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Pyoderma Gangrenosum — SCE Dermatology MCQ

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ModerateWound HealingPyoderma GangrenosumSCE Dermatology

A 65-year-old man develops a rapidly expanding painful ulcer on his left pretibial area 5 days after skin biopsy at that site. The ulcer has a violaceous undermined border with purulent base. He has a history of rheumatoid arthritis. His surgeon suggests debridement. Is surgical debridement appropriate?

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Correct answer: A — No — this is likely pyoderma gangrenosum which exhibits pathergy; surgical intervention will worsen the condition

This clinical scenario describes pyoderma gangrenosum (PG) arising at a biopsy site — demonstrating pathergy (worsening of disease at sites of trauma). PG is a neutrophilic dermatosis that exhibits pathergy in approximately 30% of cases. Surgical debridement is CONTRAINDICATED as it will extend the ulcer. Management is immunosuppressive: high-dose systemic Prednisolone (0.5-1 mg/kg/day) or Ciclosporin for rapid control, with steroid-sparing agents (Mycophenolate, Azathioprine) for maintenance. Topical super-potent corticosteroids or topical Tacrolimus may suffice for small/early lesions. The association with RA supports the diagnosis (PG is associated with IBD, RA, and haematological malignancy).

Reference: BAD 2022 PG Guidelines; STOP GAP Trial