• Mayo Clinic Q and A: Apply sunscreen generously, frequently for reliable sun protection

little girl on beach in the sun with adult putting sunscreen on her noseDEAR MAYO CLINIC: What are the best kinds of sunscreen to use on kids? Do the spray sunscreens work as well as the lotions? Also, does UPF clothing offer more sun protection than a standard long-sleeved T-shirt?

ANSWER: Children 6 months and older can use the same sunscreen as adults, although sunscreen marketed for children is fine, too. Just make sure that whatever you use is a broad-spectrum sunscreen with a sun protection factor, or SPF, of at least 15. For consistent sun protection that you don’t need to reapply, clothing with universal protective factor, or UPF, is a good choice.

When you look for sunscreen, check that it is labeled as “broad-spectrum.” That means the sunscreen protects against both types of ultraviolet rays: UVA and UVB. UVA is the long wavelength of light that penetrates to the deep layers of skin. UVA leads to skin damage over time. UVB is the shorter wavelength of light that penetrates the surface of the skin and causes sunburn.

SPF is the measure of how well a sunscreen blocks UVB rays. Experts agree that an SPF factor of 15 is the minimum needed to prevent skin damage from UVB. Sunscreens with SPFs higher than 50 provide only a small increase in UVB protection when compared to SPF 30 or SPF 50. That means sunscreens with a very high SPF, such as SPF 100, may not be worth the added expense you pay for them when compared to the protection they offer.

The key to getting the full amount of SPF protection from sunscreen is to apply it generously and frequently. Most people don’t put on enough sunscreen. About two tablespoons of sunscreen, or about enough to fit in a shot glass, should only be enough for your face, your neck and the back of your hands. Reapply sunscreen at least every two hours, or more often if you’ve been sweating or swimming. A sunscreen may be water resistant, but no sunscreen is waterproof.

Sunscreen in a spray is just as effective as sunscreen in a lotion. The sprays can be hard to put on evenly, though. It also can be difficult to get enough sunscreen on in a spray. Lotion is more predictable because you can see and feel where it goes. Because of that, lotion tends to be a better choice for reliable sun protection.

Use sunscreen anytime you’re outside, even if the sun isn’t shining. UV light penetrates through the clouds, and it reflects off water, snow and other surfaces. When reflected, the rays become even stronger, making sunscreen even more important.

If you don’t want to worry about reapplying sunscreen, UPF clothing can be useful, particularly for active children who don’t care to stand still for another round of sunscreen. Many of these clothing items offer an SPF of 50. That’s higher than a standard shirt or hat with a tight weave, which usually has an SPF around 15. UPF clothing also is made to get wet, so a child can comfortably wear it in the water.

For maximum protection from the sun, don’t rely on sunscreen, or even clothing, alone. Try to avoid being out in direct sunlight in the middle of the day when the sun’s rays are strongest. When you’re going somewhere that shade may be scarce, bring an umbrella to use as a shield from the sun. Pack a broad-brimmed hat and sunglasses for you and your children, too. Using these tools, your entire family can stay sun safe. Dawn Davis, M.D., Dermatology, Mayo Clinic, Rochester, Minn.

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