introduction of dermatovenerology for medicine students

1. INTRODUCTION
TO
DERMATOLOGY
Assistant Dr. Miloš Divjak
University of East Sarajevo
Medical Faculty Foča
div_milos@yahoo.com

2. Recommended literature:
• Lookingbill and Marks' Principles of Dermatology 6th
Edition
• Fitzpatrick's Color Atlas and Synopsis of Clinical
Dermatology, 8e
• Rook's Dermatology Handbook 2022.

3. GRADING POLICY POINTS PERCENTAGE
Pre-exam activities
lecture/exercise attendance 20 20%
colloquium 30 30%
%
Final exam
practical exam 20 20%
written test 30 30%
TOTAL 100 100%

4. Objectives of the course
• To know the normal skin structure.
• To be able to take proper history.
• To be able to describe lesions by using proper
dermatological terminology.
• To be able to formulate a differential diagnosis.
• To be able to diagnose and treat common skin
disorders.
• To be familiar with dermatologic emergencies .

5. Lecture outlines
•Function , Structure of the skin.
•Approach to dermatology patient.
•Descriptive Terms and morphology
of skin lesions.
•Important signs and Investigations.
•Topical therapy.

6. Introduction to dermatology
• The skin is a complex,
dynamic organ.
• It is the largest organ
of the body.

7. • The skin covers the entire surface of the body and is its
largest organ.
• In an adult, it has a surface area of 1.2-2.2m2 and,
depending on the habitus, participates with 8-20% in the
total body mass.
• The thickness of the skin is not the same on all parts of
the body and varies from 0.5-4.0 mm.
• It is thinnest on the tympanic membrane, thicker on the
extensor sides of the limbs compared to the flexor ones,
and the thickest on the soles of the feet.

8. The surface of the skin is not smooth, but uneven and
has large and small folds and furrows.

9. Function
• Barrier to harmful exogenous substance &
pathogens.
• Prevents loss of water & proteins.
• Sensory organ protects against physical injury.
• Regulates body temperature.
• Important component of immune system.
• Vit .D production by absorbing UVB.
• Has psychological and cosmetic importance
such as hair, nails.

10. • The skin has a very complex and highly specialized structure
consisting of 3 layers:
• epidermis, of ectodermal origin, made up of cells,
• dermis, of mesodermal origin, is predominantly a connective
tissue structure,
• hypodermis, of mesodermal origin, consists mainly of a variable
amount of fat tissue (panniculus adiposus) which does not strictly
belong to the skin.

11. • The boundary between the epidermis and the dermis is not straight,
but wavy due to the existence of epidermal extensions that descend
into the dermis.
• Between them there are dermal ridges - dermal papillae.
• The border between the dermis and the hypodermis is generally flat
and not as sharply demarcated as between the epidermis and the
dermis.

12. Histology Skin Structure
The skin consists of:
• Epidermis
• Basement membrane
• Dermis
• Subcutaneous tissue
• Skin appendages

13. Epidermis
• "epi" coming from the Greek meaning "over"
or "upon”
• Is the outermost layer of the skin.
• The main type of cells are:
 Keratinocytes
 Melanocytes
 Merkel cells
 Langerhans cells

14. Epidermis
• This epithelium is continuously renewed by the proliferation of cells of
the basal layer (keratinization process), while the dead cells fall off the
surface.
• During the process of keratinization and movement to the surface,
epithelial cells change shape and phenotypic characteristics.
• Keratinocytes are the basic cells of the epidermis and make up over 80%
of the cellular composition of this layer of skin. Their main task is the
creation of keratin.
• In addition to keratinocytes, the epidermis also contains pigment cells -
melanocytes, Langerhans cells that play a role in immune defense, and
Merkel cells with a mechanoreceptor role.
• There are also free nerve endings in the epidermis.

