Immunoglobulin A vasculitis associated with inflammatory bowel disease: a retrospective cohort study

Objective: To describe the baseline characteristics and outcome of a series of patients with inflammatory bowel disease (IBD) and immunoglobulin A vasculitis (IgAV). Method: Patients with biopsy-proven IgAV with IBD were identified retrospectively. Data were abstracted from direct medical chart review. Each IBD-IgAV case was matched to two controls with IgAV but without IBD. Results: Nine patients were identified (seven Crohn's disease, two ulcerative colitis). Mean length of time between IBD diagnosis and IgAV onset was 17.3 ± 19.9 years. For patients on biologic treatment for IBD, mean length of time between biologic initiation and IgAV onset was 3.3 ± 3.8 years. Active IBD at IgAV onset was present in 56%. Tumour necrosis factor inhibitors (TNFi) were used for IBD in 89%. At IgAV onset, six patients were on treatment with TNFi; one subsequently discontinued, two switched to another TNFi, and three continued. At the last follow-up, three of five patients who remained on TNFi had full resolution of IgAV despite ongoing TNFi use. No differences were seen between cases with IBD IgAV and matched non-IBD-IgAV controls regarding development of end-stage renal disease, resolution of haematuria or proteinuria, and time to complete IgAV response. Conclusion: Baseline characteristics and outcomes of patients with IBD-IgAV are similar to those with IgAV without IBD. Development of IgAV is not limited to patients with clinically active IBD. Whether TNFi use is related to the pathogenesis of IgAV in some patients with IBD remains unclear. Further research into pathophysiological connections between IBD and IgAV is needed.