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  • What causes skin cancer?

    Updated November 2018.
    Our body is made up of tiny building blocks called cells. Cells normally grow, divide, die and are replaced in a controlled way. Cancer occurs when the cells of the body are damaged, causing them to grow out of control. Skin cancer can grow when skin cells are damaged. In most cases this damage is caused by overexposure to ultraviolet (UV) radiation from the sun or artificial sources such as solariums.

    What is UV radiation?

    UV radiation is energy emitted from the sun that is responsible for causing skin damage, premature ageing and skin cancer. UV radiation can’t be seen and unlike infrared radiation (heat) we cannot feel it either. Too much UV radiation causes sunburn and tanning, but not all damage is visible. Every time you’re outdoors unprotected when the UV is 3 or above, there is the potential for skin damage to occur, increasing your skin cancer risk. Skin damage caused by UV radiation is permanent, irreversible and it all adds up. 

    UV levels are not determined by air temperature or sunshine, which means high levels of UV radiation can also occur on cool and cloudy days. Therefore, weather should not be used to determine the need for sun protection.

    There are three types of naturally occurring ultraviolet rays—UVA, UVB and UVC.

    • UVA radiation penetrates deep into the skin, affecting the living skin cells that lie under your skin's surface. UVA causes long-term damage like wrinkles, blotchiness, sagging and discoloration, and also contributes to skin cancer.
    • UVB radiation penetrates the top layer of skin and is the cause of skin tanning, sunburn, and skin cancer. 
    • UVC does not reach the earth's surface and is absorbed or scattered in the atmosphere. However, welding and sterilising equipment emits UVC so UV protection is required.

    When is protection from UV radiation recommended?  

    Once the UV Index reaches a moderate level (3 and above), it is high enough to cause damage to unprotected skin. The higher the UV Index, the more UV radiation is present and the less time it takes for skin damage to occur. Skin should be protected in five ways (Slip, Slop, Slap, Seek, Slide) whenever the UV Index is 3 and above. 

    DNA damage

    Regardless of whether you burn or tan or if there is no visible changes to the skin, unprotected exposure to UV radiation, particularly when the UV Index is 3 and above, causes damage to DNA of skin cells. This damage is cumulative and irreversible, meaning that even when the sunburn heals or the tan fades, the risk of skin cancer remains and builds up over your lifetime. 

    All types of sun tanning and sunburn cause permanent and irreversible damage to your skin. 


    Whenever you are out in the sun, UV radiation will pass deep into your skin’s layers. If you are exposed to too much UV radiation in a short period of time, it may burn your skin, and become visibly red depending on your skin type. This can occur within two to six hours of being burnt and it may keep getting redder for the next few days. Remember—a sunburn may fade but the damage to your skin lasts a lifetime.

    It is important to recognise that skin damage occurs long before any visible signs of sunburn appear. Not all skin types get sunburnt easily, however in South Australia, UV radiation levels are highest from August to May with peak levels over the middle of the day. On a fine January day, a person with fair skin can get sunburnt in fewer than 15 minutes. Remember that skin damage occurs long before signs of sunburn appear and even if your skin type does not burn easily, sun protection is still important. Protect your skin in five ways: slip on sun protective clothing, slop on SPF 30 or higher sunscreen, slap on a shady hat, seek shade and slide on sunglasses.


    Any exposure to ultraviolet (UV) radiation damages your skin, whether it is from the sun or through an artificial source, such as a solarium. A tan is skin cells in trauma and even a light tan is a sign that the skin has been exposed to enough UV radiation to be damaged.  When your skin is exposed to UV radiation, a pigment called melanin is released. Melanin is in the skin’s top layers and is what makes your skin change colour and tan. The release of melanin is your body’s way of trying to protect itself from UV radiation.

    • Fake tans 

    Fake tanning lotions, sprays and creams contain a dye that temporarily stains the skin, giving you a tanned appearance. The dye binds to the skin and comes off when the dead skin cells flake off. Using a fake tanning lotion, spray or cream is a safer alternative to exposing your skin to UV radiation to get a tan, however tanning products do not protect your skin. Some fake tanning products may contain a sunscreen, but this only gives sun protection for the first couple of hours after applying it, not for the time the product lasts on your skin.  

    • Solariums 

    A solarium is an artificial tanning machine that uses high levels of UV radiation to induce a tan. Solariums emit UVA and UVB radiation, both known causes of skin cancer. The use of solariums has been clearly linked to the development of skin cancer, including melanoma and is also not recommended to boost vitamin D levels. In 2014, a state wide ban of commercial solariums came into effect for South Australia.

    For more information on fake tans, read the position statement from Cancer Council Australia.

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