15. Skin Structure
Epidermis: Consist of several
zones
• Basal layer (stratum basale):
columnar dividing cells.
• Spinous layer (stratum
spinosum): polyhedral cells
attached by desmosomes.
• Granular layer (stratum
granulosum): flat cells
containing keratohyaline
granules.
• bright layer;
• Cornified layer (stratum
corneum ): dead cell with no
organells.

16. Stratum basale s. stratum
germinativum (basal layer)
• The basal layer is the basic and at the same time the
deepest layer of the epidermis, which contains one
row of palisade-arranged mitotically active cells -
keratinocytes, from which other keratinocytes are
formed.
• Cells are attached to the basement membrane by
hemidesmosomes, while they are connected to each
other by desmosomes.
• Functionally, the basal layer is characterized by
pronounced mitotic activity.
• The cells of the stratum basale are the germinal cells
from which all other layers of the epidermis arise
(epidermopoiesis).

17. Stratum spinosum s. stratum Malpighii (spinous layer)
• Spinous layer consists of 5-10 rows of
keratinocytes whose appearance varies
depending on the position, i.e. the cells of the
more superficial layers become more and
more flat compared to those lying
immediately above the basal layer.

18. Histology Skin Structure
Spinous cell layer
(stratum spinosum):
• Adhere to each other by
Desmosomes (complex
modification of the cell
membrane).
• Desmosomes appear like
spines hence the designation
Stratum Spinosum.
• Langerhan cells are antigen
presenting present in
abundance .

19. Stratum granulosum (granular layer)
• Granular layer contains 2-4 rows of
flattened cells whose longer axis is
parallel to the basement membrane.
• Keratinocytes of this layer are dominated by
keratohyaline granules that can be seen using a light
microscope.

20. Histology Skin Structure
•
Granular cell layer (stratum
granulosum):
• Diamond shaped cells.
• Cytoplasm is filled with
Keratohyaline granules.
• Thickness of this layer is
proportional to the thickness
of the stratum cornium layer .
• In thin skin it is 1 -3- cell
layers and 10 cell layers in
thick skin.

21. Stratum lucidum (bright layer)
• Light layer is quite thin and elastic. In places where
the skin is tender and thin, this layer contains a
single row of cells.
• On the palms and soles, where the stratum
corneum is wide, a light layer is developed and
contains 2-3 rows of cells that are flat, elongated,
horizontally placed and filled with eleidin that is
dissolved in keratohyalin.
• On the histological preparation, this layer has the
appearance of a homogeneous eosinophilic stripe
located between the granulosa layer and the
stratum corneum.
• The boundaries between the cells are not visible, so
there are opinions that the stratum lucidum
represents only the deepest part of the stratum
corneum.

22. Stratum corneum (hotny layer)
• Stratum corneum is composed of about 10-
20 rows of cells called corneocytes.
• These cells are non-nucleated, scaly in
shape and consist of a tough cell envelope.
• In the interior of the cells there are densely
packed keratin filaments.
• The cells in the lower parts of the stratum
corneum, which is also called the stratum
compactum, are connected to each other,
are thicker, have more condensed parallel
bundles of keratin filaments and a weaker
keratin sheath.

23. Stratum corneum
• Cells in the outer part of this layer, called stratum
disjunctum, tend to desquamate due to loss of
cohesive structures, primarily due to proteolytic
degradation of desmosomes.
• In cases where this degradation is slowed down,
hyperkeratosis occurs.
• The basic function of the stratum corneum is to
provide mechanical protection of the skin and
create a barrier that prevents water loss from the
skin.
• At the same time, the stratum corneum prevents
the passage of soluble substances from the
environment into the skin.

24. • The process of keratinization - keratopoiesis
• Keratinization is a complex biochemical process in which the
cells of the epidermis mature and the stratum corneum is
formed, which is composed of cells filled with the fibrillar
protein keratin. In the normal process of keratopoiesis, living
cells of the epidermis turn into "dead" armed lamellae.
• The basal keratinocyte reaches the stratum corneum in
about 14 days, and the next 14 days are required for the
stratum corneum to reach the surface of the stratum
corneum, where it falls off as a mature keratinocyte.
• The transit time thus amounts to 28 days.

