Causes and risk factors of skin cancer

Most skin cancers are caused by exposure to the sun. Skin damage can occur due to exposure to the sun over a long period of time or to being exposed to too much sun and getting sunburnt.

People with a history of sunburn or overexposure to the sun in childhood have a greater risk of developing both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Skin damage won’t usually show up until many years later. Sun exposure over a long time is more strongly linked to developing SCC but it can also cause BCC.

People who work outdoors have a greater risk as they are exposed to the sun for long periods of time. Black- or brown-skinned people have a lower risk because the pigment in darker skin gives protection from the sun.

Using sunbeds and sunlamps can increase the risk of developing some skin cancers.

Other risk factors include having had skin cancer before, radiotherapy treatment, Bowen’s disease, having a lowered immune system, overexposure to chemicals and rare genetic conditions.

Sun exposure

Ultraviolet (UV) light from the sun is the main cause of most skin cancers. UV light damages the DNA (genetic material) in our skin cells and can cause skin cancer.

Being exposed to too much sun or getting sunburnt as a child are important risk factors for developing BCCs or SCCs. It is likely that skin damage from UV light during childhood does not show up until many years later.

Skin cancer is more common than it used to be. This is because people are living longer, so their exposure to the sun over their lifetime is greater. Sun exposure over a long time can cause both types of skin cancer. But it is more strongly linked with developing an SCC.

People who work outdoors for a living, such as farm workers, builders and gardeners, are more at risk of developing skin cancer. This is because they are often exposed to the sun for long periods of time.

People with pale-skin who tend to go red or freckle in the sun will be most at risk. Children and young adults who have been over-exposed to the sun have an increased risk of developing some forms of skin cancer, especially if they have pale skin.

Skin cancer will usually show up later in life. It often happens after the age of 40, but it is more common in older age. However, the number of younger people developing skin cancer is also rising.

People with darker or black skin have a very low risk of getting BCCs and SCCs. This is because they have a pigment in their skin called melanin, which gives them protection. But although the risk is much lower, they can still get BCCs and SCCs.

Actinic keratosis

Actinic keratosis (AK), also called solar keratosis, is a crusty skin growth caused by damage from exposure to UV light.

Usually, AK affects mainly the face, scalp and hands. If left untreated for many years, AK may sometimes develop into SCC.


Sunbeds

Using sunbeds and sunlamps increases the risk of developing some skin cancers. The risk increases the more you use a sunbed or sunlamp. It also increases if you were young when you started using them.


Previous skin cancers

If you have had a skin cancer before, you are at risk of getting another one. This could be either in the same place as before (a local recurrence) or somewhere else on your body.

My skin felt very tight and cream helped to soothe it –­ I always had some with me so I could apply it if I was out for the day.

Ronni


Bowen’s disease

Bowen’s disease is sometimes called squamous cell carcinoma in-situ. It is caused by the abnormal growth of cells in the outer layer of the skin (the epidermis). These cells do not spread into the deeper layers of the skin. If left untreated, occasionally Bowen’s disease may develop into SCC. We have more information about Bowen’s disease.


Previous radiotherapy treatment

Having radiotherapy treatment for other conditions can sometimes cause skin cancer (particularly BCC) in the treatment area, later in life.


Lowered immunity

People who have a weakened immune system have a higher risk of developing skin cancer. This can include, for example:

  • people who take drugs that lower their immunity (immunosuppressants) after a transplant of an organ, such as a kidney
  • people who have HIV
  • people with some types of blood cancer, such as chronic lymphocytic leukaemia (CLL).

People with a weakened immune system are more likely to develop SCCs. But BCCs and melanomas are also more common in them than in the general population.

If you need to take drugs to suppress your immune system, the benefit of this outweighs the potential risk of developing skin cancer. However, it is important that you see your doctor regularly to check for early signs of skin cancer.


Exposure to chemicals

Another possible rare cause for non-melanoma skin cancer is overexposure to certain chemicals, usually at work. If you may be at risk from chemicals in the workplace, you should wear protective clothing and use protective equipment. Always follow the manufacturer’s instructions when using chemicals at home.


Genetic conditions

Most skin cancers are not caused by an inherited faulty gene that can be passed on to other family members. However, families are likely to have the same skin type, which may increase their risk of developing a skin cancer.

People with certain rare inherited conditions, such as Gorlin syndrome or xeroderma pigmentosum (XP), have a higher risk of developing skin cancer.


Gender

Men have a slightly higher risk of developing non-melanoma skin cancers than women.

Back to Causes and risk factors

Bowen's disease

Bowen’s disease is a skin condition. Rarely, Bowen’s disease that isn’t treated may develop into skin cancer.