A Simple Metric for Activity: The Number of Affected Skin Regions in Pediatric IgA Vasculitis

Abstract

Objective: Immunoglobulin A vasculitis (IgAV) is the most common systemic vasculitis in children. While skin manifestations are mandatory for diagnosis, the relationship between the extent of skin involvement and disease activity has not been clearly defined. This study aimed to evaluate the association between the number of skin regions involved and disease activity in pediatric IgAV. Materials and Methods: This retrospective study included 65 children diagnosed with IgAV between January 2024 and September 2025 in a pediatric rheumatology center. Demographic, clinical, and laboratory data were collected from medical records. Disease activity was assessed using the Pediatric Vasculitis Activity Score (PVAS). The extent of skin involvement was quantified as the number of affected anatomical regions (range: 1–5; lower extremities, upper extremities, gluteal region, trunk, and face). Correlation analyses were performed to assess the relationships between the extent of skin involvement, age at diagnosis, PVAS, and inflammatory markers. Results: The mean age at diagnosis among our patients was 9.4±3.5 years, and 55.4% of the patients were male. A significant positive correlation was observed between the number of skin regions involved and both PVAS and age at diagnosis (r=0.277, p=0.026 and r=0.246, p=0.048), while no significant correlation was found with C-reactive protein or erythrocyte sedimentation rate. Conclusion: Assessing the number of affected skin regions may serve as a simple, rapid, and accessible supportive clinical parameter for estimating acute disease activity during the initial evaluation of pediatric IgAV.