25. Melanocytes and melanogenesis
• Melanocytes are dendritic cells distributed
between the basal cells and are responsible for
skin color.
• They are characterized by light cytoplasm, an
oval nucleus and the presence of melanosomes.
• Melanocytes retain the ability to replicate
throughout life, thus maintaining the epidermo-
melanin units.

26. Melanocytes and melanogenesis
• The difference in skin color between races is the
result of genetically determined differences in the
amount of synthesized melanin and its distribution.
• Skin color depends mainly on the number, size and
packaging of melanosomes in the cells. In white
people, melanin granules are located in
melanosome complexes, while in black people, they
are diffusely distributed in keratinocytes.

27. Merkel cells
• Merkel cells are neuroendocrine cells of
the epidermis that originate from the
ectoderm (neural crest) and are located
in the basal layer that inhabit the
second trimester of pregnancy.
• These cells are not present in all areas
of the epidermis, but in special regions,
such as the lips, the oral cavity, the
outer side of the tooth root, hair
follicles and the skin of the fingers.
• The function of Merkel cells is not fully
understood, it is believed that they
represent mechanoreceptors that serve
for tactile sensitivity.

28. Langerhans cells
• Langerhans cells are of mesenchymal
origin.
• They are located both in the epidermis
and in the dermis, and here they
migrate in the 3rd embryonic month,
4-5 weeks after the migration of
melanocytes.
• Langerhans cells belong to dendritic
cells, which are also found in other
parts of the body and are antigen-
presenting cells in primary and
secondary immune responses.
• They originate from the stem cells of
the bone marrow.

29. Langerhans cells
• Langerhans cells are important for the formation of type IV
allergic reactions and play an important role in the recognition,
acquisition, processing and presentation of antigen specific T-
lymphocytes.
• They are located in the middle part of the spinous layer and in
the upper part of the outer coat of hair. In the course of immune
events, they can migrate from the epidermis to the dermis and
further through the afferent lymphatic vessels to the draining
lymph nodes.

31. Basement membrane
• It is a pink undulated homogenous
area between the epidermis and
dermis
• It consist of number of proteins.
• It is the site of attack injury in
blistering diseases.
• The basic functions of the dermo-
epidermal junction are:
Connecting the epidermis to the
dermis, Regulation of basement
membrane permeability, Dermo-
epidermal morphogenesis, Barrier
for inflammatory and neoplastic
processes, Participation in
immune and autoimmune events.

32. Basement membrane
Formed by:
• Plasma membrane of basal
cells and hemidesmosomes.
• Thin clear amorphous space
(lamina lucida).
• An electron dense area
(lamina densa ).
• Anchoring fibrils that anchors
the epidermis to dermis .

33. Dermis
• Dermis is the thickest and most important part of the skin.
• At the same time, the dermis is the largest part of the skin
covering. It is located between the epidermis and the hypodermis
and is composed of a network of collagen, elastic and reticulin
fibers, cells and an extracellular amorphous matrix composed of
proteoglycans and glycoproteins.
• Hair follicles, sebaceous and sweat glands, blood and lymph
vessels and nerves are located in it.

34. Skin structure
Dermis: is divided into
• Papillary dermis.
• Reticular dermis.
Consists of :
1)Collagen fibers:
• Provides strength
• Thin fibers in papillary
dermis but thick and coarse
in the reticular dermis .

35. Skin Structure
2) Elastic Fibers:
• Provides elasticity
• Protection against
shearing forces.

36. Skin structure
3) Ground substance:
Binds water and maintains
the skin turgor.
4) Blood vessels:
To nourish the overlying
epidermis also.
5) Fibroblasts:
Produce the above elements.

37. Skin Structure
Function of dermis:
• It provides nourishment to the
epidermis and interact with it
during wound repair.
• It gives the skin its strength,
elasticity, and softness.

