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  • What causes skin cancer?

    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 is energy from the sun that can’t be seen or felt, but can cause skin damage and cancer. UV is different to infrared radiation (heat), so you can’t rely on temperature to know when to protect your skin. 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, you are doing damage to your skin and increasing your skin cancer risk. The damage is permanent, irreversible and it all adds up.

    There are three types of naturally occurring ultraviolet rays-UVA, UVB and UVC. UVA and UVB are of concern because of their potential to cause skin cancer.

    • 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.

    Can I get burnt on cloudy days?

    Yes, you can still get burnt on cloudy days, especially if cloud cover is thin. Cloud scatters the UV radiation in all directions and although you receive less direct UV radiation, you may receive more indirectly. Heavy cloud can decrease the amount of UV radiation, while scattered patchy cloud has little or no effect on UV radiation levels.

    How is UV measured? 

    UV radiation levels are divided into low (1–2), moderate (3–5), high (6–7), very high (8–10) and extreme (11) categories. Once UV reaches a moderate level, it is strong enough to cause damage to the skin. That’s why it is important to protect your skin when the UV radiation level is 3 and above. The higher the UV radiation levels, the less time it takes for skin damage to occur.

    The Bureau of Meteorology predicts UV levels with the weather forecast every day and provides us with local daily sun protection times, for example 9.30 am–3.30 pm. The sun protection times tell us when UV is predicted to be 3 and above, which is when sun protection is required. It is a useful tool for anyone planning outdoor activities.

    UV levels and sun protection times can be accessed by downloading the free SunSmart app or by adding the SunSmart widget to your website.

    DNA damage

    Regardless of whether you burn, tan or 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. Your skin cancer risk increases as skin damage builds up over your lifetime. The amount of sun tanning or sunburns you have received, especially during childhood, increases your risk of developing skin cancer, with melanoma being the most dangerous.


    Whenever you are out in the sun, UV radiation will pass deep into your skin’s layers. If you stay in the sun long enough, UV radiation will burn your skin, which may become visibly red (depending on your skin tone). 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 and it does not need to be hot for you to get sunburnt. 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, you can get burnt in fewer than 15 minutes. Protect your skin in five ways: slip on some sun protective clothing, slop on some SPF 30 or higher sunscreen, slap on a hat, seek shade, and slide on some 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.

    Want to know where this information comes from? Click here.

    This website page was last reviewed and updated March 2019.

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