Demographic and clinical features of pediatric vasculitis: a single-center study.

Introduction: Vasculitides are rare systemic conditions which may occur in childhood. This study aims to document demographic and clinical features of systemic vasculitides in a tertiary center, comparing our outcomes with previously published studies of other international centers.

Methods: Patients presenting with systemic vasculitis before 18 years of age, admitted to a tertiary Portuguese center at diagnosis or during follow-up, from 2009 to 2020, were retrospectively included in this study.

Results: In our study, we included 138 patients. The youngest patients at diagnosis were in the Kawasaki's disease (KD) group, with a median age at diagnosis of 2.26 years old (IQR 1.07-6.20), as opposed to the Behçet's syndrome (BS) group with a median age at diagnosis of 13.41 years old (IQR 10.19-16.75), which was significantly higher (p 90% in both IgA Vasculitis (IgAV) and KD. Gastrointestinal symptoms were common in all groups (15-50%), rarer in BS (17%). Arthritis and arthralgia were highly prevalent in IgAV (65%). The American Heart Association criteria of diagnosis for complete KD were met in 62% of cases. No significant difference was found in age distribution between complete and incomplete diagnosis (p=0.616). Mean duration of fever in KD was 9.6 ±2.1 days, which was higher than anticipated. Renal manifestations in IgAV (11%) and ophthalmic involvement in BS (22%) were lower than expected. There was a notable number of children reporting joint involvement in KD (27%). We also noticed a slightly higher prevalence of vascular events in BS (30%).

Conclusions: Each specific vasculitis assessed had different key symptoms, but there are several complaints and signs shown by our patients, some of them overlapping between vasculitides and others very atypical, such as recurrent epididymitis in BS due to microvasculitis. We can state that most of our findings are in concordance with current literature, with some notable exceptions. Pediatric multicentric population-based studies are warranted to increase research and design clinical trials concerning this field of knowledge.