A surgeon's nightmare: pyoderma gangrenosum with pathergy effect mimicking necrotising fasciitis

A 53-year-old woman was admitted for vulval swelling and fever. She was initially diagnosed with vulval cellulitis and given parenteral antibiotics. Within 1 week, she developed necrotic-looking skin lesions extending from her vulva to her buttock. Emergency surgical debridement with diversion colostomy was performed in view of suspected necrotising fasciitis. Shortly after the surgery, she developed necrotic-looking skin lesions at the peripheral venous cannula insertion site, central line insertion site, and around her surgical wounds and stoma. A second surgical debridement was performed and shortly afterwards, similar skin lesions appeared around her surgical wounds. Her clinical progression was suggestive of pyoderma gangrenosum with pathergy effect. Hence, she was started on topical steroid, systemic steroid and immunosuppressant. The skin lesions responded well to medical therapy. Further systemic workup for conditions associated with this disease revealed findings suspicious for myelodysplastic syndrome.