Therapeutic success of factor XIII substitution for IgA vasculitis with gastrointestinal manifestation.

A 52-year-old man presented with severe abdominal pain, elevated C-reactive protein (CRP) levels, and characteristic skin findings, leading to a diagnosis of immunoglobulin A (IgA) vasculitis with gastrointestinal (GI) involvement. Initial evaluation, including contrast-enhanced computed tomography (CT) and esophagogastroduodenoscopy (EGD), revealed marked inflammation of the duodenum and a punched-out ulcer, both of which showed partial improvement with conservative treatment. However, the patient developed worsening abdominal pain, arthralgia, and purpura, accompanied by reduced plasma factor XIII activity (47%). Factor XIII substitution therapy was initiated as a monotherapy, resulting in immediate symptom relief and significant endoscopic improvement of the duodenal ulcer. This case highlights the potential of factor XIII monotherapy as an effective treatment option for adult IgA vasculitis with severe GI manifestations.