ACNEIFORM DERMATOSES

Acneiform dermatoses are follicular eruptions. The initial lesion is i nflammatory, usually a papule or pustule. Comedones are later secondar y lesions, a sequel to encapsulation and healing of the primary absces s. The earliest histological event is spongiosis, followed by a break in the follicular epithelium. The spilled follicular contents provokes a nonspecific lymphocytic and neutrophilic infiltrate. Acneiform erup tions are almost always drug induced. Important clues are sudden onset within days, widespread involvement, unusual locations (forearm, butt ocks), occurrence beyond acne age, monomorphous lesions, sometimes sig ns of systemic drug toxicity with fever and malaise, clearing of infla mmatory lesions after the drug is stopped, sometimes leaving secondary comedones. Other cutaneous eruptions that may superficially resemble acne vulgaris but that are not thought to be related to it etiological ly are due to infection (e.g. gramnegative folliculitis) or unknown ca uses (e.g. acne necrotica or acne aestivalis).