38. Skin innervation
• Skin is innervated by at least a million nerve fibers and is considered
the largest receptor organ.
• Palms, feet, face and genitals have a particularly rich innervation, while
the skin of the back is sparsely innervated. Meissner's corpuscles are
found in the papillae of the dermis, mainly in the hairless skin (palps of
the fingers).
• They represent the mechanoreceptors responsible for the perception
of touch. Vater-Pacini (Vater-Pacini) lamellar corpuscles are
mechanoreceptors sensitive to vibrations and pressure. Golgi-Mazzoni
(Golgi-Mazzoni) corpuscles are predominantly located in the
subcutaneous tissue of the hands and are sensitive to moderate
pressure. Krause's corpuscles transmit the sensation of coldness.
Ruffini corpuscles are heat receptors.

39. Skin structure
Subcutaneous Fat:
• lies below the dermis.
• Attach the skin to underlying
bone and muscle as well as
supplying it with blood
vessels and nerves.
• The main cell types are
fibroblasts, macrophages
and adipocytes .

40. Skin Structure
Skin Appendages: include
• Eccrine/ apocrine
sweat glands.
• Sebaceous glands.
• Hair Follicles.
• Nails

41. Sweat glands
• According to the method of secretion, sweat
glands are divided into apocrine and eccrine.
• Apocrine glands secrete secretions by
separating the apical part of the cell, while the
secretion of eccrine glands is not accompanied
by the separation of cell material.
• The total number of sweat glands varies
between 2 and 4 million, and also their density
from 64/cm2 on the back to 620/cm2 on the
soles, where it is the highest.

42. Skin appendages
Eccrine sweat glands:
• Tubular structures open freely on
the skin ;not attached to hair
follicles.
• Under the influence of
cholinergic stimuli.
• Present everywhere except the
vermilion border; nail beds ; labia
minora and glans.
• Abundant in palms and soles.

43. Skin appendages
Apocrine sweat glands:
•Secrete viscous material that give
musky odor when acted upon by
bacteria.
•Present in the axillae ; anogenital
area ; modified glands in the external
ear canal ; the eye lids ( moll’s glands )
; and areolae.
•Under adrenergic stimuli.

44. Sebaceous glands
The development of the sebaceous glands takes
place simultaneously with the differentiation of the
epidermis and hair follicles in the period from the
3rd to the 15th week of embryonic development.

45. Skin appendages
Sebaceous glands:
• Attached to hair follicles or open freely.
• Present in the scalp, forehead,
face,upper chest except palms and
soles.
• Secrete sebum to moisturize the skin.
• Sebaceous glands are under the
control of androgens.

46. Skin adnexa
Hair (pili)
• Hairs are elastic structures that extend over the entire surface of the
skin with the exception of the palms, soles, dorsal sides of the distal
phalanges of the fingers, the inner side of the prepuce, the glans penis
and the inner side of the labia minora and labia majora. They are
densest on the scalp. According to the degree of maturity, there are
three types of hair. Lanugo are fetal hairs and they are replaced by
vellus and terminal hairs at the end of fetal life. Vellus hairs are short
and thin, without a medulla, and cover most of the body. Terminal
hairs are longer and thicker. They are found on the scalp, eyelashes and
eyebrows and beard of adult men.

47. Skin Appendages
• Hair follicles:
• Hair follicle has the hair shaft,
hair bulb and the bulge.
• Pilosebaceous unit include: hair
follicle+sebaceous gland+
arrector pili muscle.

48. Skin appendages
Nails:
• The nail plate is formed of hard
keratin.
• The first embryonic nail element
appears in the 9th week.
• Proximal nail fold morphology
can be altered in connective
tissue disease .
• The lunula is the visible part of
the matrix.
• The matrix covers the
midportion of the distal Phalanx.

