A Case of Ischemia-Induced Perianal Ulceration Mimicking Pyoderma Gangrenosum.

A 68-year-old woman, with a 75-pack-year smoking history and a history of chronic excess alcohol intake, presented with a 5-week history of worsening perianal pain and ulceration. She recently had an inpatient admission with back pain and urinary tract infection during which she developed diarrhea and fecal incontinence. Initially, the perianal ulceration was diagnosed as severe irritant contact dermatitis and treated with barrier creams and topical clobetasone 17-butyrate 0.05% weight for weight, oxytetracycline 3.0% weight for weight and nystatin cream (Trimovate®). Despite this, the ulceration progressed, resulting in hospital readmission 1 month later. There was no history of consumption of nicorandil (an antianginal therapy), of recurrent oral ulcers, or of inflammatory bowel disease. On examination, there were multiple areas of deep, sloughy ulceration bilaterally around the perianal and buttock regions with erythematous and violaceous edges (Figure 1). Complete blood count, blood film, rheumatoid factor, autoimmune and vasculitic profile, hepatitis screen, immunoglobulins and plasma protein electrophoresis were all normal. Punch biopsy revealed scanty dermal perivascular inflammatory cell infiltrate and occasional neutrophils (Figure 2). No evidence of granulomata, dysplasia, malignancy, or Langerhans histiocytes was identified, and periodic acid-Schiff staining was negative.