Renal biopsy 2-9 years after Henoch Schönlein purpura.

Twelve children and adolescents with classical Henoch-Schönlein purpura (HSP) underwent renal biopsy 2-9 years later. The clinical course was favorable in 10 of the patients who received only supportive treatment. Two patients with a prolonged course, characterized by marked hematuria and proteinuria, were given steroids and azathioprine first and mycophenolate mofetil later. At the time of biopsy, 4 patients did not have any urinary abnormalities, 6 had hematuria and/or mild proteinuria, and 2 had proteinuria >1 g/24 h. Renal histology showed mild lesions on light microscopy. Immunohistochemistry disclosed mesangial IgA in 8 of the 12 patients. In percentages, this is a proportion of 66.6 with 95% exact confidence limits of 34.9-90.1. In this small series of selected former HSP patients, the majority had IgA nephropathy years after the initial vasculitis episode. This indicates that some patients with apparently completely healed HSP have a chronic glomerular condition that possibly means protracted disease and certainly indicates the need for careful follow-up.