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.