A case of sweet syndrome effectively treated with potassium iodide

Sweet syndrome, which was reported by Sweet in 1964, is characterized by a combination of fever, neutrophilia, tender erythematous nodules or plaques, and histopathologic findings showing a dense infiltrate of mature neutrophils in the upper dermis. Systemic administration of corticosteroids is the "gold standard" for the treatment of Sweet syndrome, and the dramatic response is well known. However, considering the underlying disease and various side effects, administration of corticosteroids may be harmful in some patients. We encountered a patient with Sweet syndrome who showed dramatic and rapid response to systemic administration of potassium iodide. The patient became afebrile and free from symptoms within 48 hours after starting potassium iodide, and there have been no recurrences after cessation of the therapy. Although the mechanism of action is not clear, potassium iodide can be a first line drug, because of its effectiveness, safety, and low cost.