpable nodules or ridges of variable size along
the course of arterioles characterize this relatively
benign condition. Mild constitutional symptoms
and arthritis of the weight bearing joints may
occur. The exact etiology of this condition is not
Wegener’s Granulomatosis (WG)
WG is a potentially lethal, necrotizing,
granulomatous angiitis affecting small and
medium sized vessels with a predilection for the
sinuses, nasal passages, pharynx, lungs and
kidneys. In some instances, the lesions may be
widely scattered and may involve the skin, heart,
CNS, GI tract and joints. Constitutional
symptoms such as fever and weight loss are
usually quite prominent.
Skin in Systemic Diseases 231
Churg-Strauss Syndrome (CSS)
(Allergic Angiitis and Granulomatosis)
CSS, like WG, affects small- to medium-sized
arteries and veins. Clinically, CSS and WG have
similar patterns of organ involvement and
pathology, especially in regard to upper and
lower respiratory system disease and glomer-
ulonephritis. CSS differs most strikingly from
WG by its usual occurrence in patients with a
history of atopy, asthma, or allergic rhinitis,
which is often ongoing. In the prevasculitic atopy
phase, as well as during the systemic phase of
the illness, eosinophilia is characteristic and often
of striking degree. Systemic features of CSS
include some combination of pulmonary
infiltrates, cardiomyopathy, coronary arteritis,
pericarditis, polyneuropathy (symmetric or
mononeuritis multiplex), ischemic bowel
disease, eosinophilic gastroenteritis, ocular
inflammation, nasal perforations, glomeru-
lonephritis, and cutaneous nodules and/or
Early diagnosis and prompt treatment (with
corticosteroids or immunosuppressive drugs)
can go a long way in decreasing the morbidity
and mortality associated with these disorders.
METASTATIC DEPOSITS OF
Five to ten percent of patients with cancer
develop skin metastases. Usually metastases
occur as numerous firm, hard or rubbery masses
with predilection for the chest, abdomen, or
scalp, in an adult over the age of 40 years who
has had a previously diagnosed carcinoma. They
are most commonly intradermal papules,
nodules or tumors that are firm, skin colored to
reddish, purplish, black or brown. Inflammatory
carcinoma (carcinoma erysipeloides) is
characterized by erythema, edema, warmth and
a well defined leading edge similar to erysipelas
in appearance. This is usually caused by breast
carcinoma. The so-called Sister Mary Joseph
nodule (Fig. 23.7) is formed by localization of
metastatic tumors to the umbilicus. The most
common primary sites are the stomach, large
bowel, ovary and pancreas. Dissemination to the
skin is often a late finding and metastases to other
organs have usually occurred. A poor prognosis
is thus the rule.
Most cases of Hodgkin’s disease of the skin
usually originate in the lymph nodes from which
the extension to the skin is either retrograde
through the lymphatics or by direct extension.
Lesions present as papules or nodules with or
without ulceration. Cutaneous B-cell lymphoma
may present with solitary or multiple papules,
plaques or nodules (Figs 23.8 and 23.9). The most
common morphology of leukemic infiltration of
the skin in all forms of leukemia is multiple
papules or nodules or infiltrated plaques. They
are rubbery on palpation and ulceration is