A 72-year-old man presented to his primary care physician with a 1-month history of a lower extremity ulceration. Initially, he had noted a discrete area of warmth and erythema on the pretibial aspect of his right leg that did not blanch with pressure. He denied any recent history of trauma or travel. The area of erythema on his leg enlarged over the following weeks despite oral amoxicillin clavulanate therapy. His medical history revealed autoimmune hepatitis, for which he had been placed on an oral regimen of prednisone (40 mg/d) and azathioprine (50 mg/d) 4 months earlier. A large reticulated area of ulceration on his right lower extremity, with areas of full necrosis, was observed on physical examination. The border was well defined, erythematous, bluish, and violaceous (Figure 1). The results of a vasculitis workup (ie, serologic tests for antinuclear antibody, rheumatoid factor, and cardiolipin antibody; a cryoglobulin screen; and a cryofibrinogen screen) were negative.
Burgess MJ, Robson K, Chaffins M. Lower Extremity Ulceration in an Immunocompromised Patient—Quiz Case. Arch Dermatol. 2004;140(12):1531-1536. doi:10.1001/archderm.140.12.1531-a