Sunburn is an inflammation of the cells of the skin caused by overexposure to the ultraviolet radiation of the sun or a sunlamp. Damage to the skin can be either insignificant or serious, depending on the intensity of the light source, the length of exposure, and the sensitivity of the individual to ultraviolet radiation.

Causes

Sunburn is caused by overexposure to ultraviolet radiation. Substances (such as deodorants, soaps, perfumes, cosmetics, and certain medications) may produce heightened sensitivity to ultraviolet radiation, with a corresponding increase in the severity of the burn. While light-skinned people usually burn more easily than dark-skinned people, skin color is not always a dependable guide to individual susceptibility.

Symptoms

Irritation of the skin and a prickling sensation mark the onset of sunburn; the skin also feels hot to the touch. Capillaries (tiny blood vessels) in the skin become congested because of the release of certain inflammatory agents, thus producing the characteristic redness. Oral contraceptive users may develop irregularly shaped dark splotches, and some sensitive individuals may have allergic reactions in the form of rashes or welts.

As the burn progresses in severity, the skin will feel tight, swollen, and dry or brittle and may become hypersensitive to touch. Overheating and loss of fluids through the damaged skin may also produce dizziness, nausea, vomiting, hyperventilation (rapid breathing, which causes excessive loss of carbon dioxide from the blood), impaired vision and hearing, irregular heartbeat, and loss of consciousness.

The aftermath of severe sunburn often includes blistering and peeling, as well as permanent freckling, splotching, or scarring of the skin. Long-term effects may include premature skin aging, which is marked by chronic dryness, wrinkling, leathery texture, and loss of elasticity. In some cases, melanoma (a form of skin cancer) may be associated with chronic overexposure to sunlight as well as a history of blistering sunburns.

Treatment

Minor sunburn can be effectively treated by a wide variety of nonprescription ointments, oils, powders, creams, and sprays that restore fluids and prevent further drying, relieve discomfort, and promote healing. Many over-the-counter medications contain mild anesthetics to relieve stinging and suppress the desire to scratch itching areas. Infection of blistered and peeling areas of the skin is a common complication. This condition should be treated by a physician.

In the case of severe sunburn, overheating and dehydration (loss of too much fluid) must be avoided. The victim should be taken out of the sun immediately and placed in a cool, shaded area until medical attention can be obtained. Cool (but not cold), wet cloths can be applied to the arms, the head, and the legs. If the victim is perspiring profusely, a fan may help evaporate the water on the skin's surface, thus aiding a natural cooling process.

Prevention

The best prevention of sunburn is simply to avoid prolonged exposure to the direct rays of the sun or a sunlamp. When this is not possible, the first line of defense is to cover exposed areas of the skin completely, preferably with loose-fitting, light-colored clothes made of loose-weave fabrics. Wearing a widebrimmed hat will also help block the sun's harmful rays.

The second line of defense is a sunscreen with an SPF of at least 20 -- available as an oil, cream, paste, or liquid. Most sunscreens are intended to block ultraviolet rays. Many contain para-aminobenzoic acid (PABA). This compound may affect some individuals adversely, particularly those with photosensitivity. For these people, many opaque (light-blocking) creams, pastes, and lotions are available, as well as sunscreens known as benzophenones.