MT Training > Terminology > Dermatology

Lesion Types:

• Macule : a circumscribed change in skin color without elevation or depression.
• Papule : a solid elevated lesion usually 0.5 cm or less in diameter.
• Plaque : a raised lesion that has a greater area as compared to its elevation above the skin surface.
• Wheal (hive) : a rounded or flat-topped elevated lesion formed by local dermal edema.
• Nodule: a palpable solid lesion of varying size, greater than 0.5 cm and less than 2 cm in diameter, which may be present in the epidermis, dermis or subcutis.
• Vesicle: a circumscribed elevated lesion which contains free fluid. Vesicles are 0.5 cm or less in diameter.
• Bulla, blister
• Pustule: (abscess) a circumscribed elevated lesion which contains pus. An abscess is usually in the dermis or subcutis.
• Purpura : a non-blanching erythema or violaceous color due to extravasation of blood into the tissue.
• Cyst: a sac containing liquid or semisolid material usually in the dermis.
• Scale : a heaping up of stratum corneum or keratin.
• Erosion : a loss of epidermis above the basal layer leaving denuded surface.
• Crust: an accumulation of serum, blood, or purulent exudate.
• Excoriations: linear crusts and erosions due to scratching.
• Ulcer: a loss of epidermis and part or all of dermis leaving depressed moist lesion.
• Atrophy : a thinning of epidermis or dermis.
• Sclerosis : a hardening or induration of skin.
• Scar : fibrous tissue replacing normal skin in areas of healing.
• Lichenification: (1) an accentuation of skin markings commonly associated with thickening of epidermis usually caused by scratching or rubbing. (2) marked by the presence of fine papules.
• Scar: a variety of dermal and epidermal changes associated with wound healing, cf. hypertrophic scar, keloid, post-inflammatory dyspigmentation
• Poikiloderma: a combination of atrophy, hyper and hypopigmentation and telangiectasis.
• Telangiectasia: dilated superficial blood vessels, especially of the upper reticular dermal plexus.
• Nikolsky's Sign: a disadhesion of skin assessed by light pressure at the edge of a preexisting bulla.

Configuration:

• linear - factitial, nevoid, Koebner phenomenon, autoinoculation.
• annular - ring-like-tinea, papulosquamous disorders and dermal processes.
• iris-target - erythema multiforme
• grouped - herpetiform.
• dermatomal - zosteriform (especially metastatic disease)

Distribution:

• light exposed - L.E., drugs, seborrheic dermatitis , Acne rosacea , Acne vulgaris , Acute Contact Dermatitis, Arms
• generalized - drug, infection
• palms and soles - Secondary syphilis , Rocky Mt. Spotted Fever, erythema multiforme
• intertriginous - Candida, tinea, erythrasma.

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