Definition of Raynaud's phenomenon:

Raynaud' s phenomenon is a condition in which cold temperatures or strong emotions cause blood vessel spasms that block blood flow to the fingers, toes, ears, and nose.

Causes, incidence, and risk factors:

Raynaud's phenomenon can be associated with other conditions. This is called secondary Raynaud's phenomenon. Most people with the condition are over age 30.

Common causes are:

• Diseases of the arteries, such as atherosclerosis and Buerger's disease, which is associated with smoking
• Drugs that cause narrowing of arteries, such as amphetamines, certain types of beta-blockers, some cancer drugs, ergot compounds, and methysergide
• Arthritis and autoimmune conditions, such as scleroderma, Sjogren syndrome, rheumatoid arthritis, and systemic lupus erythematosus
• Repeated injury, particularly from vibrations such as those caused by typing or playing the piano
• Smoking
• Frostbite
• Thoracic outlet syndrome

Raynaud's phenomenon also occurs without another disease, medication, or cause. This is called primary Raynaud's phenomenon. It most often begins in people younger than age 30.