Age of onset as a risk factor of renal involvement in Henoch-Schönlein purpura.

Background: Henoch-Schönlein purpura (HSP) is the most common vasculitis in children, characterized by triad of symptoms; palpable purpura without thrombocytopenia, abdominal pain, and arthritis. Renal involvement often occur in children with HSP. No data on the renal involvement of children with HSP in Indonesia, especially West Java.