Inflammation of the blood vessels (vasculitis) may be caused when antibodies that have attached to antigens in the blood (immune complexes), attach to the blood vessel walls. These purplish spots can be felt in the skin. They do not turn white (blanch) when pressed. As the condition progresses, they may become larger and more bruise-like (ecchymotic), and some may develop central ulceration or necrosis (tissue death).
Review Date: 4/28/2006
Reviewed By: Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.