Erythema annulare centrifugum as the presenting sign of the hypereosinophilic syndrome: observations on therapy.

A 79-year-old man with severe generalized pruritus and erythema annulare centrifugum as manifestations of his idiopathic hypereosinophilic syndrome slowly responded to long-term therapy with ketoconazole and dapsone. The skin lesions cleared within one month but the pruritus and eosinophilia required seven full months of therapy.