Sunburns are caused by exposure to too much ultraviolet (UV) light. UV radiation is a wavelength of sunlight in a range too short for the human eye to see. UV light is divided into three wavelength bands — ultraviolet A (UVA), ultraviolet B (UVB) and ultraviolet C (UVC). Only UVA and UVB rays reach the earth. Commercial tanning lamps and tanning beds also produce UV light and can cause sunburn.
When you're exposed to UV light, your skin accelerates its production of melanin. Melanin is the dark pigment in the epidermis that gives your skin its normal color. The extra melanin — produced to protect the skin's deeper layers — creates the darker color of a "tan." A suntan is actually your body's way of blocking the UV rays to prevent sunburn and other skin damage. But the protection only goes so far. The amount of melanin a person produces is determined genetically, and many people simply can't produce enough melanin to protect the skin well. Eventually, UV light causes the skin to burn, bringing pain, redness and swelling.
You can get sunburn on hazy or cloudy days. As much as 90 percent of UV rays pass through clouds. UV rays can also reflect off snow, ice, sand, water and other reflective surfaces, burning your skin as severely as direct sunlight.
Apr. 14, 2011
- Sun and your skin. American Academy of Dermatology. http://www.aad.org/public/publications/pamphlets/sun_sun.html. Accessed March 13, 2011.
- Facts about sunscreen. American Academy of Dermatology. http://www.aad.org/media/background/factsheets/fact_sunscreen.htm. Accessed March 13, 2011.
- Wolf K, et al. Photosensitivity, photo-induced disorders and disorders by ionizing radiation. In: Wolff K, et al. Fitzpatrick's Color Atlas and Synopsis of Clinical Dermatology. 6th ed. New York, N.Y.: The McGraw-Hill Companies; 2009. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=45. Accessed March 13, 2011.
- Brice S, et al. Sunburn. http://www.uptodate.com/home/index.html. Accessed March 13, 2011.
- Habif TP. Light-related diseases and disorders of pigmentation. In: Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 5th ed. Edinburgh, U.K.; New York, N.Y.: Mosby Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-7234-3541-9..X0001-6--TOP&isbn=978-0-7234-3541-9&uniqId=230100505-57. Accessed March 13, 2011.
- Skin cancer prevention and early detection. American Cancer Society. http://www.cancer.org/Cancer/CancerCauses/SunandUVExposure/SkinCancerPreventionandEarlyDetection/skin-cancer-prevention-and-early-detection-what-to-look-for. Accessed March 14, 2011.
- Balk SJ. Ultraviolet radiation: A hazard to children and adolescents. Pediatrics. 2011;127:e791.
- Get set for winter illness season. U.S. Food and Drug Administration. http://www.fda.gov/forconsumers/consumerupdates/ucm092805.htm. Accessed March 14, 2011.
- Anderson CF (expert opinion). Mayo Clinic, Rochester, Minn. March 15, 2011.
- Benzocaine topical products: Sprays, gels and liquids — risk of methemoglobinemia. U.S. Food and Drug Administration. http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm250264.htm. Accessed Apr. 8, 2011.