Terminology of Skin Disorders

Macroscopic appearances Macule (Fig. 7.1A) A flat, circumscribed lesion; an area of colour or textural change. Macules are seen in vitiligo (hypopigmentation), freckles (hyperpigmentation) and capillary haemangioma (red/purple). Papule (Fig. 7.1B) A solid, circumscribed, palpable elevation of skin less than 5 mm in diameter. They can appear in various forms: e.g. dome shaped (xanthomas), flat topped (lichen planus). Nodule (Fig. 7.1C) An elevation more than 5 mm in diameter that may be either solid or oedematous. Nodules are seen in rheumatoid arthritis, and a dermatofibroma is another example of this type of lesion. Plaque (Fig. 7.1D) A plaque is an extended, flat-topped lesion, a palpable elevation of skin (measuring no more than 5 mm in elevation but generally more than 2 cm in diameter). Plaques are commonly seen in psoriasis and mycosis fungoides (cutaneous T-cell lymphoma). Blister (Fig. 7.1E) A lesion of any size, filled with clear fluid, that forms because of cleavage of the epidermis. It may be a result of constant abrasion of the skin,