Poster Session II - A223 ACQUIRED HEMOPHILIA A IN AN ADOLESCENT WITH ULCERATIVE COLITIS ON INFLIXIMAB: A CASE REPORT

Abstract Background Acquired hemophilia A (AHA) has never been reported in patients with pediatric inflammatory bowel disease (IBD). Aims We describe a case of AHA occurring in an adolescent with ulcerative colitis treated with infliximab. We hypothesize that in rare circumstances, anti-TNF therapy can trigger factor VIII inhibitor development in patients with IBD. Methods We reviewed the disease course of an adolescent with ulcerative colitis who developed AHA after 3 years of infliximab therapy. A focused literature review was performed to assess reports of inflammatory bowel disease and AHA. Results The patient presented at 14 years of age with a 3-month history of bloody diarrhea and raised serum and fecal biomarkers. His colonoscopy showed a Mayo 2 pancolitis. After a course of oral prednisone, he was commenced on infliximab monotherapy in September 2022. He achieved sustained clinical remission with normal serum and fecal biomarkers. Repeat scope in July 2024 showed endoscopic and histologic remission. Intestinal ultrasound in July 2025 showed transmural remission. In July 2025, he presented with spontaneous bruising and palpable purpura on his legs. Laboratory investigations revealed a prolonged aPTT, factor VIII activity