We have been having blazing hot sun in Fayette County, and lots of our patients have questions about sunburn treatment and prevention. We have people that say they “never burn” to those who say they “get fried” in a manner of minutes. We all have different skin tones, which make us susceptible to the harmful rays of the sun. The U.S. Food and Drug Administration and the American Academy of Dermatology recognize six skin-type categories.
Skin Protection Factor (SPF) : how the efficacy of a sunscreen is expressed. It is a ratio of the time required to produce minimal redness with a sunscreen, to the time to produce minimal redness without a sunscreen. An SPF of 15 will allow a person to remain in the sun without burning 15 times longer, than if the skin was unprotected. However, application needs to happen frequently during sun exposure due to sand, swimming or towel drying.
UVA Light: is continuous throughout the day and may exceed the intensity of UVB by up to 1000-fold. Penetrate to the dermis and are responsible for producing tanning but may also damage blood vessels. Causes photoaging (dry, scaling, yellow and deeply wrinkled, thinner & more fragile—it is NOT simply accelerated aging process), photosensitivity drug reactions, and basal cell carcinoma.
UVB light: penetrates the epidermis and is responsible for burning. Most intense between 10am and 4pm. More intense in summer months and higher elevation. A positive effect of UVB exposure is that it produces Vitamin-D in the skin.
UVC: are the most cancer causing but are almost completely absorbed by the ozone layer.