RHEUMATOLOGY Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP) is the most common vasculitic disease of childhood. It is a multisystem disease most commonly aVecting skin, joints, gastrointestinal tract, and kidneys, but other organs may be aVected. Epidemio-logical studies have shown HSP to have an annual incidence of approximately 13.5–18/ 100 000 children.1 2 Although this is a condition that can occur from age 6 months to adulthood, 50 % of cases occur in children under 5 years of age and 75 % are under 10 years. In most reports HSP is more common in boys.3 The cause remains unknown although there is often an antecedent respiratory infection. Streptococcal infections have been implicate