Concurrent Sweet's syndrome and erythema nodosum: a report, world literature review and mechanism of pathogenesis.

Sweet's syndrome (acute febrile neutrophilic dermatosis) and erythema nodosum are reactive dermatoses whose pathogenesis is currently undefined. Although there are several associated conditions that both of these disorders have in common, the appearance of Sweet's syndrome and erythema nodosum in the same person is rare. Only 8 individuals with biopsy confirmed lesions of both dermatoses were described in the world literature. We describe a 30-year-old woman with biopsy confirmed lesions of Sweet's syndrome on her hand and erythema nodosum on her legs. She had been taking an oral contraceptive and an appetite suppressant during the 5 months before these dermatoses appeared. Both cutaneous lesions rapidly responded to topical corticosteroid ointment and have not recurred since her medications were discontinued. The association of Sweet's syndrome and erythema nodosum is reviewed, their similarities discussed, and a pathogenesis is proposed.