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What are the causes and risk factors?

What causes skin cancer?

The main cause of all types of skin cancer is overexposure to UV radiation. Over 95% of skin cancers are caused by UV exposure. When unprotected skin is exposed to UV radiation, the structure and behaviour of the cells can change.

UV radiation is produced by the sun, but it can also come from artificial sources, such as the lights used in solariums (sun beds). Solariums are now banned in Australia for commercial use because research shows that people who use solariums have a high risk of developing skin cancer.

Most parts of Australia have high levels of UV radiation all year round. UV radiation cannot be seen or felt and it is not related to temperature. It can cause:

  • sunburn
  • premature skin ageing
  • damage to skin cells, which can lead to skin cancer.

Learn more about how to protect yourself from the sun and prevent skin cancer from occurring

Who is at risk of developing skin cancer?

Anyone can develop skin cancer, but it’s more common in older people. The risk is also higher in people who have:

  • fair or freckled skin, especially if it burns easily and doesn’t tan
  • red or fair hair and light-coloured eyes (blue or green)
  • had short, intense periods of exposure to UV radiation, e.g. on weekends or holidays or when playing sport, especially if it caused sunburn
  • actively tanned or used solariums
  • worked outdoors
  • a weakened immune system, which could be caused by taking certain medicines after an organ transplant (immunosuppressants) or by ongoing blood conditions such as chronic leukaemia
  • lots of moles on their body or moles with an irregular shape and uneven colour (dysplastic naevi)
  • a previous skin cancer or a family history of skin cancer
  • certain skin conditions such as sunspots.

People with olive or very dark skin have more protection against UV radiation because their skin produces more melanin than fair skin does. However, they can still develop skin cancer.

This information is reviewed by

This information was last reviewed in January 2020 by the following expert content reviewers: Prof Diona Damian, Dermatologist, The University of Sydney at Royal Prince Alfred Hospital, and Associate, Melanoma Institute of Australia, NSW; Dr Annie Ho, Radiation Oncologist, Genesis Care, Macquarie University, St Vincent’s and Mater Hospitals, NSW; Rebecca Johnson, Clinical Nurse Consultant, Melanoma Institute of Australia, NSW; Shannon Jones, SunSmart Health Professionals Coordinator, Cancer Council Victoria; Liz King, Skin Cancer Prevention Manager, Cancer Council NSW; Roslyn McCulloch, Consumer; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Paige Preston, Policy Advisor, Cancer Prevention, Health and Wellbeing, Cancer Council Queensland; Dr Michael Wagels, Plastic and Reconstructive Surgeon, Princess Alexandra Hospital, QLD. Thanks also to Sydney Melanoma Diagnostic Centre for providing the dysplastic naevus photograph, and to Prof H Peter Soyer for providing the other photographs. We also thank the health professionals, consumers and editorial teams who have worked on previous editions of this title.