Acute generalized exanthematic pustuloses supervening without a genetic psoriatic predisposition are not exceptional if the literature over the last few years is taken into account. Such observations are published under a wide range of names. Beside exanthematic pustular psoriasis as defined by Baker and Ryan, there exists in fact a whole scale of amicrobial pustulosis: acute generalized pustular bacterid; acute generalized pustulosis manifestation of leukocytoclastic vasculitis; pustular necroziting angeitis; pustular eruption with eosinophilic abscesses; generalized pustular drug rash; subcorneal pustules in erythema multiforme and in Sweet's syndrome. Thus, it appears that pustuloses exist in many forms, although they have certain common points that justify a synthetic perspective:--their occurrence, after a bout of infection and/or after taking drugs in subjects with no previous known psoriasis;--a single outbreak occurring spontaneously or with corticoid therapy and which heals by itself;--the existence of a marked vasculitis which occurs before the epidermal pustules. Sometimes this takes the form of a leucocytoclastic vasculitis or a polymorphic infiltrate which is rich in intact eosinophils. Direct immunofluorescence shows deposits of C3 and occasionally IgM at the vascular wall. The circulating antibody-antigen complex produced by an infection and/or by a drug may be responsible of the pustulosis by a hypersensibility mechanism (type Arthus phenomen). From the existing literature and the personal observations of four cases, the authors have made a general review of these pustuloses. They believe that in the majority of cases, pustulosis should not be considered as being psoriatic. However, the authors discuss the rare but possible occurrence of such a pustulosis in patients with a genetic psoriatic predisposition. They feel it would be preferable to avoid the publication of observations under a too wide a range of names, and propose the common heading of "acute generalized exanthematic pustulosis".