Indurated Plaque with Bullae Formation on the Left Arm.

A 72-year-old white man presented to the clinic with a tender, pruritic lesion on the upper part of his left arm that had progressively worsened over 4 months. Physical examination revealed an erythematous to violaceous, indurated, and sclerotic plaque with multiple foci of crusting and erosions (Figure 1). The patient denied any recent trauma, travel, fever, chills, weight loss, or constitutional symptoms. Before presentation, he had undergone treatment with cephalexin, prednisone, and doxycycline without reported improvement. Laboratory studies were negative for antinuclear antibody and SCL70 antibody; however, an absolute eosinophilia of 1478/uL was noted.