(BMJ)—A 65-yo man—s/p subtotal colectomy w/ stoma for ulcerative colitis 18mo prior—presented w/ rapidly expanding, painful ulcers on his legs, perineum, and peristomal skin. No bowel sx. Off meds since surgery. Exam: fever; drowsy; ulcers w/ violaceous borders. Labs: raised CRP, WBC. What’s the dx?
Ecthyma gangrenosum
Pyoderma gangrenosum
Erythema nodosum
Sweet syndrome
Cutaneous lymphoma
You are correct. Painful, rapidly growing ulcers on a background of ulcerative colitis (UC) is consistent w/ ulcerative pyoderma gangrenosum and peristomal pyoderma gangrenosum. The condition is often misdiagnosed as infection or vasculitis. Initially, wound cultures are typically negative; however, after skin breakdown, they’re subject to secondary infection. Inflammatory markers may be raised because of underlying systemic dz or from the inflammation assoc w/ pyoderma gangrenosum.

Pyoderma gangrenosum is idiopathic in up to 50% of cases but can be assoc w/ UC, myelodysplasia, lymphomas, arthritides, and certain drugs. Approximately 30% to 60% of pyoderma gangrenosum cases are assoc w/ UC. Around 2% to 8.5% of pts w/ UC may develop pyoderma gangrenosum. The condition occurs less commonly w/ Crohn dz.

The pt responded to broad-spectrum abx and high-dose steroids. The ulcers healed after the addition of mycophenolate mofetil.

BMJ 2019;364:l847