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Fifth stage
Dermatology
Lec-1
د
.منار
3/11/2016
MORPHOLOGY OF SKIN LESIONS
Structure of the skin:
The skin compose of three layers:
• Epidermis ( cells only )
• Dermis ( connective tissue , blood vessels and nerves)
• Subcutaneous layer : fatty layer protect the body from heat and mechanical trauma
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Primary lesions :
(original lesions ) produced by the disease it self
Macule,
patch
Papule,
plaque,
nodule,
tumor
cyst
Wheals
Vesicle
Bullae
Pustule
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B. Secondary Lesions:the primary lesions continue to develop or may be regress, or if it is
subjected to trauma , or due to the effect of itching , infection , or to the effect of treatment
:
Scales
Crusts
Ulcers
Excoriations
Erosions
Fissures
Scars-hypertrophic scars
Keloid
Lichenification
Primary lesions
Mucule: spot
• Circumscribed discoloration of the skin
• without elevation or depression
• of less than 1 cm in diameter
• Has a flat surface
• E.g. vitiligo , freckles
Patch
• If the discolaration is larger than 1 cm.
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Papule- (Latin Paula, “Pimple”)
• Are circumscribed,
• solid elevations of skin
• of less than 1 cm in the skin .
•
E.G. Acne , warts
Plaques: (French- Plaque- “Plate”)
•
if it is more than 1 cm or confluences of papules
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Nodules"
small knot
Similar to papule but it has two elements :
1. Depth.
2. Elevation of the epidermis
• e.g. : acne , leishmania
Tumors
• Soft or firm
• Freely movable or fixed masses
• of various sizes and shape.
“A tumor is an abnormal mass of tissue, the growth of which exceeds and un-coordinated
with normal tissue and persists in the same excessive manner after cessation of stimulus
which evoked the change”.
Cyst
a cyst is a cavity containing liquid or semi-solid
material may be superficial or deep.
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Wheals (Hives) wheals
• Circumscribed
edematous
papule
with
erythematous boarder and pale center, could be
of various size .
• It is evanescent ( transient ) takes few hours and
fade-away
• It is characteristic lesion of urticaria
• Vesicles “Little bladder” :
• are circumscribed epidermal elevations
• less than 1 cm in size
• and containing clear fluid.
Bullae ” Bubble ”:
• are circumscribed or irregularly shaped cavity
• more than 1 cm in diameter
• containing clear , serous or seropurulent fluid.
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Pustule (Pustula-Pus):
• circumscribed accumulation of pus in the skin
• of less than 1 cm in diamter .
Abscess :
• circumscribed accumulation of pus in the skin
• of larger than 1 cm in diamter
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Secondary Lesions
• Scales: are sheets of dead keratinocyte accumulated together , dry or greasy laminated
masses of keratin accumulated together before shedding
• Excoriations : an excoriation is a punctate or linear abrasion produced by mechanical
means usually involving only the epidermis and rarely reaching the papillary layer of
the dermis .
• Erosions: loss of all or portion of epidermis alone, heal without scar .
• Fissures : is a linear cleft or crack through the epidermis or rarely into the dermis
caused by disease (eczema ) or injury.
• Ulcers loss of epidermis and part of the dermis, heal with scar .
• Crusts are dried serum, pus or blood, usually mixed with epithelial and bacterial debris,
on the surface of the skin .
• Scars accumulation of fibrous tissue in the dermis or deeper parts as a result of injury
or disease, as a part of the normal healing process , scar may be hypertrophic or
atrophic
• Keloid (claw like ) is a firm, irregularly shaped, thickened, hypertrophic, fibrous, pink
or red excrescence.
• Lichenification : thickening of the skin with increase skin marke and
hyperpigmentation , as in chronic eczema
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