HOW TO USE SUNSCREEN
The American Academy of Dermatology guidelines47 recommend daily, year-round use of a broad-spectrum, water-resistant sunscreen with an SPF of at least 30, regardless of age or skin type. Cloud cover and windows block UV-B but not UV-A. Additionally, 80% of UV light can pass through cloud cover, while 25% is reflected by sand and 80% by snow. Thus, sunscreen should be used daily throughout the year.
Sunscreen should be applied to exposed dry skin 15 to 30 minutes before sun exposure, paying particular attention to common areas of nonmelanoma skin cancer, such as the face, ears, hands, arms, and lips. The standard amount of sunscreen used in SPF testing is 2 mg/cm2, which is difficult to translate into real use; most people apply only 25% to 50% of the recommended amount of sunscreen.48 According to the guidelines, 1 oz of sunscreen—2 tablespoons, or enough to fill a shot glass—is enough to cover sun-exposed parts of the adult body. Sunscreen should be reapplied every 2 hours or after swimming or heavy perspiration; many water-resistant sunscreens lose effectiveness after 40 minutes in the water.
Despite the protective effects of sunscreen, the following are still recommended:
- Seek shade or avoid exposure between 10:00 am and 4:00 pm, ie, when the sun’s rays are strongest
- Take caution around water, sand, and snow, which reflect UV radiation
- Wear protective clothing such as long-sleeved shirts, pants, sunglasses, and wide-brimmed hats
- Do not use tanning beds
- Do not use sunscreens to increase the time of UV exposure.
SPECIAL CONSIDERATIONS: INFANTS
Infants and toddlers are at higher risk of UV damage and skin cancer. Structurally, children’s skin is thinner than that of adults and has lower melanin concentrations. Thus, UV penetrates more deeply into skin that is less able to absorb UV radiation. Animal studies suggest that the skin of children, especially infants, is immunologically immature and less able to respond to UV damage than adult skin. Therefore, extra care must be taken to protect children from UV exposure.49
The American Academy of Pediatrics recommends that infants under 6 months of age should be kept out of direct sunlight whenever possible. A broad-spectrum, water-resistant sunscreen with an SPF of at least 30 should be applied to skin that is not protected by clothing or shade (eg, face, hands, neck).50
NEW FDA GUIDELINES AND OTHER PROPOSED CHANGES
The FDA’s SPF labeling requirements remained unchanged; however, the FDA instituted new regulations regarding UV-A protection. Sunscreens that qualify as broad-spectrum are to be labeled as such, indicating that they protect against radiation in the entire UV spectrum. Products that are “broad-spectrum SPF ≥ 15” can now include the following statement in the “drug facts” part of the label: “If used as directed with other sun protection measures, decreases the risk of skin cancer and early skin aging caused by the sun.”
The FDA now requires sunscreens that are not broad-spectrum or that have an SPF less than 15 to include the following alert: “Spending time in the sun increases your risk of skin cancer and early skin aging.”33 These products can only claim protection from sunburn with the statement: “This product has been shown only to prevent sunburn, not skin cancer or early skin aging.”27,28,32,33
In terms of water resistance, the FDA now bans the terms “sunblock,” “waterproof,” or “sweatproof,” as these claims cannot be substantiated. Instead, the label on the front of the package can only read either “water resistant (40 minutes)” or “water resistant (80 minutes).” Also, sunscreens may no longer claim to provide “instant protection,” nor can they claim to maintain efficacy for more than 2 hours without reapplication.27,28,32,33
Some sunscreen products have been labeled with SPF values exceeding 100. The FDA decided that because there is insufficient evidence of clinical benefit for such SPFs, sunscreen product labels may claim a maximum SPF value of “50+.”28,52
The FDA now also specifies approved formulations for sunscreen products. Oils, lotions, creams, gels, butters, pastes, and ointments are acceptable, and this applies to all products that contain sunscreens, including cosmetics. Wipes, towelettes, powders, body washes, and shampoos are not acceptable as sunscreen products. The FDA now considers the popular spray form as potentially acceptable; a final decision awaits the results of further testing.28,53
Editor’s note: As this paper was being sent to press, the US Food and Drug Administration announced that sunscreen manufacturers would have an additional 6 months to comply with the new labeling rules for sunscreens. The new deadline is December 2012. Smaller companies have until December 2013 to implement the labeling changes.