A bronzed complexion should not always be the object of envy.

Dr Colin Theng, a consultant dermatologist at the National Skin Centre, said a tan is never healthy and is in fact a response to DNA damage in the skin.

Sun-worshippers should therefore take heed and take along their sunblock whenever they head for the beach or a poolside.

Ultraviolet (UV) light from the sun comes in several wavelengths: UVA, UVB and UVC, the last having the greatest energy level and causing the most damage.

However, UVC seldom makes the news because, fortunately, it is completely absorbed by the atmosphere before it reaches the ground.

UVB is believed to cause damage to the outer layer of the skin, causing sunburn, while UVA rays primarily damage deeper layers of the skin, causing premature ageing.

Therefore, ultraviolet radiation from the sun might cause immediate effects such as skin redness, itch and sunburn, while long-term sun exposure might lead to increased risk of skin cancer, premature skin ageing and wrinkling, and skin pigmentation.

People who are darker-skinned also tan faster, since they have more pigment cells to begin with.

Lighter-skinned people, on the other hand, who have fewer pigment cells, are less protected against the harmful effects of solar radiation. Thus, they might get sunburned relatively easily and thus are more susceptible to sunburn, skin ageing and skin cancers.

Alternatives such as tanning beds and self-tanning sprays and creams, although popular, should be used with care.

Dr Derrick Aw, a consultant dermatologist with the department of medicine at the National University Hospital, said tanning beds, although effective, emit ultraviolet radiation and are just as harmful as tanning in the sun.

Thus, regardless of the use of tanning beds or natural sunlight, cumulative and repeated exposures will result in an increase of skin ageing and cancer risks.

Self-tanning lotions, however, are safer since they do not actually induce a pigmentary response.

Instead, they merely stain the skin and give it an artificial tan.

Dr Aw, however, advised care when using such lotions as a person might have an allergic reaction to a component of the lotion such as a preservative or plant-based additive, which might lead to an itch and redness.

The assumption that the use of sun-tanning lotions that come with a sun protection factor (SPF) is safe is also a mistaken one.

'The protection afforded to the skin is minimal because if there is sufficient protection, a person will not develop a tan in the first place,' said Dr Aw.

Skin cancer is currently among the top 10 cancers in Singapore and there has been an overall increase in its incidence rate.

An average of 325 people here are diagnosed with skin cancer every year, which is triple the average in the 1970s.

However, it is difficult to attribute this trend to the growing popularity of tanning alone as increased sun exposure from work and recreation also increases the risks of skin cancer.

This article was first published in Mind Your Body, The Straits Times on Aug 6, 2008.