Sunscreen can prevent skin cancer, but doctors say it must be used properly

Make sure to use sunscreen and reapply every two hours to prevent skin cancer.

Skin cancer is the most common form of cancer in the United States, with almost 68,000 people diagnosed in 2012 with melanoma, the most deadly kind, according to the U.S. Centers for Disease Control and Prevention. But cases can be prevented with proper use of sunscreen, as well as wearing protective clothing and hats and seeking shade, said Dr. Kevin Ferentz, lead physician at GBMC Owings Mills and a melanoma survivor. He answers questions about how to use sun protection.

What ingredients should you look for in sunscreen?

There are two different kinds of sunscreens. The most common use "chemical filters" like oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate. These are chemicals that absorb the dangerous UVA and UVB rays and release their energy as heat. Mineral sunscreens — like zinc oxide and titanium dioxide — are physical barriers that block out the rays. Which product you use is just personal preference.

What ingredients should you avoid, either because they are less effective or potentially harmful to the body in some way?

The chemicals that are in sunscreen are approved by the FDA and are safe. While there have been some studies in animals using incredibly high concentrations of these chemicals that have caused some concerns, the bottom line is you are much more likely to die of skin cancer than you are from using sunscreen. More than 10,000 people die of melanoma in the United States every year.

What SPF number should you look for, and how often do you need to reapply? Are sprays less effective?

SPF — or sun protective factor — tells you how much longer it would take for your skin to get red compared to wearing no protection at all. So if your skin gets red in 10 minutes, and you use an SPF 30 sunscreen, it would take 300 minutes to get red.

The problem is we often don't apply enough sunscreen, so most of us get half of the protection that the SPF number offers. SPF below 15 does not offer "broad-spectrum protection" (UVA and UVB), so it's probably wise to use SPF 30 products. There is generally no need to go over SPF 50. The other important thing is to reapply the sunscreen every two hours. There is also no such thing as waterproof sunscreen. If you are going to use sprays instead of lotion, you should apply several coats of the spray and rub it in. The fine droplets of a spray can miss areas. Also you should not spray your face since we don't know what the effects of inhaling sunscreen might be.

Are the rules different in any way for children? Is it more important for them to cover up with hats and sleeves?

Sunscreen is not recommended for infants under 6 months of age. It's most important to keep babies completely out of the sun. They should be kept in the shade and make sure they wear a hat and keep as much of their skin covered as possible. Use strollers with a canopy. Sunburns in children can lead to skin cancer when they grow up.

What do you do if you get burned?

Most sunburns are first-degree burns which don't blister. The first thing to do for such a sunburn is too cool it down. Use cold compresses made of ice water or take a cool shower or bath. You want to keep the skin moist so put on a moisturizing lotion while the skin is still damp. It's best not to use products like Vaseline. Reapply the lotion to keep the skin moist, especially if it starts to peel. Using anti-inflammatory medication — like ibuprofen or naproxen — helps the pain and can decrease inflammation. Over-the-counter 1 percent hydrocortisone cream can be used, as well as aloe vera. Drink lots of fluid, since the burn may draw fluid to the skin surface and away from other parts of your body. See your doctor if there are blisters over a large part of your body or if you develop chills or a fever. Avoid popping blisters because that can cause the skin to get infected.

There are almost half a million cases of skin cancer in the United States every year, and most of them are completely preventable. Your risk for melanoma doubles after more than five sunburns. And sun exposure also causes premature wrinkling. So enjoy the summer but protect your skin from the dangerous rays of the sun.

meredith.cohn@baltsun.com

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