Abstract

Henoch-Schönlein purpura (HSP), or immunoglobulin A (IgA) vasculitis, is the most common small-vessel vasculitis in childhood, and renal involvement and disease recurrence are the main determinants of long-term outcome. This study aimed to evaluate the clinical and laboratory characteristics of children with HSP and to identify factors associated with renal involvement and disease recurrence. This single-center retrospective study included children aged 1-18 years diagnosed with HSP between January 2018 and June 2025 according to the EULAR/PRINTO/PRES criteria. Demographic, clinical, and laboratory data at diagnosis were extracted from medical records. Renal involvement was defined as the presence of microscopic hematuria and/or proteinuria. Disease recurrence was defined as reappearance of HSP manifestations after a symptom-free period of at least four weeks. A total of 102 children (66.7% male, mean age 8.0 ± 2.9 years) were included. Renal involvement was detected in 32 patients (31.4%), and recurrence occurred in 10 patients (9.8%). Hemoglobin levels were significantly lower in patients with renal involvement compared with those without (12.7 ± 1.2 vs 13.4 ± 1.4 g/dL, p=0.012), while C-reactive protein (CRP) levels were higher, although not reaching statistical significance (2.6 ± 3.2 vs 1.4 ± 1.7 mg/L, p=0.053). CRP showed limited ability to discriminate renal involvement (AUC=0.62). No clinical or laboratory parameter independently predicted disease recurrence in multivariate analysis. Renal involvement occurred in approximately one-third of children with HSP and was associated with lower hemoglobin levels and higher CRP values, reflecting increased inflammatory burden. However, CRP demonstrated limited predictive value, and no single laboratory marker reliably predicted renal involvement or recurrence. Children with systemic involvement may benefit from closer follow-up, and larger prospective studies are needed to develop more accurate predictive models.

Key words: Henoch-schönlein purpura, iga vasculitis, renal involvement, recurrence, children, c-reactive protein