49. Skin appendages
• Fingernails grow
3mm/month.
• Toenails grow
1mm/month.
• Nails can be affected in
systemic and skin
diseases

50. STRUCTURE OF THE MUCOUS SKIN OF THE LIPS AND ORAL SAVINGS
The structure of the mucous membrane of the lips and oral cavity differs from the
structure of the skin and consists of squamous-layered epithelium, under which
there is a connective tissue stroma (lamina propria). There are three types of
mucous membrane in the oral cavity in terms of structure and thickness: Frictional
and masticatory mucosa - covers the right and front part of the hard palate; it
armors, and the lamina propria is compact and firmly attached to the substrate.
Integumentary mucosa - covers the lips, cheeks and under the lips; it does not
arm, it is built only from the basal and spinous layer, and the superficial cells are
flattened.
Highly specialized mucosa covered with 4 types of papillae and localized on the
dorsal side of the tongue: Papillae filiformes - conical papillae; they are the most
numerous, give the tongue a velvety appearance and are located in front of the
terminal sulcus Papillae fungiformes - mushroom papillae; they are distributed on
the top and sides of the tongue; Papillae circumvallatae - rampant papillae; they
are located along the terminal sulcus; Papillae foliate - leafy papillae; they are
arranged along the lateral edges of the back of the tongue; they consist of
lymphoid tissue and are part of Waldeyer's ring.

51. Lecture Outlines
• Function , Structure of the skin.
• Approach to dermatology patient.
• Descriptive Terms and morphology of skin
lesions.
• Important signs and Investigations.
• Topical therapy.

52. ANAMNESIS AND DERMATOLOGY STATUS
Anamnesis is a set of data obtained from the patient (or his family), and it refers both to
the disease for which he is seen by the doctor, as well as to his previous diseases, as well as
diseases in the family. When taking an anamnesis in dermatology, it is good to perform a
short orientation examination before hand in order to conclude in which group of
dermatoses the existing disease belongs.
Anamnesis morbi: Refers to the time and place of the appearance of the first changes on
the skin and the duration of the disease until the moment of examination.
Anamnesis vitae: Data in chronological order about previous illnesses, traumas,
hospitalizations and surgical interventions, allergies, lifestyle habits.
Anamnesis familiae: In cases of genodermatoses, some allergic diseases (atopy), infectious
diseases (scabies, pediculosis, mycosis, TB), it is necessary to obtain precise data on the
existence of these diseases in the closest relatives. It is also known for some diseases that
there is a hereditary predisposition to the disease (psoriasis), so even in these cases it is
necessary to insist on the existence of the disease in the family.

53. Dermatological status is a description of the state of
changes in the skin and visible mucous membranes of the patient
at the time of examination.
• The dermatological status must include:
• type of changes (efflorescence),
• localization,
• distribution,
• color,
• shape and size of the lesions,
• possibly consistency,
• as well as limitation and relationship to the surrounding healthy skin.

54. Approach to Dermatology Patient
Step 1: Start with basics
• Age
• Race
• Sex
• Occupation

55. Approach to Dermatology Patient
Step 2 : History of skin lesion
• When? Onset.
• Where? site of onset.
• Extension of lesions.
• Evolution.
• Associated symptoms.
• Aggravating factors.
• Treatment.

56. Approach to dermatology patient
• Past medical history.
• Family history.
• Drug history.
• Occupational, travel
and social history.

57. Examination
 Use good light
when examining a
patient.
 Examine hair, nails
& mucous
membrane.

58. Examination
Describe..
• General appearance of patient.
• Distribution of lesions.
• Arrangement.
• Type.
• Shape.
• Color.
• Size.

59. Examination
Palpation:
• Look for consistency,
mobility, depth and
tenderness.

60. Distribution
Generalized :can be
• Symmetrical:
1.Universal (head to toe).
2.Bilateral.
• Asymmetrical:
1.Diffuse.
2.Unilateral.

61. Distribution
Localized:
• Acral.
• Malar.
• Sun exposed.
• Trauma sites.
• Flexures.
• Specific part.

62. Lecture outlines
• Function , Structure of the skin.
• Approach to dermatology patient.
• Descriptive Terms and morphology of skin
lesions.
• Important signs and Investigations.
• Topical therapy.

