What causes Raynaud's?

Raynaud's phenomenon occurs when the small blood vessels within the body's extremities, such as the fingers and toes, are over-sensitive. This oversensitivity causes a more extreme reaction in response to certain triggers, such as cold weather. This is known as a Raynaud's attack.

Primary Raynaud's

This is the milder and most common form of Raynaud's phenomenon. In primary Raynaud's the condition occurs by itself, and is not associated with any other health issues. It is likely that primary Raynaud's is caused by certain disruptions to the way that the nervous system controls blood vessels, although exactly what causes these disruptions remains unknown. What we do know is that the attacks themselves can be triggered by changes in temperature, emotional changes, stress, hormones or in some cases by using certain vibrating tools.

When we are exposed to the cold, a normal response is for the blood vessels, including those in the fingers and toes, to become narrower, or constrict. When someone has Raynaud's, this constriction of the blood vessels is more extreme, which can be very uncomfortable and may result in the skin changing colour, from white to blue and then to red. This process can be quite painful, especially as blood vessels return to normal and the circulation returns. Raynaud's can also affect the lips, nose, ears and nipples in the same way.

There is evidence that primary Raynaud's may sometimes be an inherited condition, since multiple cases can arise within the same family. Raynaud's is not contagious and cannot be passed on to others. Many people will never know what caused them to develop Raynaud's, although it may sometimes be linked to other underlying health conditions.

Who is likely to develop Raynaud's?

Primary Raynaud's is more common in young women and girls, although both forms of the condition can affect men, women and children of any age. Many people with Raynaud's have never actually seen a doctor about their symptoms. If you or someone you know suffers from cold hands or feet regularly, it is always worth talking to your doctor. There are excellent treatments that can relieve the unpleasant symptoms of Raynaud's attacks. It is also important that any associated conditions that may have caused secondary Raynaud's to develop are ruled out.

Secondary Raynaud's

In some cases, it is another health condition that causes the blood vessels to overreact, leading to Raynaud's symptoms. This is called secondary Raynaud's. The chances of having secondary Raynaud's are very low, since only 10% of people with Raynaud's will develop an associated condition.

Most cases of secondary Raynaud's are linked to autoimmune diseases, meaning that the immune system is overactive, causing it to attack healthy tissues within the body.

Scleroderma is one example of an autoimmune condition that is known to be associated with secondary Raynaud's, however there are a number of other possibilities, including:

  • rheumatoid arthritis – which causes joint pain and swelling
  • Sjogren's syndrome – where the immune system affects the body's sweat and tear glands
  • lupus – which causes tiredness, joint pain and skin rashes
  • Diseases affecting the arteries, including atherosclerosis, meaning the build-up of plaques within the blood vessels that feed the heart; or Buerger's disease, a disorder wherby the blood vessels of the hands and feet become inflamed. Primary pulmonary hypertension is a type of high blood pressure that can also be linked to Raynaud's
  • Carpal tunnel syndrome which involves pressure upon a major nerve to the hand (the median nerve). This causes numbness and pain, which may then make the hand more susceptible to cold temperatures and episodes of Raynaud's
  • Repetitive action or vibration, which may arise from typing, playing the piano or doing similar movements for long periods of time. Using vibrating tools such as jackhammers is also known to increase the risk of developing Raynaud's
  • Smoking is a factor in developing Raynaud's as this constricts the blood vessels
  • Injuries to the hands or feet, such as a wrist fracture, surgery or frostbite can all lead to Raynaud's phenomenon
  • Certain medications including beta blockers used to treat high blood pressure, migraine medications containing ergotamine or sumatriptan, medications for attention-deficit/hyperactivity disorder, certain chemotherapy agents and other drugs that cause blood vessels to narrow have also been linked to Raynaud's