RESUMEN
Acne fulminans (AF) is a rare and severe form of inflammatory acne presenting clinically with an abrupt outburst of painful, hemorrhagic pustules and ulceration, that may or may not be associated with systemic symptoms, such as fever, polyarthritis, and laboratory abnormalities. It typically affects male teenagers with a pre-existing acne. Although the pathogenetic mechanism has not been established yet, a role of genetic, abnormal immunologic response, drugs intake, hormonal imbalance and viral infection, as causal factors, has been identified. AF may occur as a single disease or may be associated with other disorders. Traditionally, AF has been classified, on the basis of the presence of systemic involvement, in "acne fulminans" and acne fulminans "sine fulminans," when no systemic involvement is present. Recently, four clinical variants have been proposed: acne fulminans with systemic symptoms (AF-SS), acne fulminans without systemic symptoms (AF-WOSS), isotretinoin-induced acne fulminans with systemic symptoms (IIAF-SS), isotretinoin-induced acne fulminans without systemic symptoms (IIAF-WOSS). The diagnosis of AF is usually based on clinical history and physical examination. No specific laboratory abnormalities are generally found. In selected cases, biopsy and/or radiologic imaging are helpful for a correct diagnosis. The treatment significantly differs from severe acne according to severity of clinical presentation and possible systemic involvement. Currently, systemic corticosteroids (prednisolone) and retinoids (isotretinoin) represent the first choice of treatment. Dapsone, cyclosporine A, methotrexate, azathioprine, levamisole, and biological agents such as anakinra, infliximab, adalimumab may be considered as alternative therapies in selected cases. Adjunctive topical and physical therapies may also be considered.