63. Descriptive Terms (Arrangement)

64. Descriptive Terms
Photodistribution:
• Lesions occurring over
sun exposed skin.
• Protected areas
remain free of lesions.

65. Descriptive Terms
Linear:
• Forms a line .

66. Descriptive Terms
Dermatomal:
• Occurring within the
distribution of nerve.

67. Descriptive Terms
Annular:
• Ring like .

68. Descriptive Terms
Herpitiform/Grouped:
• Lesions grouped in a manner
similar to herpes simplex
lesions

69. Descriptive Terms
Reticular:
• Net like .

70. Descriptive Terms
Verrucous, warty,
papillomatous:
• Surface consisting of
finger like projections.

71. Descriptive Terms
Nummular/discoid:
• coin like lesions.

72. Descriptive Terms
Guttate:
•Drop like, “en gouttes”.

73. Descriptive Terms
Targetoid:
• Round lesions with
concentric border and
a dark center.
• Iris like.

74. Descriptive Terms
Umbilication:
• Round depression in
the center.

75. DIAGNOSIS IN DERMATOVENEROLOGY EFLORESCENCES OF THE SKIN
• Efflorescences are clinical symptoms of skin diseases.
• These are characteristic visible changes on the skin and visible mucous
membranes that are the result of pathological events under the
influence of various agents.
• Although they are generally not specific for the disease and the
causative agent, they are invaluable for the diagnosis of skin diseases.
• Primary efflorescence is a direct consequence of pathological events
in the skin.
• During evolution, it can change its appearance and develop into a
secondary efflorescence, either spontaneously or under the influence
of various factors (therapy, trauma).

76. Efflorescence

77. macula erythema
hyperpigmentation hypopigmentation
Rash (exanthema) enantema

78. bula (blister) vesicle pustule
papula plaque
crust squama (scale)

79. urtica nodus vegetation
ulcus erosion

80. Morphology
Skin lesions are divided into:
• Primary =Basic lesion.
• Secondary= Develop during
evolution of skin disease or
created by scratching or infection

81. Morphology
• Primary lesions
• Macule/patch
• Papule/plaque
• Nodule
• Cyst
• Wheal
• Secondary lesions

82. Morphology
• Primary lesions
• Vesicle/bulla
• Pustule
• Purpura
• Secondary lesions
• Excoriation
• Erosion
• Scale
• Fissure
• Ulcer

83. Primary Skin Lesions
Macule :
• A flat circumscribed area
of altered skin color less
than 1 cm in size.
• Lacks surface elevation
or depression.

84. Primary lesions
Patch:
• Flat circumscribed skin
discoloration;
• More than 1cm.

85. Primary Skin Lesions
Papule :
• Elevated, Solid lesion
• < 0.5cm in diameter.

86. Primary Skin Lesion
Plaque:
• Elevated, solid confluence or
expansion of papules .
• > 0.5cm in diametern(lacks a
deep component ).

87. Primary Skin Lesions
Nodule:
• Elevated, Solid lesion.
• > 0.5 cm in diameter; with deep
component.

88. Primary Skin Lesions
Cyst:
• Closed sac-like lesion that contain
liquid or semi-solid substance.
• Usually soft and has depth.

89. Primary Skin Lesions
Vesicle:
• Elevation that contains clear fluid
< 0.5cm in diameter.
Bulla:
• Localized fluid collection. >0.5cm
in diameter (large vesicle).

90. Primary Skin Lesions
Purpura:
• Extra-vasation of red blood cells
giving non- blanchable
erythema.

91. Primary Skin Lesion
Wheal:
• A transient, edematous slightly
raised lesion, characteristically
with a pale center and a pink
margin.

92. Primary Skin Lesions
Pustule:
• Elevation that contains purulent
material.

93. Secondary Skin Lesions
Scale:
• Thick stratum cornium

94. Secondary Skin Lesion
Crust:
• A collection of cellular debris,
dried serum and blood .
• Antecedent primary lesion
usually a vesicle, bulla, or pustule.

