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Sun worshippers beware: Apart from premature ageing of the skin, repeated sunburn can increase the risk of skin cancer.
Skin damage
Think again, if you equate a sun-kissed tan with a healthy skin glow. Dermatologists are clear that repeated exposure to the sun is harmful.
It increases one’s risk of developing skin cancer later in life, said Dr Derrick Aw. This is because exposure to invisible ultraviolet (UV) radiation from the sun damages the DNA of skin cells, he explained.
Skin cancer
UV radiation reaches the earth as long wavelengths known as UVA and short wavelengths known as UVB.
There is also UVC, which are the highest energy UV rays and are more harmful than UVA and UVB rays. Fortunately, the atmosphere's ozone layer blocks out virtually all UVC rays. Long-term exposure to UVA and UVB rays results in cumulative damage to the skin and increases the risk of its cells turning abnormal. This may lead to skin cancer, said Dr Aw.
In Singapore, skin cancer is the seventh and eighth most common cancer in males and females respectively. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma and melanoma.
Cumulative exposure to the sun increases one’s risk of such types of cancer. These are most frequently found on sun-exposed areas of the body in older people, particularly those aged between 50 and 70, said Dr Aw.
Sunburn
Sunburn also increases the risk of skin cancer. A person’s risk of melanoma – the most serious form of skin cancer – doubles if one has had sunburn five or more times.
Exposure to UV light makes the skin increase its production of melanin or pigment. The pigment reacts with oxygen to give the skin a tanned appearance. Tanning is a natural protective response of the skin to sun exposure, said Dr Aw.
However, such protection can only go so far. The amount of melanin a person produces is determined genetically. Many people cannot produce enough melanin to protect the skin well. Eventually, overexposure to UV rays makes the skin burn, resulting in pain, redness and swelling. The skin may also peel.
A sunburn usually resolves on its own, said Dr Aw. To hasten the reduction of inflammation, non-steroidal anti-inflammatory drugs such as ibuprofen may be taken within a few hours of a sunburn.
Photoageing
In addition to skin cancer, repeated sunburns also hasten the ageing process of the skin. Photoageing, another long-term result of sun exposure, refers to the ageing of the skin caused by UV radiation as a result of repeated exposure to the sun over many years.
Premature ageing of the skin – including wrinkles, fine lines, and dry skin – can occur, making a person look older than he is.
Collagen, found in the dermis layer of the skin, is responsible for its structural integrity. Pigmentation can also occur in the form of freckles or melasma, a brown darkening of the skin. The latter is also common during pregnancy or when a woman is on oral contraceptive pills, said Dr Tan.
Use of sunscreens and avoiding the sun are ways to minimise the effects of photoageing, he added. Freckles respond well to intense pulsed light treatment or pigment laser therapy. However, they can recur on exposure to the sun, he said.
Solar keratosis
Another effect of unprotected sun exposure is solar keratosis. They appear as rough, scaly, raised patches that range from flesh to dark pink or brown colour.
They are usually found on the face, ears, lower arms and hands of fair-skinned people whose skin has been damaged by the sun. They are a warning sign of an increased risk of skin cancer.
Early treatment is recommended and may include freezing the skin patch with liquid nitrogen (cryotherapy) and topical applications.
Ref: V10 |