Definition:

IgA vasculitis (IgAV), also known as Henoch-Schonlein purpura (HSP), is the most common systemic small vessel vasculitis in childhood with clinical characteristics of non-thrombocytopenic palpable purpura, arthritis, and involvement of internal organs such as gastrointestine (GI) and kidney. IgAV has been associated with a history of preceding infections, especially upper respiratory tract infection. In addition, other characteristics of IgAV include the deposition of IgA and C3 in small vessel walls, polymorphonuclear neutrophil infiltration around the vessel and in vessel walls, and increased serum levels of IgA and proinflammatory cytokines at the acute stage. Combined, IgAV is regarded as a specific immune-mediated entity induced by environmental factors, particularly infections. Clinically, since there are no disease-specific laboratory abnormalities, IgAV is currently diagnosed based on symptoms and signs and histopathological findings. Treatment is supportive because IgAV is usually self-limiting except for serious GI or renal involvement.