Secukinumab-induced ulcerative colitis in a patient with psoriasis successfully treated with risankizumab

Interleukin (IL) 17A antagonists are increasingly used for psoriasis and other indications such as ankylosing spondylitis or hidradenitis suppurativa but can paradoxically trigger inflammatory bowel disease (IBD). We present a 51-year-old male patient with psoriatic arthritis who developed ulcerative colitis (UC) 12 months after initiating secukinumab therapy. Colonoscopy revealed continuous colonic inflammation with large ulcers in the rectum (Montreal E3). Faecal calprotectin was 87 µg/g. Secukinumab was discontinued and therapy with mesalazine was initiated. To ensure continued psoriasis control and treatment of UC, risankizumab, a selective IL-23 inhibitor, was administered at the standard psoriasis regimen. Over 12 months, the patient achieved clinical, endoscopic and histological remission. This case illustrates the dual role of IL-17A in mucosal immunity and risk of IBD induction by IL-17A blockade. Selective IL-23 inhibition may represent an effective strategy for managing IL-17A antagonist-induced UC while preserving psoriasis control.