Gastrointestinal features of pediatric iga vasculitis and their association with renal complications: an...

Immunoglobulin A (IgA) vasculitis is the most common systemic vasculitis in childhood, primarily affecting the skin, gastrointestinal system (GIS), joints, and kidneys. This study aimed to evaluate the clinical and laboratory characteristics of mild and severe GIS involvement in pediatric patients with IgA vasculitis and to investigate its association with renal involvement. A retrospective review was conducted on 794 pediatric patients diagnosed with IgA vasculitis between 1997 and 2024. Demographic data, clinical findings, and laboratory parameters were collected from patient records. GIS involvement was classified as mild (abdominal pain, vomiting, or occult blood in stool) or severe (melena, hematochezia, or intussusception). Renal involvement was defined based on hematuria, proteinuria, hypertension, or renal insufficiency. Among 794 patients, 430 (54.2%) were male, with a mean age at diagnosis of 7.8 ± 3.3 years. GIS involvement was observed in 422 (53.1%) patients, of whom 333 (78.9%) had mild GIS involvement and 89 (21.1%) had severe GIS involvement. Renal involvement was detected in 171 (21.5%) patients, and was more frequent in those with GIS involvement (26.3% vs. 16.1%, p = 0.001). GIS (55.6% (n = 306) vs. 47.1% (n = 115)) and renal (24.5% (n = 134) vs. 15.2% (n = 37)) involvement were more common in patients aged > 5 years than in patients ≤ 5 years (p = 0.027, p = 0.004, respectively). GIS involvement was significantly associated with leukocytosis (p < 0.001) and elevated C-reactive protein (CRP) (p = 0.018), but these parameters did not correlate with renal involvement. Patients with positive fecal occult blood tests had a significantly higher risk of renal involvement (p < 0.001). However, there was no significant difference in renal involvement between patients with mild and severe GIS involvement (p = 0.082).

GIS involvement, older age (> 5 years), and the presence of occult blood in stool were associated with a higher likelihood of renal involvement in pediatric IgA vasculitis. However, the severity of GIS involvement did not correlate with renal involvement, suggesting that renal pathology may be influenced by independent mechanisms rather than the severity of GIS symptoms.

• Older age, persistent palpable purpura, abdominal pain, GIS involvement, recurrent disease episodes are risk factors for renal involvement in IgA vasculitis.

• GIS involvement, fecal occult blood positivity, and age over five years were significantly associated with renal involvement in pediatric IgA vasculitis. However, the severity of GIS involvement did not predict the presence or severity of renal involvement.