http://www.dermaidfoundation.org Help support DermAid. Donate Now! In this tutorial, Kevin St. Clair M.D., discusses sunscreen and why we need to use it. Please visit our site for more information about other dermatological conditions. Ultraviolet (UV) radiation comprises a portion of the spectrum of energy coming from the sun. Ultraviolet B (UVB) - direct DNA damage; sunburn. Ultraviolet A (UVA) - tanning; aging of the skin. Adequate amount of application, reapplication, and spectrum of UV protection provided by the sunscreen are as or more important than sun protection factor (SPF) number when choosing a sunscreen. Ultraviolet (UV) radiation emanating from the sun causes a number of changes in the skin; some well known and others less well recognized. For instance, most are aware that chronic or excessive sun exposure causes sunburn, tanning, and Skin Cancer. Perhaps less well know consequences of sun exposure are premature aging (e.g. wrinkles, sagging, redness or yellowing, brown spots, thinning and fragility of the skin), decrease in the immune functioning of our skin, interaction with some medications, and worsening or causation of some diseases (e.g. Lupus erythematosus, Porphyria cutanea tarda). While consistent sunscreen use is important, it is not the only measure that should be taken to protect the skin from UV damage. When possible, one should try to perform or schedule outdoor activiites before 11 AM or after 3 PM. Wear appropriate clothing (e.g. longsleeves when possible); use broad-brimmed hats and sunglasses, and seeking shade when available are also important steps. Of course, one should never intentionally "lay out in the sun" or use tanning beds. Traditionally, Sunscreens have been divided into chemical absorbers and physical blockers. Chemical absorbers do just that; these organic compounds absorb UV radiation and convert it to heat. Most chemical absorbers proctect against UVB radiation only (PABA, padimate O, cinnamates, saliacylates, octocrylene, ensulizole). Some absorb both UVB and UVA (benzophenones), where as still others are excellent UVA absorbers (Parsol 1789, Helioplex, and Mexoryl SX). Most commercially available Sunscreens use a combination of these chemical absorbers to maximize protection and water resistance, and minimize problems (such as staining of the skin, degradation upon exposure to sunlight, interaction with each other, and irritation or allergy). Products that contain physical blockers work by reflecting or scattering UV radiation over a broad spectrum. These compounds are inorganic particulates, and by far the most commonly used agents are zinc oxide and titanium dioxide. Iron oxide is occasionally used as well, primarly because it's reddish hue can mask the white opacity of the former two blocker. Until recent years, these products have not been as widely used because of cosmetic unacceptability (i.e. a white hue when applied). However, more recently, microsizing the particles has resulted in much more aesthetically pleasing formulations. These products are broad spectrum, don't degrade easily in sunlight, very rarely cause irritation or allergy, and are often used in children's sunscreens. In December of 2012, the FDA's new requirements for sunscreen labeling will take effect. In order to claim "broad spectrum" protection, a product will have to demonstrate UVA protection and have an SPF of at least 15. Terms such as "waterproof," "sweatproof," and "all-day protection" will no longer be allowed. Sunscreens will be rated either water resistant 40 minutes or water resistant 80 minutes. Products that meet or exceed these criteria may assert that they protect against sunburn, Skin Cancer and premature aging. The FDA is also considering capping the SPF at 50+. Proper application of sunscreen is important. Select a broad spectrum sunscreen with a vehicle appropriate for planned activities (e.g water resistant 80 rating for swimming or expected heavy perspiration). Apply liberally and uniformly approximately 15 to 30 minutes before heading outdoors. While wearing swimming attire, an average adult should apply about 1 ounce of sunscreen (a golf ball sized amount). Reapply every 90 minutes if swimming or perspiring. Adopt other sun protective behaviors, such as seeking shade, broad-brimmed hats, appropriate clothing and sunglasses.

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Skin sense this summer

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