Clinical features and risk factors of abdominal IgA vasculitis in adults.

Background: Adult-onset abdominal IgA vasculitis (A-IgAV) presents with abdominal pain as the initial symptom, which is a relatively rare condition that is frequently misdiagnosed.

Methods: This retrospective study utilized clinical data from 125 adult patients diagnosed with IgA vasculitis (IgAV), retrieved from the electronic medical records of the First College of Clinical Medical Science, China Three Gorges University. The study comprehensively investigated the clinical manifestations, evaluated the diagnostic significance of various laboratory markers, and identified features from abdominal CT and endoscopy.

Results: Of the 125 cases analyzed, 42 involved gastrointestinal (GI) complications, while the remaining 83 did not. A-IgAV predominantly affected younger male patients, with a median age of 37, whereas non-abdominal IgA vasculitis (NA-IgAV) was more common in middle-aged women, with a median age of 47. Patients with purpuric lesions affecting two or more areas of the body were statistically more likely to develop GI complications. Elevated white blood cell (WBC) and C-reactive protein/albumin ratio (CAR) levels, along with reduced immunoglobulin M (IgM), were found to be strong predictors of GI complications, offering substantial prognostic value when WBC exceeded 10.340 × 10⁹/L or CAR surpassed 0.355. Imaging and endoscopy identified the duodenum and ileum as the most commonly affected sites. Endoscopic evaluations frequently revealed mucosal erosion, ecchymosis, ulceration, or hemorrhage, while abdominal CT scans often showed thickening of the intestinal wall.

Conclusions: The duodenum is the most frequently affected site, followed by the ileum and jejunum. Multi-regional purpura, leukocytosis, or elevated CAR are independent risk factors for GI involvement. Key Points • The duodenum is the most predominantly involved site, followed by the ileum and jejunum. • Purpura affecting two or more regions significantly increased the likelihood of GI involvement. • WBC and CAR were identifed as risk factors, while IgM was identified as a protective factor.