Raynaud phenomenon is a condition that affects your blood vessels (the tubes that your blood flows through). It causes your blood vessels to narrow, which decreases blood flow. This is called a Raynaud episode or "attack." The attacks usually affect your fingers and toes, causing them to become cold and numb. They may also change color, usually to white or blue. These attacks happen in response to cold temperatures or stress.

Raynaud phenomenon may also be called Raynaud disease or Raynaud syndrome.

There are two types of Raynaud phenomenon:

• Primary Raynaud phenomenon is the more common type. Its cause is unknown.
• Secondary Raynaud phenomenon is usually caused by another disease or problem, such as lupus or scleroderma. Other causes may be exposure to cold or certain chemicals. The type can be more serious than the primary type.

Researchers don't know exactly why some people develop Raynaud phenomenon. But they do understand how the attacks happen. When you are exposed to cold, your body tries to slow the loss of heat and maintain its temperature. To do this, the blood vessels in the top layer of your skin constrict (narrow). This moves blood from those vessels near the surface to vessels deeper in the body. But when you have Raynaud phenomenon, the blood vessels in your hands and feet react to cold or stress by narrowing quickly. They also stay narrowed for a long time.

Anyone can develop Raynaud phenomenon, but some people are more likely to develop it:

• Primary Raynaud phenomenon has been linked to:
  • Your sex. Women get it more often than men.
  • Your age. It usually develops in people younger than age 30. It often starts in the teenage years.
  • A family history of Raynaud phenomenon. You are more likely to develop Raynaud phenomenon if you have a family member who has it.
• Secondary Raynaud phenomenon has been linked to:
  • Certain diseases. These include lupus, scleroderma, rheumatoid arthritis (RA), carpal tunnel syndrome, and connective tissue disorders.
  • Certain medicines. Medicines that treat high blood pressure, migraines, and attention deficit hyperactivity disorder (ADHD) may cause similar symptoms to Raynaud phenomenon or make your symptoms worse.
  • Work-related exposures, such as repeated use of vibrating machinery (such as a jackhammer), or exposure to cold or certain chemicals.

Raynaud attacks most often happen when you get cold, for example when you grab something cold from the freezer or go into an air-conditioned building on a warm day. Attacks usually affect your fingers and toes. But sometimes they can affect other parts of your body, such as your ears, nose, lips, or nipples.

An attack causes the skin to become cold and numb. Your skin may also turn white or blue due to a lack of oxygen. As the blood flow returns, your skin may tingle, throb, or turn red. An attack may last a few minutes or a few hours. If you have darker skin, you may not be able to easily see the skin color changes.

For many people, especially those with the primary type, the symptoms are mild. People with the secondary type often have more severe symptoms. They may develop skin ulcers (open sores caused by poor blood flow) or skin infections.

There is no specific test to diagnose Raynaud phenomenon. To find out if you have it, your health care provider:

• Will take your medical history and ask about your symptoms.
• Will do a physical exam.
• May order blood and other lab tests to check for other conditions which could be causing your symptoms and/or to help decide which type of Raynaud phenomenon you have.

Most people with Raynaud phenomenon can keep their symptoms under control by avoiding getting cold. But if this is not enough, medicines and, in some cases, surgical procedures can help.

Secondary Raynaud phenomenon is more likely to be serious and to need more treatments. It's also important to treat the condition or problem that is causing your Raynaud phenomenon.

You may need to see a specialist such as a rheumatologist, a doctor who treats diseases of the joints, muscles, and bones.

Raynaud phenomenon cannot be prevented, but you can help prevent attacks and manage your symptoms by:

• Placing your hands or feet in a warm place when you have an attack. This could mean putting them under warm (not hot) water or under a heating pad.
• Keeping your body, especially your hands and feet, warm in cold weather.
• Avoiding triggers, such as certain medicines and stress.
• Quitting smoking (or not starting smoking).
• Managing stress.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases