Purplish Terminal Ileum: Adult IgA Vasculitis Mimicking Crohn's Disease.

Immunoglobulin A (IgA) vasculitis is a systemic small-vessel vasculitis with frequent gastrointestinal involvement; however, isolated terminal ileitis mimicking Crohn's disease is rare in adults. We report a case of a previously healthy adult patient who presented with acute abdominal pain and bloody diarrhea, with imaging and endoscopic findings suggestive of Crohn's disease. Colonoscopy revealed isolated terminal ileitis with a distinctive purplish cyanotic appearance. The development of palpable purpura and biopsies demonstrating IgA deposition in the skin and ileal tissue confirmed the diagnosis of IgA vasculitis. Recognition of characteristic endoscopic vascular features is critical to avoid misdiagnosis and inappropriate biological therapy.