This document defines and describes various secondary skin lesions and special lesions. It discusses atrophy, erosion, excoriation, ulcer, scar, sclerosis, scale, crust, burrow, comedo, milium, telangiectasia, and target lesions. For each lesion, it provides details on clinical presentation, characteristics, and causes. Secondary lesions result from disruption of the skin surface, while special lesions have unique appearances or features.

1. SECONDARY AND
SPECIAL LESIONS
DR.B.SIVAJI YADAV

2. SECONDARY LESIONS
• ATROPHY
• EROSION
• EXCORIATION
• ULCER
• SCAR
• SCLEROSIS
• SCALE
• CRUST

3. ATROPHY
• It refers to a reduction in the components of a tissue, organ,
or part of the body.
• In the skin, atrophy may involve the epidermis,dermis, or
subcutis.
• EPIDERMAL ATROPHY
• Decrease in number of epidermal cells
• Presents as glossy paper thin and
wrinkled skin with alteration or loss of
normal skin markings

4. ATROPHY(contd)
• DERMAL ATROPHY
• Clinically detectable as depression of skin
• It is the consequence of a decrease in the papillary or
reticular dermal connective tissue and usually follows
inflammation or trauma with or without ulceration
• Usually associated with epidermal atrophy as in
striae,discoid lupus erythematosus

5. ATROPHY(contd)
• When atrophy involves the panniculus, as in progressive
lipoatrophy, liquefying panniculitis or lupus profundus, deep
depressions of the skin may occur.

6. EROSION
• This is a loss of part or whole of the epidermis but with
the dermis intact. Hence, healing occurs without scarring
unless secondarily infected.
• Erosions occur in epidermal blistering
disorders such as pemphigus Vulgaris
and epidermolysis bullosa.
• Erosions are superficial, often of
uniform depth, erythematous, and
covered with serous exudate.

7. EXCORIATION
• Excoriation result from scratching
and are characteristically linear.
• Commonly seen in pruritic disorders
such as atopic dermatitis and
scabies.
• LICHENIFICATION is a plaque of
thickened skin with accentuated skin
markings produced by constant
rubbing

8. ULCER
• An ulcer is a defect with a loss of
epidermis and at least part of the dermis
and they always heal with scarring.
• They may extend into and sometimes
even through the subcutaneous fat.
• The clinical features of an ulcer may help
determine the cause and these include the
location, borders, base, floor, and
surrounding skin.

9. ULCER(contd)

10. SCAR
• A scar is a visible alteration in the appearance of
the skin following repair of an injury and it reflects
the pattern of healing in areas of tissue destruction.
• The scarred epidermis is thin and devoid of normal
skin marking and appendages.
• Herpes zoster, tuberculosis and pyoderma
gangrenosum frequently result in hypertrophic as
well as atrophic scars
• Scars that continue to grow and extend into the
surrounding normal skin are known as keloids

11. SCARS(contd)

12. SCARS(contd)
HYPERTROPHIC SCAR
• Remain confined to
border of original wound
• Arise in any
location,commonly occur
on extensor surfaces of
joint
• Regresses with time
• Less association with skin
pigmentation
KELOIDS
• Extend beyond border of
original wound
• Commonly occur on
sternal
skin,shoulders,upper
arms,ear lobes and
cheeks
• Grow for years
• More common in darker
skin types

13. SCLEROSIS
• This is a circumscribed or diffuse hardening or
induration of the skin, more easily felt than
seen.
• It may result from dermal or subcutaneous
edema, cellular infiltrate, or increased
collagen.
• Seen in scleroderma,morphea, and chronic
lymphedema.

14. SCALES
• Abnormal shedding or accumulation of the
stratum corneum in visible flakes is called scaling.
• Under normal circumstances, the stratum corneum
sheds tiny invisible flakes in a continuous process in the
normal turnover of the skin.
• Scales form when there is either an excess production
or increased adherence of the cells of the stratum corneum
(preventing the normal dislodging of individual cells).

15. SCALES(contd)

16. SCALES(contd)

17. CRUST
• A crust results from dried up exudates on the
skin surface.
• It is a result of disruption of the skin surface.
• Crusts are usually secondary to some
preceding primary lesions such as vesicles,
bullae, or pustules.
• Removal of the crust may reveal an underlying
erosion or ulcer

18. CRUST(contd)
• When blood forms a major component
of the crust, it is often referred to as a
scab.
• The color of crust is a yellow-brown
when formed from dried serous
secretion
• turbid yellowish-green when formed
from purulent secretion and
• reddish-black when formed from
hemorrhagic secretion.

19. SPECIAL LESIONS
• BURROW
• COMEDO
• MILIUM
• TELANGIECTASIA
• TARGET LESION

20. BURROW
• A burrow is a serpiginous tunnel in the
skin made by the scabies mite.
• Burrows, about 5 mm in length, on the
fingers, wrist, or genitalia are
diagnostic of scabies.
• Longer burrows (5–10 cm) on the feet
are seen in creeping eruption (larva
migrans) caused by migration of
hookworm larvae.

21. COMEDO
• A comedo results from an impaction
within the pilosebaceous unit.
• They may be of two types: open and
closed
• In the open comedo (commonly termed
blackhead) the impaction occurs in a
dilated follicular orifice and is clinically
visible as a black keratinous mass.
• The black color of the comedo is due to
the oxidized sebaceous content of the
infundibulum (“blackhead”).

22. COMEDO(contd)
• In a closed comedo or “whitehead” the follicular openings
are not dilated, i.e. they are closed.
• The impaction occurs lower down in the follicular canal.
• The lesions appear as tiny papules somewhat lighter in
color than the surrounding skin.

23. MILIUM
• Milia are small, superficial cysts
with an epidermal lining.
• They occur on the face, especially
in the periorbital region
• Sometimes they may arise on
blistered or damaged skin, e.g.
after dystrophic epidermolysis
bullosa or porphyria.

24. TELANGIECTASIA
• These are distinctly visible
dilated capillaries.
• Seen in rosacea, actinic,and
radiation damage,
dermatomyositis,
scleroderma,
steroid-induced atrophy and
hereditary hemorrhagic
telangiectasia.

25. TARGET LESIONS
• These are pathognomonic of
erythema multiforme.
• Commonly found on the
extremities, especially hands
• Three zones of color change are
present—a central dark
sometimes blistered area
surrounded by a pale edematous
zone, which in turn is rimmed by
another zone of erythema

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