A systemic non-thrombocytopenic purpura caused by HYPERSENSITIVITY VASCULITIS and deposition of IGA-containing IMMUNE COMPLEXES within the blood vessels throughout the body, including those in the kidney (KIDNEY GLOMERULUS). Clinical symptoms include URTICARIA; ERYTHEMA; ARTHRITIS; GASTROINTESTINAL HEMORRHAGE; and renal involvement. Most cases are seen in children after acute upper respiratory infections. The disease is Experimental Factor Ontology identifier EFO_1000965 (Henoch-Schoenlein purpura). Also known as: Allergic purpura, Allergic purpura (disorder), Allergic purpura NOS (disorder), Autoimmune purpura (disorder) [Ambiguous], Henoch-Scholein purpura, Henoch-Schonlein Purpura, Henoch-Schonlein purpura, Henoch-Schonlein purpura (disorder).