Lesions on the skin of a patient with Sweet's disease, also known as acute fibrile neutrophilic dermatosis. Although it can occur alone, Sweet's disease is often associated with hematological diseases, such as leukemia, and immunological diseases, for example rheumatoid arthritis and irritable bowel disease. The condition is more common in women from their mid to late fifties onwards. Treatment is with corticosteroid drugs, and is usually successful.