Sweet's syndrome associated with trans-retinoic acid treatment in acute promyelocytic leukaemia

A case of acute promyelocytic leukaemia is reported in which Sweet's syndrome developed at the time of an improvement in white blood cell count due to transretinoic acid. Acute febrile neutrophilic dermatosis (Sweet's syndrome) is a disorder characterized by acute onset of inflammatory skin nodules associated with systemic features which include malaise, fever and neutrophilia. Many triggers and associated disorders have been identified since the syndrome was described, the most important being the association with haematological diseases including leukaemias and other myeloproliferative disorders. We describe a case apparently provoked by drug therapy.