Acne fulminans and its multiple associated factors: a systematic review.

Acne fulminans (AF) is a severe form of acne that presents with an outburst of haemorrhagic pustules and ulcerations, which may or may not be associated with systemic symptoms and laboratory abnormalities. In the latest classification, four variants of AF are considered, but this does not include AF associated with systemic therapies and inherited genetic syndromes. To systematically review disease features and evaluate differences among AF. Related articles were searched using the terms "acne fulminans", "acne conglobata with septicaemia", "acute febrile ulcerative acne" and "pseudo acne fulminans". We searched Medline and Google Scholar from inception to 1977 to identify case reports, case series, commentaries and reviews reporting new AF cases. A total of 98 articles met our inclusion criteria. AF induced by higher levels of androgens more frequently presented nodules and cysts than erosions, crusted and haemorrhagic lesions and necrosis. In contrast, patients affected by AF without any apparent cause (referred to here as "miscellaneous AF") more frequently presented with ulcerations and erosions, and patients with AF associated with systemic treatment showed a similar frequency of lesions. Notably, AF in patients with high levels of androgens and AF induced by antibiotics rarely showed comedones. In addition, aseptic osteolytic lesions were more common in miscellaneous AF than other AF. AF may present with differences in clinical and laboratory features and associated systemic illnesses, which should be evaluated for the planning of a personalized therapeutic scheme. We propose a classification of AF, according to its association with certain factors.