Volume 9, Number 6 SAINT MARY’S COLLEGE HEALTH AND WELLNESS SERVICES March 2005
OUCH! SUNBURN...AND WHAT TO DO ABOUT IT
The best treatment is prevention, but even the most careful woman can get
too much sun.
Every year, about one-third of the adults in the United States suffer sunburn at least once. It’s the skin’s reaction to too much ultraviolet radiation, particularly ultraviolet B (UVB). We all need a bit of UV radiation to make vitamin D, but exposure that causes burning is bad for your skin. Thanks to the ozone layer, only about 10% of UVB rays reach the earth, but they arrive at exactly the wavelength that affects the skin’s outermost layer, the epidermis. Compared to longer-wavelength UVA radiation, UVB is about 1,000 times more likely to cause sunburn. It is more responsible for DNA damage that increases the risk of skin cancer. UVA causes about 15% of sunburns, including those from sunlamps, and it can trigger photosensitivity reactions to certain medicines. UVA and UVB contribute to premature skin aging.
Vulnerability to sunburn depends largely on the skin’s melanin content. Melanin is the protective pigment that gives skin its color. The amount we have is a matter of both heredity and sun exposure. When skin is exposed to UV radiation, the epidermis thickens, and melanin-producing cells generate a tan that helps block the UV rays. People with light skin and little melanin burn very quickly and may never tan. Darker-skinned people have greater protection, although they, too, can burn with prolonged exposure. The back, chest, shoulders, head, and neck are more vulnerable to sunburn than arms, and the arms are move vulnerable than the legs. Unlike a burn from intense heat or a flame, sunburn usually takes a while to become apparent. About 3-5 hours following sun exposure, the skin becomes read, painful, and hot to the touch. It’s red because of blood vessels dilation and inflammation, which also causes pain. If the sunburn is severe enough to blister, the skin may redden sooner. Very fair skin may turn red immediately, as will skin overexposed to UVA light from sunlamps. Most sunburns are first-degree burns. The symptoms peak after 12-24 hours, and the skin usually heals within a few days. At that point, the dead skin peels or flakes off. With a more severe, second-degree burn, swelling and blistering may be accompanied by nausea, fever, and chills. The skin may develop a watery surface. Recovery from severe sunburn can take a week or more.
Most of us know how to avoid sunburn: Regularly apply sunscreen (which absorbs UV radiation), limit exposure during peak hours, and cover up with hats and reflective clothing. Often, despite our best efforts, we still get a sunburn. In most cases, it can easily be treated at home, but more severe burns may require medical help.
BASIC FIRST-AID If you develop mild to moderate sunburn, you can do several
things to reduce burn sensations, pain and inflammation.
•
Take cool baths or showers; apply cold compresses for 10-15 minutes several
times a day. Mix baking soda or a colloidal oatmeal product such as Aveeno
into the bath water to soothe the skin.
•
Take an over-the-counter pain medication, such as acetaminophen (Tylenol)
or ibuprofen (Motrin). Aspirin is also fine but shouldn’t be given
to children.
•
Stay well hydrated by drinking plenty of nonalcoholic beverages.
•
Apply skin moisturizer early and often to help reduce dryness and peeling.
Aloe gel contains substances that may reduce inflammation and pain. Do not
use topical anesthetics (they may cause an allergic skin rash), petroleum
jelly, or oils and butters, which can inhibit healing and make symptoms worse.
WHEN SUNBURN IS MORE SEVERE If you suspect you’ve had a heavy dose of UV radiation (for example, if you fell asleep in the sun or under a sunlamp) contact your clinician right away, before inflammation sets in. You can reduce redness and limit your injury to the epidermis if you get immediate treatment with topical or oral indomethacin or ibuprofen. These drugs have little effect on redness after 24-36 hours. Acetaminophen or aspirin can help relieve pain and fever. Antihistamines are not helpful for sunburn, although they may reduce itching and help you sleep. You may need medical attention if severe blistering occurs or if you experience photosensitive reaction (itchy bumps, red patches, or a rash that resembles sunburn but is out of proportion to the amount of sun exposure). Some people become photosensitive as a result of using certain antibiotics, antidepressants, and other drugs. Try to avoid breaking blisters, because it increases the risk of infection, If your eyes hurt or feel gritty, see an ophthalmologist.
PREVENTION: BEYOND THE OBVIOUS Researchers are investigating the prophylactic use of indomethacin, aspirin and ibuprofen as well as vitamin, mineral, and other supplements to prevent sunburn, speed recovery and reduce skin cell injury. But properly applied sunscreen and limiting sun exposure are still the preventive mainstays. To help plan your outdoor activities, you may want to use the UV Index, a daily forecast of the risk of overexposure developed by the National Weather Service and the EPA. To learn more, visit www.epa.gov/sunwise/uvwhat.html.
FACTORS AFFECTING ULTRAVIOLET (UV) RADIATION INTENSITY AND EXPOSURE
FACTOR EFFECT
Latitude The closer to the equator, the greater the intensity of UV radiation.
Altitude For every 1,000-foot increase in elevation, UVB exposure increases
4% - 10%.
Time of Day Most UV radiation reaches the earth between 11 a.m. and 3 p.m.,
when the sun
is most directly overhead
Time of Year UVB exposure is as much as 100 times greater in summer than
in winter.
Surfaces Snow, sand, water, and even grass reflect UV radiation, increasing
exposure.
Ozone Layer Thickness The ozone layer above North America is thickest – i.e.,
most protective – in late winter and thinnest in late summer and early
fall.