Sunburn: What It Is and How to Treat It

Overexposure to the sun is by far the leading cause of skin burns, with consequences ranging from mild sunburn to premature aging and even skin cancer. Most sunburns are classified as first-degree, meaning they are limited to the epidermis, the top layer of the skin. More severe, second-degree burns extend into the dermis, the inner layer of skin. Although very painful, these burns eventually heal as the skin renews itself. Third-degree sunburns, which damage both layers of skin as well as the underlying nerves and subcutaneous tissue, are rare.

Sun can harm a person's skin all year round whether the sky is clear or overcast weather. Of course, the amount of damage depends upon the intensity of ultraviolet, or UV, radiation. In the northern hemisphere, UV radiation is highest in the summer between 10am and 2pm.

Ultraviolet radiation has two components: the shorter UVB rays, which are responsible for most sunburns, and the longer UVA rays, which are involved more in suntanning. Both types cause skin damage as well as promote skin cancer. Over-exposure to UV rays also encourage actinic keratoses; these are scaly lesions that may be precancerous.

The tanning process is the body's way of protecting the skin from the sun's damage. Pigment-producing cells send an increasing amount of melanin to the skin's surface to block the harmful incoming rays. This means that fair-skinned, blue-eyed people who do not readily tan are the most vulnerable to sunburn. Those with dark skin are also susceptible, but their heavier layer of melanin helps protect them against sunburn.

While an occasional mild sunburn may seem harmless, research indicates that any prolonged exposure to the sun causes irreversible damage and increases the risk of cancer. Especially dangerous are blistering sunburns suffered in childhood; even one or two at an early can more than double the risk of developing melanoma, the deadliest of the skin cancers.

First Aid for Sunburns

Mild sunburn may be relieved with a cool shower or cold-water compresses, or by sitting in a tub of cool water to which a cup of cornstarch has been added. Doctors advise against self-care with ointments or lotions that contain the anesthetic benzocaine. They recommend ice packs wrapped in cloth to alleviate severe pain or itching.