A sunburn is reddening of the skin that occurs after you are exposed to the sun or other ultraviolet light.

See also: Sunburn first aid

Sunburn results when the amount of exposure to the sun or other ultraviolet light source exceeds the ability of the body's protective pigment, melanin, to protect the skin. Sunburn in a very light-skinned person may occur in less than 15 minutes of midday sun exposure, while a dark-skinned person may tolerate the same exposure for hours.

It is now recognized that sunburn and sun exposure should not be treated as insignificant. Deaths have resulted from acute sun exposure, and significant temporary disability is experienced by millions of sunburned people each year.

Unlike a thermal burn, sunburn is not immediately apparent. By the time the skin starts to become painful and red, the damage has been done. The pain is worst between 6 and 48 hours after sun exposure. In severe sunburns, blistering of the skin may occur.

Swelling (edema) of the skin, especially in the legs, is common. Toxins are released with sunburn, and fever is not uncommon. Skin peeling usually begins between three and eight days after exposure.

The long-term consequences of years of overexposure to the sun are significant. One blistering sunburn doubles the likelihood of developing malignant melanoma. Chronic sun exposure causes premature wrinkling and aging of the skin. Age spots (lentigo) are a result of sun exposure.

Skin cancer (basal cell and squamous cell cancer) is directly related to the amount of sun exposure (determined by skin pigmentation and hours in the sun). Finally, sun exposure and ultraviolet damage have been implicated in the development of cataracts.

Very effective sunscreens have been developed that protect from UVA and UVB (long and short wavelengths of ultraviolet light), which are the components of sunlight responsible for burning and cancerous changes in the skin.

Sunscreen, protective clothing, and ultraviolet-protected sunglasses are all recommended to prevent excessive sun exposure. Wearing a sunscreen with high sun protection factor (SPF) is recommended. The higher SPF numbers indicate greater protection. Unfortunately, there is no way to get a "safe tan" from the sun.

Sunburn is better prevented than treated. Effective sunscreens are available in a wide variety of strengths. Most doctors recommend a sunscreen SPF level of 30 or greater.

Sunscreen should be generously applied. If out in the sun for a prolonged period of time during the day, wearing a hat and other protective clothing is recommended. Light clothing reflects the sun most effectively.

If you do get a sunburn:

• Try taking a cool shower or bath or placing wet, cold wash rags on the burn.
• Avoid products that contain benzocaine, lidocaine, or petroleum (like Vaseline).
• If blisters are present, dry bandages may help prevent infection.
• If your skin is not blistering, moisturizing cream may be applied to relieve discomfort.
• Over the counter medications, like ibuprofen, may help to relieve pain from sunburn. (Aspirin should be avoided in children who are running a fever.)

Call your doctor if you have a fever with the sunburn or if fluid-filled blisters, dizziness, or vision problems occur with it.

The doctor will perform a physical exam and look at your skin. You may be asked questions about your medical history and current symptoms, including:

• When did the sunburn occur?
• How often do you get sunburn?
• Do you have blisters?
• How much of the body was sunburned?
• What medicines do you take?
• Do you use a sunblock or sunscreen? What type? How strong?
• What other symptoms do you have?

Auerbach PS. Wilderness Medicine. 4th ed. St. Louis, Mo: Mosby; 2001.

Habif TP. Clinical Dermatology. 4th ed. St. Louis, Mo: Mosby; 2004.