skin disorders
Sunburn
Prevention of Sunburn
Avoid overexposure to sun Wear protective clothing Use sunscreens The best—and most obvious—way to prevent sun damage is to stay out of strong, direct sunlight. Exposure to bright midday sun should be avoided, even for people with dark skin. UV rays are not as strong before 10 AM and after 4 PM. If sun exposure is unavoidable, the person should seek shade as soon as possible, cover up in UV-protective clothing, and wear sunscreen, a broad-brimmed hat, and UV-protective sunglasses. Many materials are capable of filtering or blocking UV radiation, but many are not. Clothing, ordinary window glass, smoke, and smog filter out many of the damaging rays. However, water is not a good filter. UVA and UVB light can penetrate a foot (about 30 centimeters) of clear water. Clouds and fog are also not good filters of UV light—a person can get sunburned on a cloudy or foggy day. Snow, water, and sand reflect sunlight, magnifying the amount of UV light that reaches the skin. People also burn more quickly at high altitudes, where the thin air allows more burning UV light to reach the skin, and low latitudes (such as at the equator). Although sun exposure helps generatevitamin D, many experts recommend maintaining adequatevitamin Dlevels by consuming supplements if needed rather than by intentional overexposure to sunlight (5 to 15 minutes of sun exposure on the arms a few days a week is probably enough to maintainvitamin Dlevels). The sun's damaging effects can be further minimized by wearing protective coverings such as hats, shirts, pants, and sunglasses. Fabrics with a tight weave block the sun better than fabrics with a loose weave. Special clothing that provides high sun protection is commercially available. This type of clothing is labeled with ultraviolet protection factor (UPF) followed by a number that indicates the level of protection (similar to sunscreen labeling). Broad-brimmed hats help protect the face, ears, and neck, but people still need to apply sunscreen to these areas. People should regularly wear UV-protective, wrap-around sunglasses to help shield the eyes and eyelids. Before exposure to strong direct sunlight, a person should apply a sunscreen, which is a cream or lotion containing chemicals that protect the skin by filtering out UV light. Older sunscreens tended to filter only UVB light, but most newer sunscreens effectively filter UVA light as well. Sunscreens are available in a wide variety of formulations, including creams, lotions, gels, foams, sprays, powders, and sticks. Self-tanning products do not provide significant protection from UV exposure. Chemical sunscreenscontain several substances that absorb UV radiation. Ingredients that absorb UVB radiation include cinnamates, salicylates, and para-aminobenzoic acid (PABA) derivatives. Benzophenones block UVA and UVB light. Avobenzone and ecamsule filter in the UVA range and may be added to provide further UVA protection. Barrier or mineral sunscreenscontain the substanceszinc oxideor titanium dioxide, which reflect both UVB and UVA rays (thus blocking them from reaching the skin). These once thick, white ointments have been reformulated to create a more transparent layer while still blocking almost all sunlight from the skin. These newer sunscreens have a more pleasing thickness and color, which allow them to be combined with other traditional chemical blockers, thereby providing even more sun protection to a given formulation. Some cosmetics also containzinc oxideor titanium dioxide. All chemical sunscreen ingredients are thought to be absorbed by the body to some degree. Although most ingredients cause minimal side effects, some do have potential risks, and others are currently being studied. Traditional barrier sunscreens have relatively large mineral particles that are not absorbed by the body and are currently considered safe. Newer formulations of mineral sunscreens are made with extremely small particles (nanoparticles) that may be absorbed by the body. Although these nanoparticles are thought to be safe, they are still being studied. People concerned about the effects of absorbed nanoparticles may prefer to use so-called "non-nano" mineral sunscreens. In the United States, the Food and Drug Administration (FDA) rates sunscreens by their sun protection factor (SPF) number—the higher the SPF number, the greater the protection. Sunscreens rated between 2 and 14 provide minimal protection, those rated between 15 and 29 provide good protection, and those rated 30 and above provide maximum protection. Products that protect against sunburn and photoaging, and also reduce the risk of skin cancer, are labeled broad spectrum and have an SPF of 15 (or higher). The SPF, however, only quantifies the protection against UVB light exposure. There is no scale for UVA light protection. For the best protection,people should use a broad-spectrum, water-resistant sunscreen with an SPF rating of 30 or higher. One ounce (about 30 milliliters) should be used to cover the entire body surface of an average-sized person. Sunscreens can fail if not enough of the product is applied, if the product is applied too late (sunscreens should optimally be applied 30 minutes before exposure to the sun), and if the product is not reapplied after swimming or sweating (even sunscreens labeled as water-resistant) or every 2 hours during sun exposure. Most people apply less than half the recommended amount of sunscreen. An ounce of sunscreen (about 30 milliliters or enough to fill a standard shot glass) is usually needed to cover the entire body. Most people apply less than half that. Sometimes sunscreens cause allergic reactions. People may react to the sunscreen after applying it or after applying it and then going in the sun (called a Chemical photosensitivity ). Some dermatologists can do tests to diagnose such In a word—no. Although a suntan is often considered an emblem of good health and of an active, athletic life, tanning for its own sake has no health benefit and is actually a health hazard. Any exposure to ultraviolet A or B (UVA or UVB) light can alter or damage the skin. Long-term exposure to natural sunlight causes skin damage and increases the risk of skin cancer. Exposure to the artificial sunlight used in tanning salons is harmful as well. The UVA lights used in these establishments cause the same long-term effects as exposure to UVB light, such as wrinkling and mottled pigmentation (photoaging) and skin cancer. Quite simply, there is no safe tan. Self-tanning, or sunless, lotions do not really tan the skin but, rather, stain it. They therefore provide a safe way to achieve a tanned look without risking dangerous exposure to ultraviolet rays. However, because they do not increase melanin production, self-tanning lotions do not offer protection from the sun. Therefore, sunscreens should still be used during exposure to sunlight. Results with the use of self-tanning lotions may vary, depending on a person’s skin type, the formulation used, and the manner in which the lotion is applied. Polypodium leucotomos(a natural tropical fern extract) and nicotinamide (a form of vitamin B3) are supplements that are taken by mouth that provide some protection against the damaging effects of sunlight. However, they are not a replacement for other methods of sun protection. 