95. Secondary Skin Lesions
Erosion:
• A partial focal loss of epidermis
that heals without scarring.

96. Secondary Skin Lesions
Excoriation:
• Linear erosion induced by
scratching.

97. Secondary Skin Lesions
Fissure :
• Vertical loss of epidermis and
dermis with sharply defined walls,
(crack in skin).

98. Secondary Skin Lesion
Ulcer:
• A full thickness focal loss of
epidermis and dermis; heals
with scarring

100. Secondary Skin Lesions
Scar:
• A collection of new
connective tissue.
• May be Hypertrophic or
Atrophic.
• Implies dermoepidermal
damage.

101. Secondary Skin Lesions
Lichenification:
• Increased skin markings
secondary to scratching.

102. Lecture Outlines
• Function , Structure of the skin.
• Approach to dermatology patient.
• Descriptive Terms and morphology of skin
lesions.
• Important signs and Investigations.
• Topical therapy.

103. Important Sign in Dermatology
NIKOLSKY SIGN:
• Rubbing of apparently normal
skin induce blistering.
• Seen in pemphigus vulgaris
and toxic epidermal necrolysis
(TEN)

104. Important Signs in Dermatology
AUSPITZ SIGN:
• Removal of scale on top of a
red papule produces
bleeding points.
• Seen in psoriasis.

105. Important Sign in Dermatology
Koebner’s phenomenon:
Trauma to the skin re- produce certain
diseases like:
• Psoriasis
• Vitiligo
• Lichen planus.
• Warts.

106. Important Signs in Dermatology
DERMATOGRAPHISM:
• Firm stroking of the skin produce
erythema and wheal.
• Seen in physical urticaria.
• In patient with atopy, stroking
produces white dermatographism
ratherthan red.

107. Investigations
Wood’s lamp:
Produces long wave UVL (360 nm)
Useful in:
•Tinea Versicolor-yellowish green
flourescence.
•Tinea Capitis -yellow green
flourescence in M.canis, M. andouini.
•Vitiligo - Milky white.
•Erythrasma –coral red flourescence.
•Melasma becomes more intensefied.
•

108. Investigation
KOH preparation for fungus:
• Cleanse skin with alcohol Swab.
• Scrape skin with edge of microscope
slide onto a second microscope slide.
• Put on a drop of 10% KOH.
• Apply a cover slip and warm gently.
• Examine with microscope.

109. Investigation
Tzank smear :
Important in diagnosing:
• Herpes simplex or VZV
(multinucleated giant
cells).
• Pemphigus Vulgaris
(acantholytic cells).

110. Tzank smear
• Select a fresh vesicle.
• De-roof and scrape base of
the vesicle.
• Smear onto a slide.
• Fix with 95% alcohol.
• Stain with Giemsa stain.
• Examine under
microscope.

111. Investigation
Prick test :
• Primary method for the
diagnosis of IgE mediated
allergies in most allergic
diseases.
• Useful in the diagnosis of hay
fever allergy, food allergy,
latex allergy, drug allergy and
bee and wasp venom allergy.

112. Prick test
• Put a drop of allergen containing
solution.
• A non bleeding prick is made
through the drop.
• After 15-20 min the antigen is
washed , the reaction is recorded.
• Positive test shows urticarial
reaction at site of prick.
• Emergency therapeutic measures
should be available in case of
anaphylaxis.

113. Investigations
PATCH SKIN TEST:
• Useful diagnostic test for patients
with allergic contact dermatitis.
• Select the most probable substance
causing dermatitis.
• Apply the test material over the
back.

114. PATCH SKIN TEST
• Read after 48 & 72 hr.
• Positive patch test showing
erythema and edema.
• In severe positive reaction vesicles
may be seen.

115. Investigation
SKIN PUNCH BIOPSY:
• Clean skin with alcohol.
• Infiltrate with 1-2% xylocaine
with adrenaline.
• Rotate 2-6 mm diameter
punch into the lesions.

