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Pyoderma Gangrenosum — SCE Dermatology MCQ

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ModerateWound HealingPyoderma GangrenosumSCE Dermatology

A 47-year-old man presents with a longstanding ulcer on his left medial malleolus. The ulcer has irregular borders and a violaceous undermined edge. He has a history of ulcerative colitis. Biopsy shows neutrophilic dermal infiltrate with no evidence of vasculitis or infection. What is the most likely diagnosis?

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Correct answer: D — Pyoderma gangrenosum

Pyoderma gangrenosum (PG) classically presents with a rapidly expanding painful ulcer with a violaceous, undermined border. It is associated with inflammatory bowel disease (ulcerative colitis more than Crohn disease), rheumatoid arthritis, and haematological malignancies. Biopsy shows a dense neutrophilic infiltrate without true vasculitis (diagnosis of exclusion). PG exhibits pathergy — worsening with surgical debridement. Treatment involves systemic immunosuppression (prednisolone, ciclosporin) rather than surgical intervention.

Reference: BAD 2022 Guidelines for management of pyoderma gangrenosum