Risks and causes of skin cancer
Most non melanoma skin cancers are caused by exposure to the sun. This may be long term exposure, or short periods of intense sun exposure and burning.
Age
The older you are, the more likely you are to develop non melanoma skin cancer. But skin cancers can develop in younger people too.
Sun exposure
Most skin cancers are caused by exposure to the sun. This may be long term exposure, or short periods of intense sun exposure and burning. The ultraviolet light in sunlight damages the DNA in the skin cells. This damage can happen years before a cancer develops.
A history of sunburn increases your risk of skin cancer. The risk is especially high if you were sunburnt several times during your childhood. People who work outside such as farm workers, gardeners and building site workers are also at an increased risk of non melanoma skin cancer.
Skin cancer is more common in people with white skin. This is because they have less of the protective pigment called melanin. People with black skin are less likely to get skin cancer but can still get it.
People with black skin are at risk of developing a type of melanoma skin cancer called acral lentiginous melanoma. This can occur on the soles of feet, palms of hands and nail beds.
Albinism is an inherited genetic condition where the skin makes no melanin at all. People with albinism have very white skin and pale blonde hair. They're at higher than average risk of skin cancer. This is because their skin has no natural protection against the sun.
Sunbeds produce ultraviolet light which damages the skin. Research has shown that using a sunbed causes melanoma. There is now evidence to say that sunbeds might increase the risk of non melanoma skin cancer.
Previous skin cancer
People who have already had a skin cancer have a greater risk of getting another one compared to someone who hasn't had one. Researchers think this is most likely because of sun exposure. You should cover up in the sun and look out for any signs of another skin cancer.
Although there is an increased risk, this doesn’t mean that you will definitely develop another skin cancer.
Family history of skin cancer
Most non melanoma skin cancers don't run in families. But research has found some families seem to have a higher number than normal.
You have an increased risk of developing a squamous cell skin cancer (SCC) if one of your parents has had a SCC. People who have a family history of melanoma have an increased risk of basal cell skin cancer (BCC).
Skin conditions
People with certain skin conditions can be more likely to develop skin cancer. These include:
Solar keratosis is also called actinic keratosis. It's caused by many years of sun exposure. Small rough, scaly and red patches of skin develop, often on the face, hands or scalp (if you are bald). People at higher risk of developing solar keratosis include those who work outdoors, are fair skinned, have red or blonde hair and who burn easily.
Solar keratosis is a sign that your skin has already been damaged and you should take extra care to cover up in the sun. Over time it can turn into a squamous cell skin cancer, but this does not happen in everyone.
Solar keratosis can be treated with cryosurgery, chemotherapy creams, retinoids or photodynamic therapy.
This is a very rare inherited genetic skin condition. It is usually there at birth, but it can appear during the teen years. Your skin cannot repair damage from the sun if you have this condition. You should avoid all sun exposure and other sources of UV light. People with this condition often get skin cancers on exposed skin.
Psoriasis is not a risk factor in itself. Some treatments for psoriasis, such as psoralen ultraviolet light treatment (PUVA), increase your risk as they use ultraviolet light. The exposure is carefully monitored and it's good for your psoriasis. Your doctor carefully balances the benefits and risks of these treatments.
One of the most common types of eczema is atopic dermatitis. It might be treated with ultraviolet light treatment and a drug called methoxsalen (a type of psoralen), which increases the risk of non melanoma skin cancer. The condition itself might increase the risk of skin cancer, but this needs to be researched further.
Other risks
Gorlin syndrome
Also called naevoid basal cell carcinoma syndrome, it's a very rare inherited genetic condition. It causes many BCCs to develop.
Gorlin syndrome can appear in a family with no past history of the condition because of a random gene mutation. But this is unusual.
Past radiation exposure
You are more at risk of developing a non melanoma skin cancer in an area where you have had radiotherapy treatment. You should keep the area covered and use high factor sun cream.
You also have a slightly increased risk of non melanoma skin cancer if you have been exposed to radiation through your job.
Weakened immune system
Having a weakened immune system may increase your risk of skin cancer in the future if you have:
- had an organ or a bone marrow transplant and are taking drugs to stop rejection
- HIV or AIDS
- an inflammatory disease such as inflammatory bowel disease
National guidelines recommend transplant patients have yearly check ups with a skin specialist to learn and look for skin cancer symptoms.
Human papilloma virus
Human papilloma virus (HPV) is a common virus that has several different strains. It plays an important part in the development of skin cancer.
People with certain conditions associated with HPV may be more likely to develop skin cancer. These include the following:
- cervical cancer
- genital warts (caused by HPV types 6 and 11)
- epidermodysplasia verruciformis
Bowen's disease is a very early form of skin cancer. Rarely, it can develop in the genital area. Research into this condition has shown that infection with HPV can increase the risk of developing Bowen’s disease.
Chemicals
Some occupations and working with particular chemicals can increase your risk of skin cancer.
These include the following:
- coal tar
- soot
- creosote
- petroleum products, such as mineral oil or motor oil
- shale oils
- arsenic
Other possible causes
There are often stories about potential causes of cancer in the media. It isn’t always clear which ideas are supported by evidence. There might be things you have heard of that we haven’t included here. This is because either there is no evidence about them or it is less clear.
