DERMATOLOGY TERMS

Macule
A circumscribed change in skin color without elevation or depression of the surface, e.g. purpura, café au lait spots, vitiligo.

Papule
A solid elevated area whose top may be flat, pointed, or rounded. It usually implies pathologic involvement of epidermal structures and the associated papillary dermis, e.g. acne, psoriasis.

Plaque
Evolves from a confluence of papules leading to development of larger, usually flat-topped circumscribed elevations, e.g. psoriasis.

Scale
Dessicated thin plates of cornified epidermal cells which result from altered keratinization, e.g. psoriasis, ichthyosis, chronic dermatitis.

Fissure
A deep linear split in the skin extending through the epidermis into the dermis.

Crust
Dried exudate of serum, blood, sebum, or purulent material on the surface of the skin, e.g. acute dermatitis.

Telangiectasia
Persistent dilation of individual venules in the skin, usually associated with alterations in the connective tissue of the dermis, e.g. scar.

Vesicle
Circumscribed elevated lesion containing serous fluid (a large vesicle is called a “bulla”). These may form within the epidermis or between the epidermis and dermis, e.g. acute dermatitis.

Pustule
A vesicle containing purulent exudate, e.g. acne.

Erosion
A moist, circumscribed, often depressed area which reflects loss of partial or full thickness epidermis. An erosion commonly implies a ruptured vesicle or bulla.

Wheal
A circumscribed, flat-topped, firm elevation of skin with a well-demarcated, palpable margin. It results from a tense edema of the papillary dermis.

Nodule
A small, solid, deep-seated mass in dermal or subcutaneous tissues. Usually a nodule produces visible elevation of the skin. When they involve the dermis, they move the skin over underlying tissues; when they are in the subcutaneous tissues, the skin moves over them, e.g. acne, tumors, and granulomas.

Lichenification
A dry, leathery, thickening of the skin with exaggerated skin markings. It is a thickening of all layers of the epidermis resulting from vigorous and repeated rubbing of the skin in chronic dermatitis.

Scar
An area of replacement fibrosis of the dermis or subcutaneous tissues resulting from antecedent destructive processes. Scars vary in texture and may be depressed or raised, e.g. acne, healed excoriations.

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