Ustekinumab-Induced Vasculitis in a Patient With Crohn's Disease

Immunoglobulin A vasculitis (IgAV) is an immune-mediated disorder that commonly involves dermatologic, musculoskeletal, renal, and gastrointestinal systems. Drug-induced cases of IgAV are rare and sparsely documented in the literature. We report a case of a patient with Crohn's disease who developed a tender, palpable purpuric rash on the torso and extremities 3 weeks after receiving a dose of ustekinumab. This case underscores the importance of considering IgAV in patients with inflammatory bowel disease who present with cutaneous symptoms while undergoing treatment with advanced therapies.