Henoch-Schönlein purpura nephritis.

Henoch-Schönlein purpura (HSP) is a systemic vasculitic disorder first reported by Heberden in 1806. The association of purpura and joint pain was described by Schönlein in 1837, who termed it “peliosis rheumatica.” Henoch added a description of four children with skin lesions associated with colicky abdominal pain, gastrointestinal hemorrhage, and joint pain in 1874, and in 1899 pointed out that renal involvement sometimes occurred. Synonyms include anaphylactoid purpura, allergic vasculitis, leukocytoclastic vasculitis, and rheumatoid purpura. It is a multisystem disorder mainly affecting the skin, joints, gastrointestinal tract, and kidneys but sometimes other organs. It has been suggested that IgA nephropathy, first described by Berger and Hinglais, and HSP represent a spectrum of clinical presentations of the same or a similar disorder, the former lacking the clinical manifestations in extrarenal organs seen in the latter.