What is it?
A reddening, blistering and eventual burning of the skin when exposed to sunshine. Sunshine can also predispose to the formation of certain skin cancers.
What causes it?
Most westerners perceive that they look better if their skin is brown rather than pale. This leads many millions purposefully to expose themselves to sunshine, usually when on holiday in warm, sunny climates.
The sun continually bombards the earth with all kinds of radiation. Direct exposure to the whole spectrum would be fatal but the earth has a protective layer called the ozone layer which encircles the globe at high altitude. This layer lets through only the relatively harmless long-wave radiation (UVA) and a little of the short-wave type (UVB) which is more dangerous. It is UVB that is the main culprit in sunburn, skin ageing and skin cancers caused by sunlight. Clouds further cut out a lot of the less harmful UVA waves but let through as much as 80 per cent of the UVBs that have got this far. This makes hazy and overcast days just as dangerous as sunny days.
Certain drugs can sensitize people to the sun. All the following make people burn more easily: antibiotics such as tetracycline; diuretics; oral contraceptives; some anti-histamines and tranquillizers; and certain heart medications. Even some perfumes and aftershaves can do this.
Exposure to the sun triggers a chemical reaction to produce a pigment called melanin in the skin.
Melanin absorbs UVBs, and the more the skin is exposed to sunshine the more melanin is produced and the better the protection from the harmful effects of UVBs. Dark-skinned ‘white’ people and, of course, brown-skinned people, have more melanin in their skin anyway and so tan with less sunburn. No tan offers total protection from the sun though. Recent research has found that sun can weaken the body’s immune systems. A group of fair-skinned people were exposed to artificial sunlight for half an hour daily over a two-week period. Tests showed a weakening of the immune system, including a slight reduction in white-blood-cell numbers. In some people these changes remained for up to two weeks after the exposure to the sunlight.
Prevention
The secret of sunburn is to prevent it. Here’s how:
• It takes several days to get used to the sun, so start slowly. Expose yourself for only two half-hour periods a day over the first few days. Increase this exposure as the days go by. Take it especially gently if you are a blonde or a redhead.
• Drink plenty of fluids (not alcoholic).
• Remember that sea-water makes you burn faster.
• Use an effective sunscreen lotion. Most suntan lotions don’t protect you from the burning rays of the sun at all-they are simply fluids that help you ‘cook’. A protective sunscreen will contain a B-complex vitamin called para-amino-benzoic acid (PABA). Tests have found this to be by far the most effective protection against ultraviolet light. PABA still lets some of the UVBs through so you still get a tan, but you don’t burn. It is vital to keep topping up the sunscreen preparation throughout the day because it washes off in water. Experiments with rats found that feeding them vitamins E and Ñ built up a substantial resistance to the burning effects of ultraviolet light but this has not yet been confirmed in humans.
• Remember that water, concrete and sand reflect sun that can burn you badly and quickly.
• The sun is at its most dangerous between the hours of 11a.m. and 3 p.m. so avoid these times, at least at first.
• Wear a hat when you go sightseeing. The hours pass quickly and you can get a lot of sun without realizing it.
• Wear good-quality sunglasses. US ophthalmologists are concerned because they are seeing increasing numbers of people with a condition called macular degeneration. Some believe that this is directly related to sun exposure. It used to be seen only in the elderly but now is occurring in people in their thirties and forties. Experts think that, to be safe, you should wear sunglasses if you are in the sun for more than thirty minutes, and that sun-bathers should not expose their eyes to strong sun for more than fifteen minutes. Polaroid lenses keep out the glare but do not necessarily contain UV filters, and some experts maintain that wearing dark glasses that do not filter out U V light can actually be more dangerous than wearing none at all.
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