The main cause of malignant melanoma is ultraviolet (UV) rays from the sun. These damage the skin. People whose skin burns easily are most at risk of developing melanoma – typically people with fair skin, fair or red hair, and blue eyes.

Melanoma is very rare in childhood. However, children and young adults who are overexposed to the sun and have severe burning or blistering are at risk of developing melanoma in later life. It is less common in Hispanic or black people, but more common in women, particularly between the ages of 40 and 60.

As people take sunshine holidays abroad more often, the number of people developing melanoma and other skin cancers is rising. It is also increasing among people who take part in outdoor sports. Damage to the ozone layer, which protects us from UV rays, is also contributing to the increase.

Research has shown that the use of sunbeds (which give off artificial UV radiation) increases the risk of developing malignant melanoma, even if they are only used occasionally throughout the year to maintain a tan. A tan from a sunbed is less protective than a tan from natural sunlight, so a sunbed tan will not protect your skin from the harmful effects of the sun.

Clothing made of closely-woven material can protect the skin. A high-factor sunscreen (SPF 30 or above) should be used on any exposed areas of skin. Using a fake tan to colour your skin can also mean that you do not need to sunbathe.

People who have a lot of abnormal moles (known as dysplastic naevus syndrome) have a higher risk of developing melanoma than other people.

In a few families there are several people who have melanoma. Therefore, it is possible that occasionally melanoma may be caused by an inherited faulty gene. In most people though, this is not the case and if you have melanoma it does not mean that other family members are likely to develop it.

If a member of your family has melanoma and you are worried that you may be at risk of developing it, you can talk to your GP who can reassure you and refer you to a family cancer clinic if necessary.

Research studies have looked at whether the contraceptive pill or taking hormone replacement therapy (HRT) can play a part in causing melanoma. They have found that taking the pill or HRT does not seem to be a cause.