SUNBURN - Full extract 

As kids, most of us tore about the beach and soaked up as much sun as we could, only to find out years later how much damage we had done to our skin. It is now clear that the bronze-tanned Aussie is not such a clever image after all. Maybe our Victorian forebears were smarter than we thought. In retrospect their modest bathing costumes, hats, and parasols look rather enlightened.

We can attribute the harmful effects of the sun to invisible ultraviolet (UV) radiation, the shortest wavelength light that reaches the surface of the earth. There are other types of radiation, including electric waves, radio waves, infra-red rays and the spectrum of visible light (red, orange, yellow, green, blue, indigo and violet). Visible light illuminates our days and represents about 50 per cent of the sun's radiant energy. About 40 per cent is in the infra-red portion and 10 per cent is the ultra-violet. Radiation shorter than ultraviolet is absorbed by the earth's ozone layer.

Ultraviolet radiation can be further classified into UVA (wavelength 320-400 nm), UVB (290-320 nm) and UVC (less than 290 nm). UVC is absorbed by the ozone layer. It seems that UVB light does most of the damage-from sunburn right through to degenerative skin changes, skin cancer and eye cataracts. More recently it has been shown that UVA in the 320-360 nm range can also cause problems.

Sunburn is really just an acute heat injury to the skin. It causes all the redness and heat of any intense inflammatory reaction and is often followed by blistering and peeling. Some people become very sick with severe sunburn, mainly because of fluid loss; this is more likely to occur in young children. Fair-skinned, freckly people are far more likely to become sunburnt than those with olive complexions. Prevention is the best approach, with the liberal use of 15+ sunscreens. Wide-brimmed hats, suitable clothing and staying out of the sun between 11am and 3pm are also very important.

There are various types of sunscreen. The older type work by absorbing and scattering UV light before it can damage the skin. Newer sunscreens, containing substances like titanium dioxide, actually reflect UV light away from the skin. A 15+ SPF (sun protection factor) sunscreen means that more than 15 times sun exposure time is required to produce the same degree of redness if that person were unprotected. There is probably little extra benefit in using sunscreens higher than 15 +, nor is it useful trying to work out from SPF readings exactly how much longer you can stay out in the sun before reapplying sunscreen. Although sunscreens are very effective, they should be applied 15 to 30 minutes before going into the sun and reapplied every couple of hours or earlier if you have been for a swim.

Some people can be quiet sensitive to sunscreens and can develop an allergic rash. The rash might be generalised or just over the areas that have been exposed to the light. Sometimes these rashes can be quite obscure and difficult to diagnose. Any reaction to a sunscreen should be discussed with your doctor so that an alternative type can be recommended.

When sunburn does occur there are a few measures that may help. Cool compresses to the affected areas may give some relief, as might old-fashioned soothing creams like calamine lotion. Preparations containing local anaesthetics are best avoided. Sometimes a cortisone cream may be recommended by the doctor. It is better to leave unburst skin blisters alone; puncturing them can lead to infection. Special moist dressings may be necessary where there are weeping areas of broken blisters and raw skin. People with severe generalised sunburn need special attention to ensure that fluid balance is maintained. Hospitalisation may be necessary in some cases.

Exposure to the sun over many years causes premature aging of the skin with excessive wrinkling, irregular pigmentation and crusty spots called solar keratoses. Various skin cancers occur in about two out of three Australians. There is no reason why we cannot still enjoy our out-door activities as much as ever. It is just a matter of being sunsmart, and reaching for the shirt, hat, sunscreen and sunglasses.

Health tip:
* Outdoor activities all year round are great for our health. But we need to be sunsmart…and reach for the shirt, hat, sunscreen and sunglasses.

Dr. Andrew Pattison: Common Consultations
North East Valley Division General Practice, Melbourne, Australia.   Disclaimer
  - Last modified: August 18, 2001