116. SKIN PUNCH BIOPSY:
• Lift specimen and cut at base of
lesion.
• Fix in 10% formalin
• For Immunoflourescence put in
normal saline.
• Suture if 4 or 5 mm is used.

117. Investigations
Direct immunoflouresence DIF:
• Used to diagnose
autoimmune diseases e.g.
Pemphigus Vulgaris, Bullous
pemphigoid
• Detects immunoglobulin and
complement deposits in
skin.
• The deposits will give a
green fluorescence

118. Investigations
Indirect ImmunoFluorescence : IDIF
• Detect auto antibodies in the serum.
It is used:
• To confirm a diagnosis.
• To differentiate between bullous
diseases.
• To monitor disease activity.

119. Lecture Outlines
• Function , Structure of the skin.
• Approach to dermatology patient.
• Descriptive Terms and morphology of skin
lesions.
• Important signs and Investigations.
• Topical therapy.

120. According to the active substance, drugs for local application can
be:
• keratolytics,
• antiseptics,
• Antibiotics,
• Antimycotics,
• Antivirals,
• Antiparasitic drugs,
• Corticosteroids,
• Discount funds,
• cytostatics,
• retinoids,
• Means for stimulating epithelization,
• Photoprotective means.
Topical therapy

121. Topical Therapy
• A wide variety of topical
agents are available.
• Delivers the drug to target
site.
Golden rule:
• IF the lesion is dry -wet it
• iF wet -dry it.

122. Topical Therapy
Topical drugs consist of:
• Active substance: like
steroids, antimicrobial
agents.
• Vehicle: Is the base in
which the active
ingredient is dispersed.

123. Topical therapy
Topical steroids side effects:
• Atrophy and striae.
• Telangiectasia and purpura.
• Masking the initial lesion.
• Perioral dermatitis and rosacea or acne.
• Systemic absorption.
• Tachyphylaxis (sudden loss of response).

124. Topical therapy
Guidelines regarding steroid use:
• Avoid high potency steroid on flexures and
face.
• Avoid high potency steroid in children.
• Avoid use for extended periods of time.

125. Topical Therapy
• Cream is 50 % oil and 50 %
water.
• creams are useful in wet
lesions.
• They are white in color.

126. Topical Therapy
• Ointment is 80 % oil and 20 %
water.
• Ointments are useful in dry
lesions.
• They are translucent.

127. Topical Therapy
• Gels are mixtures of propylene
glycol and water.
• Sometimes they contain
alcohol.
• They are translucent.
• used in wet lesions and hairy
regions.

128. How much to use?
Finger tip unit:
• The amount of
cream/ointment
expressed from 5mm
nozzle.
• It weighs 0.5g.
• It covers 2 hand units.

129. Finger Tip Unit

130. SYSTEMIC THERAPY
• Antibiotics
• Antimycotics
• Corticosteroids,
• antihistamines,
• Antimalarials,
• sulfonamides,
• sulfones,
• cytostatics,
• immunosuppressants,
• Antiviral drugs,
• Antituberculosis drugs,
• Antiparasitic drugs,
• anti-inflammatory drugs,
• vitamins,
• hormones,
• Biological drugs.

131. PHYSICAL THERAPY
• kinesitherapy,
• Thermotherapy,
• cryotherapy,
• electrotherapy,
• Rariotherapy,
• sonotherapy,
• Phototherapy.
SURGICAL THERAPY
Small surgical procedures, such as incision, curettage, biopsy, etc. are
applied in everyday dermatological practice. Larger procedures on the skin
belong to dermatosurgeons or plastic surgeons.

132. Phototherapy machine/NBUVB
Other therapeutic modalities

133. Hand and feet narrow band UVB

134. Vitiligo treated by NBUVB
Other indications include psoriasis
lichen planus and atopic dermatitis.

135. • Liquid nitrogen gun
(Cryotherapy).
• Used to treat warts.

136. THANK YOU