Background: Streptococcal infections can cause various skin manifestations related to the direct action of the offending organism itself or to a reactional mechanism. Reactional manifestations are less well known and understood, and they include generalized acute pustulosis belonging to the spectrum of neutrophilic dermatoses. We report a case of generalized acute pustulosis followed by Sweet syndrome and erythema nodosum occurring after a streptococcal infection.

Methods: A 60-year-old woman was consulting for a diffuse pustular rash after a throat infection, with high levels of anti-streptolysin (337 U/L) and anti-streptodornase (2560 U/L). The biopsy showed folliculitis and a neutrophilic infiltrator of the dermis, and bacteriological and mycological cultures were sterile. The patient then developed papules evoking Sweet syndrome followed by nodules typical of erythema nodosum after 20 days. A favourable outcome was achieved under colchicine.

Conclusions: Generalized acute pustulosis is a form of neutrophilic dermatosis whose mechanisms, area predilection and treatment are poorly known. The clinical presentation of this patient was initially typical and the secondary progression to lesions like those in Sweet syndrome is consistent with the pathophysiological continuity and overlap of these entities.