Causes of Raynaud's

Raynaud's phenomenon is the result of over-sensitive blood vessels in the body's extremities. In many cases, no cause is identified, although it's sometimes linked to other health conditions.

When your body is exposed to cold temperatures, the extremities, such as your fingers and toes, lose heat. This is because the small blood vessels under the skin spasm, slowing down the blood supply that is helping to preserve your body's core temperature.

In people with Raynaud's, the sensitive blood vessels overreact to cold temperatures and become narrower than usual, significantly restricting the blood flow.

Symptoms can be triggered by mildly cool weather, getting something out of the freezer, or running your hands under a cold tap. Strong emotions such as stress or anxiety may also trigger symptoms.

Primary Raynauds

The most common form of Raynaud's is primary Raynaud's phenomenon. This means the condition occurs by itself, without being associated with another health condition.

It seems thatprimary Raynauds is caused by disruptions in how the nervous system controls blood vessels. Exactly what causes these disruptions is unclear.

There's some evidence that primary Raynauds may be an inherited condition, as cases have been known to run in families.

Secondary Raynaud's

In some cases, an underlyinghealth condition couldbe causing the blood vessels to overreact. This is called secondary Raynaud's.

Autoimmune conditions

The majority of cases of secondary Raynauds are associated with autoimmune conditions, which cause the immune system to attack healthy tissue.

Autoimmune conditions known to be associated with secondary Raynauds include:

• Scleroderma a condition that causes hardening and thickening of the skin
• rheumatoid arthritis which causes joint pain and swelling
• Sjogren's syndrome where the immune system attacks the bodys sweat and tear glands
• lupus which causes tiredness, joint pain and skin rashes

Around1 in 10 people with primary Raynauds go on to develop an autoimmune condition.

Infections

Blood-born viral infections, hepatitis B and hepatitis C , can occasionally trigger Raynauds in some people.

Cancer

Some types of cancer can cause secondary Raynauds. These areusually cancers that develop inside the blood, bone marrow or immune system, such as:

• acute lymphoblastic leukaemia a cancer of the white blood cells that mainly affects children
• lymphoma a cancer that develops inside one or more of the glands that are part of the immune system
• multiple myeloma a cancer that develops inside bone marrow

Medicines

Secondary Raynaud's can also be a side effect of taking certain medicines, including:

• some types of anti- migraine medication such as sumatriptan and ergotamine
• beta-blockers which are used to treat high blood pressure and heart disease
• some chemotherapy medicines
• decongestants
• the contraceptive pill
• medicines used in hormone replacement therapy
• some types of medicines usedto treathigh blood pressure such as angiotensin-converting enzyme (ACE) inhibitors and clonidine

Illegal drugs , such as cocaine and amphetamines, can also cause secondary Raynauds.

Injury and overuse

Raynaud's sometimes results from a physical injury. It can also affect musicians, people who type a lot, or other people who use their fingers and hands more than usual.

Skin and tissue damage caused by frostbite can also lead to Raynaud's.

Smoking

Smoking cigarettes also increases your risk of developing Raynaud's. Readabout the support available to help you quit smoking .

Vibration white finger

Vibration white finger is a term used when secondary Raynaud's has been caused by vibration. This typically happens to people who regularly use certain types of vibrating tools, such as:

• sanders, grinders and disc cutters
• hammer drills
• chainsaws, hedge trimmers and power mowers

Any vibrating tool that causes tingling or numbness in your fingers could lead to vibration white finger.

Your employer has a responsibility to protect you from vibration white finger. If the job can't be done without vibrating tools:

• ask to use suitable low-vibration tools
• make sure you're using the right tool for the job
• check tools are properly maintained
• keepcutting tools sharp
• reduce the amount of time you use the tool in one go by doing other jobs in between
• keep warm at work
• wear anti-vibration gloves
• store toolsindoors, so they don't have cold handles when next used
• encourage your blood circulation by keeping warm, stopping smoking and massaging and exercising your fingers during your breaks

If you're diagnosed with the condition, tell your employer as soon as possible. If you stop using vibrating tools at an early stage, you may recover fully.

By law, your employer must contact the Health and Safety Executive about your condition. You may be entitled to an Industrial Injuries Disablement Benefit, which is a payment given to people who have become ill or injured as a result of their work.

See the GOV.UK website for more information about the Industrial Injuries Disablement Benefit .