When your body is exposed to cold temperatures, the extremities of your body, such as your fingers and toes, lose heat. This is because the small blood vessels under the skin become narrower, slowing down the blood supply that helps to preserve your body's core temperature.
In people with Raynaud's, the small blood vessels in the fingers and toes are more sensitive than usual and overreact to cold temperatures. This makes them spasm, which means they narrow much more than usual allowing much less blood to flow through them.
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.
It seems that primary Raynaud’s is caused by disruptions in how the nervous system controls blood vessels. Exactly what causes these disruptions is still unclear.
There is some evidence that Primary Raynaud’s may be an inherited condition as cases have been known to run in families.
In some cases, there is an underlying reason, usually a health condition, that causes the blood vessels to overreact. This is called secondary Raynaud's.
The majority of cases of secondary Raynaud’s are associated with what are known as autoimmune conditions. These are conditions where the body defence against infection, the immune system mistakes healthy tissue as a threat to the body. It then sends disease-fighting antibodies to the tissue which can cause a range of symptoms, such as redness and swelling in the affected area.
Autoimmune conditions known to be associated with secondary Raynaud’s 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 body’s sweat and tear glands
lupus: which causes tiredness, joint pain and skin rashes
Around 1 in 10 people with primary Raynaud’s go on to develop an autoimmune condition.
Two blood-born viral infections, hepatitis B and hepatitis C, can occasionally trigger Raynaud’s in some people.
Some types of cancers can cause secondary Raynaud’s. These are usually 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
Secondary Raynaud's can be a side effect of taking certain medicines, including:
The illegal drugs cocaine and amphetamine can also cause secondary Raynaud’s.
Injury and overuse
Raynaud's sometimes results from a physical injury to the affected area. It can also affect musicians, people who type a lot or other people who use their fingers and hands more than usual.
Vibration white finger
Vibration white finger is a term used when secondary Raynaud's has been caused by exposure to vibration. This typically happens to people who regularly use certain types of vibrating tools, including:
- concrete breakers and pokers
- sanders, grinders and disc cutters
- hammer drills
- chipping hammers
- chainsaws, hedge trimmers and power mowers
- scabblers and needle guns
Any vibrating tool that causes tingling or numbness in your fingers after five minutes of continuous use could lead to vibration white finger.
Your employer has a responsibility to protect you from vibration white finger. You can help your employer by asking if the job could be done differently without using vibrating tools. If this is not possible:
- ask to use suitable low-vibration tools
- make sure you are using the right tool for the job
- check tools are properly maintained
- keep cutting 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 tools indoors so they do not have cold handles when next used
- encourage your blood circulation by keeping warm, giving up smoking and massaging and exercising your fingers during your breaks
If you are diagnosed with vibration white finger, tell your employer as soon as possible. If you stop using vibrating tools at an early stage of the condition, 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.
The GOV.UK website has more information about how to apply for an Industrial Injuries Disablement Benefit.