The main cause of most basal cell carcinomas (BCC) is long-term exposure to sunshine (or the UV radiation from sun beds). For this reason, it occurs most often in outdoor workers and in fair-skinned people.

Ultraviolet (UV) light from the sun (or from sun beds) damages DNA, the stuff that holds the genetic code in body cells. Damage to DNA can cause normal cells to mutate and become cancerous.

BCC is more common in men and in people over 50 years old, but the number of cases is increasing in people of all ages.

You may also have an increased risk of BCC because:

you are fair-skinned, have freckles, or have red or blonde hair (because you have less natural protection from sunlight)

you have had BCC previously

you have a family history of Gorlin’s syndrome (basal cell naevus syndrome). In this case your doctor should refer you to a genetics service for advice. Apart from this rare condition, BCCs are not hereditary

you have had an organ transplant – although other types of skin cancer are more likely

you are immunosuppressed

you have worked with tar or mineral oils

you have had a previous course of radiotherapy, for example for ankylosing spondylitis. This is rare, and it usually occurs at least 20 years after the treatment

you have taken something containing arsenic (many years ago some ‘tonics’ contained arsenic, and some older people may have taken one in childhood)

burns, scars or ulcers have damaged your skin. This is rare and it usually occurs at least 20 years after the damage. Most people with these risk factors will not get BCC. If you have worries, discuss them with your GP.
You can not catch basal cell carcinoma from contact with someone who has it.