Raynaud Syndrome, also known as Raynaud's phenomenon, is a medical condition in which spasm of arteries cause episodes of reduced blood flow. Typically, the fingers, and less commonly the toes, are involved. Rarely, the nose, ears, or lips are affected. The episodes result in the affected part turning white and then blue. Often, there is numbness or pain. As blood flow returns, the area turns red and burns. The episodes typically last minutes, but can last up to several hours. There are two main types: primary Raynaud's, when the cause is unknown, and secondary Raynaud's, which occurs as a result of another condition.