Did the COVID-19 Pandemic Change the Clinical Presentation and Management of Paediatric IgA Vasculitis? A Multicentre Retrospective Cohort Study

Objectives: Immunoglobulin A vasculitis (IgAV) is the most common systemic vasculitis in children and is frequently preceded by a respiratory or gastrointestinal infection. The COVID-19 pandemic affected the epidemiology of infections across multiple paediatric conditions and was accompanied by changes in hospitalization criteria, therapeutic practice, and healthcare organization. The aim of this study was to compare the clinical presentation and treatment of IgAV in children before and after the onset of the COVID-19 pandemic. Methods: We retrospectively analysed the medical records of 160 patients aged 0–18 years who were hospitalized for IgAV between 2015 and 2023 at three paediatric centres in the Lodz region. Patients were divided into two temporal groups: group hospitalized between 2015 and 2020 (n = 82) and group hospitalized between 2021 and 2023 (n = 78). Demographic data, length of hospitalization, disease severity, renal involvement, and treatment were compared between the groups. Results: Patient age did not differ significantly between the groups (7.2 ± 3.82 vs. 6.8 ± 3.55 years; p = 0.469). The mean length of hospitalization decreased from 10.2 ± 4.78 to 7.9 ± 3.18 days (p < 0.001). The proportion of patients classified as having severe IgAV was lower in the 2021–2023 group than in the 2015–2020 group (9.0% vs. 20.7%; p = 0.046). Urinary abnormalities during hospitalization were observed in 16.7% of patients in the 2021–2023 group and in 40.2% of patients in the 2015–2020 group (p < 0.001). After the onset of the pandemic, antibiotics and etamsylate were used significantly less frequently, whereas the frequency of glucocorticoid treatment did not change significantly. Conclusions: Compared with the 2015–2020 period, children hospitalized with IgAV in 2021–2023 had shorter hospital stays, lower CRP concentrations, and less frequent urinary abnormalities, while antibiotics and etamsylate were used less frequently. The proportion of patients classified as having severe disease was also lower, although this difference was attenuated in sensitivity analysis. These temporal differences may reflect changes in infection epidemiology, clinical practice, and healthcare organization after the onset of the COVID-19 pandemic. However, the available data do not allow a direct relationship with SARS-CoV-2 infection to be established.