Sweet syndrome, also known as acute febrile neutrophilic dermatosis, is a rare inflammatory skin condition characterized by the sudden onset of painful, erythematous papules and plaques. It has been associated with underlying inflammatory bowel disease. We present a 24-year-old man with recently diagnosed ulcerative colitis on infliximab and methotrexate who was diagnosed by biopsy with Sweet syndrome. The patient was treated with multiple trials of steroids and biologics until finally showing improvement with upadacitinib. This case highlights the importance of considering Sweet syndrome in ulcerative colitis patients with atypical skin manifestations and the first documented case of Sweet syndrome treated with upadacitinib.
Keywords: Sweet syndrome; inflammatory bowel disease; ulcerative colitis; upadacitinib.
© 2025 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.