What Causes Raynaud's?

When the body is subjected to cold or emergency conditions, the muscles in the walls of the arteries supplying the skin, hands and feet contract to reduce the blood flow, thus ensuring that the core tissues and organs receive correspondingly higher amounts of warm, oxygenated blood. This nervous reaction is much more easily triggered in Raynaud's patients, so that a relatively small amount of cold can result in arteries narrowing (known as vasospasm), temporarily cutting off some of the blood supply to the toes or fingers. Strong emotion, such as anxiety, may also trigger symptoms. Over time, these small arteries may also thicken slightly, further limiting blood flow.

Raynaud's may be caused by damaged arteries, sensitivity to substances such as tobacco, other general circulatory disorders, emotional crisis or disorders of the endocrine or nervous system. The commonest immediate cause is cold.