Constriction of small arteries causes fingers (or toes) to become pale or bluish, numb, and tingle.
Doctors can often make a diagnosis on the basis of the person’s symptoms.
Keeping warm, avoiding smoking, and sometimes taking drugs may help.
Raynaud syndrome may be
Primary, meaning no cause is apparent (also called Raynaud disease)
Secondary, meaning an underlying disorder can be identified (also called Raynaud phenomenon)
Doctors use the term Raynaud syndrome to refer to either.
Primary Raynaud syndrome
Primary Raynaud syndrome is much more common then secondary Raynaud syndrome. Between 60% and 90% of cases of primary Raynaud syndrome occur in women aged 15 to 40 years.
Anything that stimulates the sympathetic division of the autonomic nervous system Overview of the Autonomic Nervous System The autonomic nervous system regulates certain body processes, such as blood pressure and the rate of breathing. This system works automatically (autonomously), without a person’s conscious... read more 
, particularly exposure to cold but also strong emotion, can cause arteries to constrict and thus trigger primary Raynaud syndrome.
Secondary Raynaud syndrome
Secondary Raynaud syndrome may occur in people with
Cryoglobulinemia (see )
Injury
Reactions to certain drugs or medications, such as beta-blockers, clonidine, and the antimigraine drugs ergotamine and methysergide
Use of drugs or medications that constrict blood vessels can also make Raynaud syndrome worse.
Some people with Raynaud syndrome also have other disorders that occur when arteries are prone to constrict. These disorders include migraines Migraines A migraine headache is typically a pulsating or throbbing pain that ranges from moderate to severe. It can affect one or both sides of the head. It is often worsened by physical activity, light... read more , variant angina Classification Angina is temporary chest pain or a sensation of pressure that occurs while the heart muscle is not receiving enough oxygen. A person with angina usually has discomfort or pressure beneath the... read more (chest pain that occurs while at rest), and high blood pressure in the lungs (pulmonary hypertension Pulmonary Hypertension ). The association of Raynaud syndrome with these disorders suggests that the cause of arterial constriction may be the same in all of them.
Symptoms of Raynaud Syndrome
Constriction of small arteries in the fingers and toes begins quickly, most often triggered by exposure to cold. It may last minutes or hours. The fingers and toes become pale (pallor) or bluish (cyanosis), usually in patches. Only one finger or toe or parts of one or more may be affected. Numbness, tingling, a pins-and-needles sensation, and a burning sensation in the fingers or toes are common. As the episode ends, the affected areas may be redder than usual or bluish. Rewarming the hands or feet restores normal color and sensation.
If episodes of Raynaud syndrome recur and are prolonged (especially in people with systemic sclerosis Systemic Sclerosis Systemic sclerosis is a rare, chronic autoimmune connective tissue disorder characterized by degenerative changes and scarring in the skin, joints, and internal organs and by blood vessel abnormalities... read more 
), the skin of the fingers or toes may become smooth, shiny, and tight. Small painful sores may appear on the tips of the fingers or toes.
Lighter areas (pallor) are caused by absence of blood flow due to narrowing of blood vessels. The white areas develop irregularly in the fingers.
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The blue areas (cyanosis) at the tips of the fingers are caused by decreased oxygen in the blood because of sluggish blood flow due to partial narrowing of the blood vessels.
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This person with systemic sclerosis has sores and blue fingertips (cyanosis) due to Raynaud syndrome.
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Diagnosis of Raynaud Syndrome
A doctor's evaluation
Sometimes Doppler ultrasonography
Usually, doctors suspect Raynaud syndrome on the basis of symptoms and results of the physical examination. Often, no procedures are needed to make the diagnosis.
If doctors suspect an artery is blocked, Doppler ultrasonography Echocardiography and Other Ultrasound Procedures 
may be done before and after the person is exposed to cold. In people with Raynaud syndrome, blood flow and vessel diameter decrease more than in people without the disorder.
Doctors may also order blood tests to check for conditions that sometimes occur in people with Raynaud syndrome.
Treatment of Raynaud Syndrome
Avoiding triggers such as cold and stress
Smoking cessation
Medications
People can control mild Raynaud syndrome by protecting their head, trunk, arms, and legs from cold. For those who experience symptoms when they get excited, mild sedatives or biofeedback may help. People who have the disorder must stop smoking Smoking Cessation Most people who smoke want to quit and have tried doing so with limited success. Effective tools to help quit smoking include counseling, nicotine replacement products, and medications. While... read more because nicotine constricts blood vessels.
Primary Raynaud syndrome is commonly treated with a calcium channel blocker Calcium channel blockers High blood pressure is very common. It often does not cause symptoms; however, high blood pressure can increase the risk of stroke, heart attack, and heart failure. Therefore, it is important... read more , such as nifedipine or amlodipine. Prazosin may also be effective.
For people with secondary Raynaud syndrome, doctors treat the associated disorder.
Sympathectomy, a procedure in which certain sympathetic nerves Overview of the Autonomic Nervous System The autonomic nervous system regulates certain body processes, such as blood pressure and the rate of breathing. This system works automatically (autonomously), without a person’s conscious... read more that run up and down along the spine may be temporarily blocked (by injection of a medication such as lidocaine) or even cut, may be used to relieve the symptoms of Raynaud syndrome if the disorder becomes progressively disabling and other treatments do not work. However, even when this procedure is effective, relief may last only 1 to 2 years. This procedure is usually more effective for people with primary Raynaud syndrome than for those with secondary Raynaud syndrome.
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
American College of Rheumatology: Raynaud’s Phenomenon: Information on symptoms and triggers and tips people living with Raynaud phenomenon
Raynaud's Association: Provides information and awareness about Raynaud phenomenon and support for people living with it
Vascular Cures: Raynaud's Disease: General information on symptoms, risk factors, diagnosis, and treatment of Raynaud syndrome
