Shining Light on Smart Sunscreen Use

If you’re leaving on vacation and haven’t shopped for sunscreen lately, allow some extra time.

Besides the familiar lotions, you can buy sunscreen as spray, gel or stick. Some sprays and lotions change colors when rubbed in, a feature most often found in products aimed at kids. Lotion may have built-in glitter or insect repellent. Self-tanners sometimes include sunscreen. And the old sun-block standbys, zinc oxide and titanium oxide--the stuff lifeguards sport on their noses--have been improved so they look better.

Knowing the pros and cons of each product can help you minimize the risk of sunburn and, in the long term, skin cancer. But if you’re like most sunscreen users, you may still need a little help to use the product effectively.

Any traveler who will spend time outdoors should pay heed to sun protection, but those headed for the tropics or mountains--where ultraviolet exposure is stronger--should be especially vigilant, says Dr. Richard Wagner, a professor of dermatology at the University of Texas Medical Branch in Galveston and an expert on sun protection.

Those with type 1 skin, which, Wagner says, “never tans, always burns,” should pay particular attention. People with type 1 skin are fair, have some red in their hair and may have lots of freckles, he says. Certain medications--including some antibiotics, antidepressants and antihistamines--also increase sun sensitivity.

Although fair-skinned people are at higher risk of skin cancer, anyone can get it. This year, more than 1 million cases of basal cell and squamous cell cancers, both highly curable, are expected to be diagnosed, according to American Cancer Society projections. Melanoma, the most deadly form, will be diagnosed in about 54,000 people in the U.S. this year.

With all the sunscreen product options, which is best?

The newer sprays and sticks are promoted as less messy and more convenient. But David Steinberg, a Princeton, N.J.-based sunscreen consultant and chemist, thinks lotions are better because they provide a uniform film with no missed spots if applied thoroughly.

Wagner likes the sprays and novelty offerings meant for children because they may inspire more regular use.

And the lifeguards’ zinc oxide and titanium oxide, which scatter or reflect UV rays, are still very effective, Wagner says. The newer formulas use micronized oxide particles that are not noticeable once applied, making them “more cosmetically elegant,” he adds.

Sunscreens should protect against both ultraviolet A (UVA) and ultraviolet B (UVB) exposure, experts concur. Sunburn is associated with the shorter-wavelength UVB. The longer-wavelength UVA, which is associated with aging, damages the skin at deeper levels. But “there’s an overlap,” Wagner says. “B is the shorter, more energetic wavelength. It’s associated with sunburn and skin cancer. But in the laboratory, big enough doses of A also result in skin cancer. And A also causes immunosuppression at the cellular level, which can set you up for skin cancer.”

Be sure the sunscreen has an SPF--sun protection factor--of at least 15, Wagner says. SPF is a measure of how long a product lets you stay in the sun without burning. If you usually begin to burn after 10 minutes, an SPF of 4 multiplies your safe exposure time by four, to 40 minutes; SPF 15 multiplies it by 15, conferring 150 minutes of protection. “Theoretically, you can stop a sunburn if you reapply sunscreen enough,” Wagner says.

If you are at greater than average risk of sunburn or if you are on a medication regimen that increases your sun sensitivity, choose a sunscreen with an SPF higher than 15. Is a product with an SPF of 50 worth it? “You do get a few more percentage points of protection than with an SPF of, say, 30,” Wagner says. “But it’s not double.”

Sunless tanning products--which use dihydroxyacetone, or DHA, to color the skin--don’t always include a sunscreen. But under new federal regulations, the absence of sunscreen must be noted on the label. If you use a sunless tanner, the Skin Cancer Foundation recommends choosing one with an SPF 15 sunscreen.

Tanning pills are not approved by the Food and Drug Administration and do not protect the skin from UV. They have been linked to side effects such as the deposition of tiny crystals in the retina. The crystals are made of canthaxanthin, the coloring agent in the pills that causes the “tan.”

Once you’ve stowed the ideal sunscreen in your luggage, be sure you know how to use it correctly.

How long an application lasts depends on how much you sweat, whether you get wet and other factors. “Waterproof” products are designed to protect for up to 80 minutes in the water, “water-resistant” for up to 40 minutes. “Sweatproof” sunscreens are meant to bond to the skin on contact so the product won’t run off.

Failure to reapply is the downfall of many sunscreen users. Wagner interviewed 67 adult beachgoers who used sunscreen; nearly three-quarters still burned, typically because they did not reapply the product after swimming.

When he questioned the beachgoers who did not go home with a sunburn, he found they reapplied their sunscreen every one to two hours and after swimming. Swimmers who used sunscreen were more likely to burn than nonswimming sunscreen users.

Wagner cites a recent study by the American Academy of Dermatology that found that people who waited more than 2 1/2 hours before reapplying sunscreen had five times the risk of sunburn compared with those who reapplied it every two hours.

If that sounds frequent, Wagner notes that “a British researcher thinks sunscreen should be reapplied every 20 minutes. That obviously hasn’t caught on here.”

It’s also important to use enough. The American Academy of Dermatology recommends using an ounce of sunscreen--enough to fill a shot glass--to cover the exposed areas of the body.

Incomplete coverage is another common mistake, according to the Skin Cancer Foundation. The areas most often overlooked are the ears, temples and neck.