What is the definition or description of: henoch schonlein purpura?

HSP: Henoch-schonlein purpura (hsp) is a type of inflammation of the blood vessels (vasculitis) most often seen in children. It can present with petechiae or purpura on the skin, joint pain, and abdominal pain. Most patients do well and fully recover, but in some cases there can be damage to the kidneys and other organs so close follow up is required.