What can cause raynaud's phenomenon?

Cold and stress. We do not completely understand the cause of raynaud's, but exposure to cold and emotional stress cause spasm in the blood vessels of the hands and feet. This causes a reduction in blood flow. The lack of oxygen in the area cause the color to change to white, with continued lack of oxygen they turn blue and then red as the spasm resolves and blood flow returns.
Usually cold. Raynauds involves cold or stress induced vasospasm of small vessels in hands and feet. It is really more of an annoyance than a harmful problem. Calcium channel blockers are the most common medication that physicians use to treat the symptoms of raynauds. The main drawback is the side effects from these medicines. Keeping your hands and feet warm remains the best treatment.

Related Questions

Raynaud phenomenon syndrome question. Is it really that or poor circulation?

See below. Raynaud's phenomenon describes a set of color changes in response to cold or stress. These are usually preventable and treatable. Poor circulation does not have those changes. Read more...
Color and location. Raynauds causes fingers to turn either white, blue and/or red usually in the cold. Poor circulation is different because it can affect palms and usually the border of the color change is a smooth transition. Raynauds usually has a distinct line between normal and blue /white. Read more...