A 55-year-old woman with known ulcerative colitis develops a rapidly enlarging, deeply ulcerated wound on her lower leg following a minor trauma (phlebotomy). The wound has a violaceous undermined border with a boggy base and surrounding erythema. She describes the onset as extremely painful. Which phenomenon is associated with this condition and influences surgical management?

• A Pathergy — wound deterioration following trauma or surgery, making debridement contraindicated ✓
• B Koebner phenomenon — suggesting debridement will worsen the ulcer
• C Auspitz sign — bleeding on scraping indicates the diagnosis
• D Dermatographism — indicating mast cell activation

Explanation

Pyoderma gangrenosum (PG) is a neutrophilic dermatosis characterised by pathergy — the phenomenon whereby minor trauma (biopsy, surgery, IV cannulation) triggers or worsens the ulceration. This makes surgical debridement absolutely contraindicated in PG, as it paradoxically enlarges the wound. The undermined violaceous border and rapid enlargement in a patient with IBD are classic. Treatment is systemic immunosuppression (prednisolone, cyclosporine) or biologics (infliximab). Recognition of pathergy is critical to prevent iatrogenic harm.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.