Incidence of vasculitis in children in the Czech Republic: 2-year prospective epidemiology survey.

OBJECTIVE: To determine the incidence and presenting features of primary and secondary vasculitides in children across the Czech Republic.

METHODS: The population of 2.02 million children under 17 years of age was surveyed over 2 years. Cases were identified through monthly questionnaires posted to consultant pediatricians in all hospital pediatric departments in the country. Patients were included in the analysis if they met established inclusion criteria for each diagnosis and had disease onset between 1997 and 1999. Incidence rates were calculated from population rates derived from the 1991 Census.

RESULTS: We identified 452 new cases of vasculitis and connective tissue disease. The estimated annual incidence of Henoch-Schonlein purpura (HSP) was 10.2/100,000 children, with a mean age at onset of 7 years. At disease onset palpable purpura was present in all cases; arthritis/arthralgia in 52%; abdominal pain and/or gastrointestinal bleeding in 40%; hematuria/proteinuria in 15%; and genital involvement in 2.8%. Forty-nine percent of all patients with HSP received short term corticosteroids. The estimated annual incidence of Kawasaki disease (KD) was 1.6/100,000 children under 5 years. Thirteen percent of patients with KD had transient dilatation of coronary arteries; 75% received high dose intravenous immunoglobulin. Other primary systemic vasculitides were extremely rare in this population. Secondary vasculitides of connective tissue diseases had an estimated annual incidence of 0.22/100,000 for systemic lupus erythematosus and 0.19/100,000 for dermatomyositis.

CONCLUSION: We determined the incidence of different childhood vasculitides within a hospital based population throughout the Czech Republic. HSP was the most common, with a relatively high proportion of the patients treated with a short course of corticosteroids. A lower incidence than expected of KD raised the suspicion that some cases were not identified. Other childhood vasculitides were rare.