Pyoderma Gangrenosum

This rare condition of unknown cause belongs in the differential diagnosis of lower extremity vasculitis-like ulcerating lesions. It usually occurs in association with rheumatoid arthritis, inflammatory bowel disease, Wegener granulomatosis, chronic active hepatitis, and Behçet disease.¹

The lesion, which is usually singular, has an irregular, undermined, and raised border. It forms a painful ulcer, typically on the lower extremities or buttocks.