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radiation burn to the skin produced usually by overexposure to the ultraviolet (UV) radiation from the sun. A similar burn can be produced by overexposure to other sources of UV, such as tanning lamps and welding arcs. Exposure of the skin to lesser amounts of UV will often produce a suntan.
Minor sunburns typically cause nothing more harmful than a slight redness and perhaps tenderness to the affected area, though skin damage that is invisible to the naked eye remains even after the burn has healed. Furthermore, this damage is cumulative, so it is best to avoid getting even a minor sunburn. In more serious cases blistering can occur. Extreme sunburns can be quite debilitating as well as producing a lifelong increase in one's susceptibility to skin cancer, in particular melanoma.
In recent years, the incidence and severity of sunburn has increased worldwide, especially in the southern hemisphere, because of damage to the ozone layer caused by air pollution. Another component of the modern world that increases the danger of UV exposure is the fact that some pharmaceuticals can cause a person to be much more sensitive to UV. Among the drugs that can have this effect are common antibiotics, contraceptives, and tranquillizers.
When one is exposed to any artificial source of UV, special protection should be worn. To protect himself or herself from the natural UV of the sun, one should wear long sleeves and wide-brimmed hats or use an umbrella. It is also recommended to avoid prolonged outdoor activities during peak hours of UV exposure -- approximately from 10 a.m. to 3 p.m., if possible. Commercial preparations are available that block UV. These sunblocks have a sun protection factor (SPF) rating. Dermatologists suggest that one should buy sunscreen that has an SPF of 15 or more and that one follow the directions regarding how often to reapply carefully.
It has been noted recently that many Australians are suffering from Vitamin D deficiencies, caused by lack of exposure to sunlight. This can be attributed to a low-level paranoia about exposure to the sun. Some exposure is necessary for health, but as with all things, in moderation.