Clinical and laboratory characteristics of pediatric IgA vasculitis (Henoch–Schönlein purpura) – A 15-year retrospective study

ABSTRACT Background: IgA vasculitis (IgAV), formerly Henoch–Schönlein purpura (HSP), is the most common systemic small-vessel vasculitis in children. Its clinical spectrum and regional comorbidities remain incompletely characterized. We aimed to evaluate the epidemiological, clinical, and laboratory features of pediatric IgAV over 15 years in a single center. Materials and Methods: We retrospectively analyzed 800 pediatric patients diagnosed with IgAV at a tertiary hospital in Turkey from 1995 to 2010. All patients met the EULAR/PRINTO/PReS classification criteria for HSP/IgAV. Demographic data, clinical manifestations, laboratory results, treatment, and outcomes (e.g., relapse, complications) were collected from medical records. Inclusion criteria were a definitive diagnosis of IgAV within the study period; cases with incomplete records or alternate diagnoses were excluded. Missing data affected <5% of potential cases and were handled by exclusion to avoid bias. Statistical analyses were performed using SPSS 16.0. Descriptive statistics are presented as mean ± standard deviation or median (minimum–maximum) for continuous variables and as percentages for categorical variables. The Chi-square test was used for categorical comparisons, and the t-test or Mann–Whitney U-test for continuous variables as appropriate. Effect sizes (e.g., odds ratios [ORs]) were calculated for significant comparisons. Results were evaluated at a 95% confidence interval (CI), and a P < 0.05 was considered statistically significant. Results: The cohort’s mean age was 7.5 ± 3.2 years (median 7, range 1–17), with 56% of patients between 6 and 10 years old. Male: female ratio was 1.43:1 (58.9% male, P = 0.26 vs. equal distribution). 54% of cases presented in autumn or winter, significantly more than in spring/summer (46%, P < 0.001, OR = 1.17, 95% CI 1.02–1.34), and 26% had a recent upper respiratory infection. The most frequent clinical features were joint pain (40%) and abdominal pain (38%), followed by skin purpura (present in 100%, classically on the lower limbs) and renal involvement (overall 45%; 34% proteinuria, 11% hematuria). Severe renal involvement was uncommon: 24-h proteinuria was in the nephritic range in 20% of patients and nephrotic range in 14%. Gastrointestinal bleeding (occult blood in stool) occurred in 13%. Only 14% of patients required systemic steroid therapy; the rest were managed supportively. The relapse rate was 8.0% (95% CI: 6.1%–9.9%), and 3.0% of cases had a chronic persistent course. Relapse patients had higher proteinuria rates (OR = 2.3, 95% CI 1.4–3.8, P = 0.002) and hematuria (OR = 1.8, 95% CI 1.1–2.9, P = 0.02) compared to nonrelapse. Overall, 11% of patients experienced at least one serious complication. Notably, 11% of the cohort had co-existing familial Mediterranean fever (FMF). Conclusion: In this large pediatric IgAV cohort, the disease generally had a mild, self-limited course with low relapse and complication rates. Clinical findings reinforced the classic tetrad of purpura, arthritis, abdominal pain, and renal involvement. A striking seasonal clustering in autumn-winter and frequent antecedent infections underscore the role of environmental triggers in IgAV. The observation of an 11% FMF co-occurrence is a unique finding suggesting that genetic and regional factors may influence disease expression. These results expand the understanding of IgAV in childhood and may guide clinicians in prognostication and management of this condition.