Acute febrile neutrophilic dermatosis (Sweet's syndrome) and myeloproliferative disorders.

Acute febrile neutrophilic dermatosis (ND) consists of the abrupt onset of red, tender, cutaneous plaques on the face, extremities, and upper trunk, accompanied by fever, malaise, and neutrophilic leukocytosis. Histologically, there are distinctive, dense, dermal infiltrates of neutrophils. Response to systemic steroids is dramatic. This report describes four patients with leukemia or preleukemia and ND (LND), reviews reports of 12 similar patients, and compares LND with ND in otherwise healthy individuals (idiopathic ND, IND). Although lesions of LND more frequently had vesiculobullous appearances or location on mucous membranes, this study showed no consistent difference between LND and IND with regard to cutaneous signs, symptoms, histologic findings, and response to therapy. The first episode of LND either preceded or followed documentation of the myeloproliferative disorder, and the most common associated hematologic conditions were acute myeloid or myelomonocytic leukemia. Moderate to severe anemia was present in nine of ten patients whose first episode of LND preceded the discovery of the hematologic condition by eight months or less. The presence of anemia is the most obvious and readily detectable difference between LND and IND. The possibility of an underlying myeloproliferative disorder should be considered in all patients with ND, and LND should not be confused with infectious complications in patients known to have myeloproliferative disorders.