A 51-year-old previously healthy man was hospitalized for a rapidly progressive, painful eruption on the face, neck, trunk, arms, and thighs and partial destruction of the nasal cartilage. Prior to admission, he was treated with oral antibiotics and prednisone, 120 mg/d, for 4 weeks without response. Physical examination revealed numerous 2-mm to 2-cm papulopustules and skin ulcers arising on an erythematous base. Some of the ulcers had necrotic, crusted centers and boggy, violaceous borders (Figure, A). Active ulcers were present on the tongue, pharynx, and nasal mucosa. Extensive laboratory evaluation revealed only an elevated white blood cell count of 13 700/μL with 83% neutrophils and a C-reactive protein level of 105.2 mg/L. (To convert white blood cells to ×109 per liter, multiply by 0.001; to convert C-reactive protein to nanomoles per liter, multiply by 9.524.)