Acute febrile neutrophilic dermatosis (Sweet's syndrome) associated with extreme infiltration of eosinophils.

A remarkable infiltration of eosinophils was observed in skin biopsy specimens in two cases of Sweet's syndrome. One patient was a 29-year-old woman, whose clinical and histological features included associated asthma, a prior respiratory tract infection, red plaques, blood eosinophilia, and a dense dermal infiltrate of neutrophils and eosinophils, without evidence of vasculitis. The other patient was a 61-year-old man characterized by a fever, red plaques, erythema nodosum-like lesions, hepatic dysfunction, a dermal infiltrate of neutrophils accompanied by eosinophils, and a subcutaneous prominent infiltrate of eosinophils. Clinical and histological evidence supported the diagnosis of Sweet's syndrome in both of these patients. While the literature describes eosinophil infiltration in this disease, extreme eosinophil infiltration could be misleading in the diagnosis.