Simultaneous onset of Crohn's disease and Psoriasis in a Multiple Sclerosis patient treated with Teriflunomide: A novel case report highlighting potential autoimmune interactions.

Teriflunomide (TFN) is an oral Disease-modifying therapy (DMT) widely used in the treatment of relapsing forms of Multiple Sclerosis (MS). Although TFN has demonstrated efficacy in reducing MS activity, recent evidence suggests a possible association between TFN and the onset of rare and severe medical conditions. We present a novel case report of a 47-year-old woman with a history of MS who developed concurrent Crohn's disease and Psoriasis following TFN treatment. This unique occurrence has not been previously documented in the literature. The patient experienced gastrointestinal symptoms and changes in nail color while on TFN. Colonoscopy and biopsy revealed crypt architectural distortion and lamina propria expansion, indicative of Crohn's disease, while dermatological evaluation suggested Psoriasis. Consequently, TFN was discontinued and switched to alternative therapy (Glatiramer acetate), and the patient underwent close observation and regular evaluations. Three months after stopping the TFN, the patient's nail lesions disappeared completely, her abdominal pain and diarrhea were resolved, and the follow-up colonoscopy was completely normal. In this regard, the association between MS, Inflammatory Bowel Disease (IBD), and Psoriasis has been reported in previous studies, with potential involvement of Th17 and IL-17 pathways. Although gastrointestinal side effects with TFN use are typically mild and transient, rare cases of TFN-induced IBD have been reported. Dermatological disorders, including Psoriasis, have also been linked to TFN use, with similarities to our case report. Further research and awareness are warranted to better understand the potential side effects and long-term implications of TFN in the management of MS.