A Woman with a Sore Spot on Her Leg

A 41 year old civil servant, with a background of poorly controlled Crohn’s disease, presented to her general practitioner with a skin lesion on her left shin that had been there for eight weeks (fig 1⇓). The lesion had started as a small red blemish, “like a burn,” that appeared acutely and rapidly grew in size. She could not recall any injuries to this area. It was painful to touch and she had noticed some purplish discoloration around the edges of the wound. Although it started to heal in some areas it was also enlarging at the periphery. She was worried about “passing it on” to her children and had covered it with a bandage. She had no known allergies and was taking sulfasalazine for her inflammatory bowel disease. ### 1. How would you describe the skin lesion? #### Short answer Irregular plaque with cribriform (uneven) scarring and purplish discoloration, multiple tiny ulcerations, and pustules at the edge. #### Long answer The lesion consisted of an inflammatory plaque measuring 7 cm in diameter, with cribriform (uneven) scarring and tiny ulcerations with pustules at the periphery (fig 2⇓). Although multiple clinical variants are noted (see long answer 2) the classic description of this lesion would be a painful ulcerative lesion, with a purulent base and well defined violaceous border.1 The border of the ulcer is often described as overhanging or undermined. This feature is caused by the spread of inflammation throughout the …