Immunoglobulin A vasculitis (IgAV), formerly called Henoch-Schönlein purpura, is an abnormal immune system reaction. It causes inflammation and damage to small blood vessels in the skin. This causes a rash, usually in the lower part of the body. The rash looks like bruises or red-purplish spots. It can also affect blood vessels of the joints, intestines, kidneys, and other organs.
This reaction most often affects children. It can also affect adults. The exact cause isn't known. It may be linked with a recent infection from a virus or bacteria. Some kinds of food or medicines may be a factor. The symptoms get better in 4 to 6 weeks. But they may come back during the next 6 months. This isn't a contagious disease. It can't be spread to other people.