Causes and risks of melanoma

The main risk factor for melanoma is exposure to ultra violet (UV) light, through natural sunlight or artificially from sunbeds or lamps. UV light damages the DNA (genetic material) in our skin cells and can cause skin cancers like melanoma.

Sun exposure is not the cause of all melanomas because some melanomas affect parts of the body that aren’t exposed to the sun.

• Ultraviolet (UV) rays from the sun In the UK the number of people developing melanoma and other skin cancers is steadily rising. This may be because people take sunshine holidays abroad more often.

• Ultraviolet light from sunbeds Sunbeds give off artificial UV rays which damage the DNA, increasing the risk of developing melanoma. The more you use a sunbed or lamp the greater your risk. Getting a sunbed tan before you go on holiday can actually increase your risk of melanoma.

It’s important for us all to be aware of the damage that too much exposure to the sun can cause. Some sunshine is good for us. It helps us make vitamin D which keeps bones and teeth healthy, and generally makes us feel better. But it’s important to be aware of the damage that too much exposure to the sun can cause.

If you’ve had a melanoma (or any skin cancer) or are at increased risk of melanoma, it’s essential to protect yourself from the sun.

Other factors that can increase your risk

Your skin type People with fair skin, red or fair hair, blue eyes, and freckles are more sensitive to the sun. Because of their skin type they burn more easily and so are more at risk of getting melanoma. Having brown or black skin lowers your risk of getting melanoma, but it doesn’t mean that you will never get one.

Sunburn Episodes of severe sunburn, especially during childhood, can increase the risk of melanoma in the future.

Having lots of moles and unusual moles People who have a lot of moles (especially over 100) have a higher risk of getting melanoma. People with moles which are bigger than usual, with an irregular shape or colour (called atypical), have an increased risk. These moles (sometimes called dysplastic naevi) rarely change into melanoma, but it’s important to keep an eye on them. Having lots of moles and atypical moles can run in some families. Having a very large (more than 20cm in diameter) dark hairy mole which you were born with also increases your risk of melanoma.

If you have any of the above you can be referred to a skin specialist for advice and an assessment of your skin.

Family history of melanoma This increases your risk, especially if you have two or more close relatives who have had melanoma. This may be caused by an inherited faulty gene|, but this area is still being researched. People with a very strong family history of melanoma can be referred by their GP to a family cancer clinic (which may be doing research).

Reduced immunity People with a weakened immune system because they have HIV, or people taking drugs that suppress the immune system (after an organ transplant) have an increased risk of melanoma.