Acute febrile neutrophilic dermatosis (Sweet's syndrome): case report and review of the literature.

An 8-month-old male infant had fever, polymorphonuclear leukocytosis, and tender, firm, elevated erythematous plaques on his face, trunk, and extremities. Histologic examination revealed a dense, perivascular, polymorphonuclear, inflammatory cell infiltrate with nuclear dust in the dermis and intrafollicular abscesses. The rash responded promptly and dramatically to oral corticosteroids. In our opinion, these features represent a distinctive hypersensitivity reaction consistent with acute febrile neutrophilic dermatosis (Sweet's syndrome). It seems that Sweet's syndrome has two age peaks: infancy and middle age. In the former, no sex predilection and no underlying malignancy have been recorded. In the latter, females are preponderantly affected and an associated underlying malignancy has been described.