Henoch Schonlein purpura is thought to be due to a type III immune complex mediated hypersensitivity reaction. There is a strong history of atopy in one third of patients. IgA is deposited in the mesangium of the kidney and in the vasculitic lesions in the skin.
It has been suggested that HSP and Berger's disease - IgA nephropathy - may be different presentations of the same disorder in IgA handling.
Last reviewed 01/2018