Chronic tender ulcers on the calf and both forearms

An elderly woman presented with a 3-month history of nonhealing, tender ulcers involving the right calf and both forearms. She denied any history of similar lesions or trauma. Two trials of oral antibiotics had led to no improvement. Her medical history was significant for rheumatoid arthritis treated with methotrexate, hydroxychloroquine, and prednisone. A review of clinical manifestations was otherwise negative for disease. Physical examination of the patient’s right calf revealed two punched-out ulcers with central necrotic black eschars, underlying retiform purpuric pattern, and mild fibrinopurulent drainage (Figure 1). Similar lesions were present on her forearms (Figures 2 and 3). No other remarkable skin changes were noted. The differential diagnosis included polyarteritis nodosa, cutaneous necrosis secondary to antiphospholipid syndrome, cryoglobulinemic vasculitis, and an atypical presentation of pyoderma gangernosum.