Raynaud's disease is a rare disorder of the blood vessels, usually in the fingers and toes. It causes the blood vessels to narrow when you are cold or feeling stressed. When this happens, blood can't get to the surface of the skin and the affected areas turn white and blue. When the blood flow returns, the skin turns red and throbs or tingles. In severe cases, loss of blood flow can cause sores or tissue death. Primary Raynaud's happens on its own. The cause is not known. There is also secondary Raynaud's, which is caused by injuries, other diseases, or ceain medicines. People in colder climates are more likely to develop Raynaud's. It is also more common in women, people with a family history, and those over age 30 . It also shows antinuclear antibodies in blood which can be recognised by an ANA test . Ref - Davidson's medicine 23e p1035