Interferon-Induced Crohn’s Disease: An Unusual Side Effect of Interferon Therapy in a Patient With Chronic Hepatitis C Virus Infection

Gastrointestinal side effects of interferon (IFN) therapy for chronic hepatitis C virus (HCV) infection are non-specific. Rarely, this therapy has been reported to induce ischemic colitis and even ulcerative colitis. However, IFN-induced Crohn’s disease (CD) has previously been reported in only two individuals. We share our own experience of a patient treated for chronic HCV infection who developed CD after IFN therapy for chronic HCV infection. A 28-year-old asymptomatic man with a history only of chronic HCV infection was treated with IFN and ribavirin, which he tolerated for 18 months and achieved sustained viral response (SVR). Halfway through the IFN regimen, he noticed infrequent painful bowel movements and bloody diarrhea. Following treatment, his symptoms resolved. Six months after therapy, colonoscopy showed a normal terminal ileum and colitis with skipped lesions and rectal sparing. Pathology demonstrated spotty chronic active colitis, with diffuse cryptitis, crypt distortion, and abundant abscesses, compatible with CD. The patient declined treatment and remained asymptomatic for two years. Labs including C-​reactive protein (CRP), erythrocyte sedimentation rate (ESR), fecal calprotectin, and celiac panel were normal. Upper GI endoscopy and capsule endoscopy were normal. Repeat colonoscopy showed normal terminal ileum and normal colonic mucosa, and biopsies of the terminal ileum and all segments of the colon were unremarkable. The patient was observed off treatment and has continued to remain asymptomatic, with a resolution of symptoms and disease continuing away from IFN exposure. This is a rare case of CD induced by IFN, exhibiting significant importance regarding the evaluation of new cases of inflammatory bowel disease (IBD). Gastroenterologists need to keep in mind that INF therapy can be an uncommon cause of IBD.