S3705 Secukinumab-Induced Colitis: A Case Report

Introduction: We present a case of drug-induced colitis in a patient taking secukinumab. Secukinumab (Cosentyx) is an IL-17 inhibitor commonly used in dermatologic conditions such as plaque psoriasis, psoriatic arthritis, and hidradenitis suppurativa. It has been previously associated with colitis, but primarily new onset IBD or IBD exacerbations. The role of IL-17 in the gut is still under investigation, however it is associated with protective functions in epithelial barriers in the colonic mucosa. Case Description/Methods: A 33-year-old man with a history of hidradenitis suppurativa developed abdominal pain and bloody stools following his second loading dose of secukinumab, prompting workup. Colonoscopy identified diffuse areas of mildly erythematous mucosa without ulcers throughout the entire colon. Pathology of biopsies showed mild-to-moderate levels of active colitis and mild erosions in addition to basement membrane thickening and a non-specific expansion of the lamina propria by a top-heavy lymphoplasmacytic infiltrate. There was no evidence of chronic colitis, nor findings to support a specific infectious cause, supporting a drug-induced acute colitis. The patient discontinued the secukinumab and started a prednisone taper, which led to resolution of the symptoms. Discussion: The temporal relationship between secukinumab initiation and the onset of colitis, along with symptom resolution after drug discontinuation and corticosteroid therapy, supports a likely drug-induced etiology. There was no histologic evidence of underlying chronic inflammation or IBD, further supporting an acute drug induced colitis. Secukinumab’s likely role supports the theory of IL-17 playing a protective role in the colon, as inhibiting it induced symptoms. As biologics continue to play an important role in the treatment of many dermatologic, rheumatologic, and gastrointestinal disorders, understanding their side effects is important for the safety of patients. This case underscores the importance of considering drug-induced colitis in patients presenting with new-onset colitis after starting a biologic, even one not typically associated with gastrointestinal side effects.