Acute generalized exanthematous pustulosis (AGEP) is now a well known clinical entity, characterized by acute onset with associated fever, and numerous non-follicular pin-head sterile pustules on erythematous background. The biopsy evidences subcorneal pustules resembling those of pustular psoriasis. However, polymorphic aspects such as pseudo erythema multiforme purpuric lesions, and edema are often associated, and with the rapid self-healing course of this impressive pustulosis, allow the differential diagnosis with pustular psoriasis. Most cases of AGEP are drug induced, particularly by antibiotics and mainly beta-lactams. However, a number of other drugs, of which the list is increasing, may be responsible. Few cases are related to other causative factors such as viral infections or ultraviolet radiation. Copyright (C) 1996 by W.B. Saunders Company.