Henoch-Schonlein purpura nephritis (HSP) in children is a clinical syndrome characterized by skin purpura, hemorrhagic gastroenteritis, arthritis and glomerulonephritis. Henoch-Schonlein purpura nephritis is an allergic disease associated with vascular autoimmune damage and with small vessel inflammation as the main lesion. Its basic lesions are IgA deposition in the glomerular mesangial area and mesangial cell proliferation with or without crescent formation. Renal damage often occurs within 3 months of the onset of skin purpura (95%). Although there are reports that renal damage can occur before skin purpura and 1 year after skin purpura, renal damage that occurs after 6 months should generally not be easily regarded as purpuric nephritis. About half of HSP children develop renal damage, which is called anaphy lactoid purpura nephritis.