Severe glomerulonephritis and tubulo-interstitial nephritis accompanied with urticaria and vasculitis

We report a 9-year-old girl who developed recurrent urticaria, arthritis and serious renal involvement. She was treated by prednisolone with considerable improvement. Biopsy examinations revealed cutaneous vasculitis and moderate mesangial proliferation with crescents and tubulo-interstitial nephritis on light microscopy. Immunofluorescence study showed IgG, IgM and complement deposits in the mesangium and along the capillary wall. On electron microscopy, electron-dense deposits were identified in the mesangium and paramesangium. Her disease resembled the hypocomplementemic vasculitis syndrome, but her serum complement values were normal throughout the course of the illness. The pathogenesis of her disease is unknown, but it seems to be a sort of systemic immune-complex disease.