Making Sense of Sunscreen

By Nina Sherak, HealthAtoZ contributing writer

Fun in the sun for kids can spell trouble later in life. Learning that 80 percent of lifetime damage from sun exposure occurs before age 18 is enough to send most moms running for a tube of high-powered sunscreen. Sunscreen is not recommended for babies under 6 months. Keep your infant covered and with a hat on at all times when in the sunlight.

Sunscreens promise protection from the sun's ultraviolet (UV) rays, which can cause sunburn and skin cancer. But how effective are they?

"Sunscreen has been proven to decrease the incidence of skin cancer," says Nicholas Perricone, M.D., and F.A.C.N., assistant clinical professor of dermatology at Yale University Medical School. "However, most people don't realize that sunscreen doesn't give complete protection and is not a ticket to sit in the sun for long periods."

While sunscreen is essential for all children and adults, it is particularly important for those with freckles and moles. According to the American Academy of Dermatology (AAD), an increased number of moles are a significant risk factor for skin cancer. Also, most moles originate in childhood as a result of sun exposure. With the right precautions, you can greatly reduce your child's, as well as your own odds of developing skin cancer.

Sun facts

Sunlight contains two types of ultraviolet rays that reach the earth and can cause sunburn and skin cancer: Ultraviolet A (UVA) and Ultraviolet B (UVB). Because UVA rays pass effortlessly through the ozone layer, the protective layer of atmosphere surrounding the earth, they make up the majority of our sun exposure. Most UVB rays are absorbed by the ozone layer, but enough of these rays pass through to cause serious damage.

Melanoma, the most dangerous form of skin cancer, is thought to be associated with severe UVB sunburns that occur before the age of 20.

Here are some little known sun facts:

1. Ultraviolet rays can penetrate glass and windows.



2. Eighty percent of the sun's damaging rays get through on a partially cloudy day.



3. Heat and brightness do not indicate how intense the ultraviolet rays are, so sunscreen is important in cold weather, too.



4. Reflective surfaces such as sand, water, concrete, snow and white boat decks amplify the sun's damaging rays.



5. Children usually spend three times longer in the sun than adults.

Selecting the right sunscreen

What matters most in a sunscreen is how well it protects you from UV rays. When sorting through the colorful array of sunscreen choices at the drug store, focus on the SPF (sun protection factor) number on the labels. The SPF rating only applies to UVB rays. The AAD recommends the use of sunscreen with an SPF of 15 of higher.

The SPF number tells you how much longer you can stay in the sun without burning if you apply the sunscreen. For example, if you normally would burn after 20 minutes of unprotected sun exposure, applying a sunscreen with an SPF of 15 gives you 15 times the protection and will protect you for as much as five hours. Because normal perspiration and exposure to the elements wears down a protective layer of sunscreen, it is important to reapply it every two hours or more often if you're active or in the water.

Most sun protection products work by absorbing, reflecting or scattering the sun's rays. Sun-blocks, such as the white zinc-oxide cream that lifeguards put on their noses, block the sunrays. Sunscreens contain chemicals that interact with the skin to protect it by absorbing UV rays.

Also, whether your sunscreen is fruit-scented foam or sparkly blue gel, make sure the label says broad-spectrum or both UVA and UVB protection. UVB rays are more likely to cause sunburn than the UVA rays. Ideally, sunscreens should protect against both UV rays.

The most common ingredient in sunscreen that aids UVB absorption is PABA (para-aminobenzoic acid). PABA often is linked to allergic reactions, so if you have sensitive skin, read your sunscreen label carefully and avoid PABA. Other common active sunscreen ingredients include:

• Cinnamates to absorb UVB rays



• Benzophenones to absorb UVA rays



• Anthranilates to absorb both UVA and UVB rays

Cosmetic products such as makeup and lotions that contain some of the same protective chemicals used by sunscreens are now on the market. However, not all of these products meet the standard of having at least SPF 15 and, as a result, do not offer sufficient protection by themselves.

Savvy sunscreen basics

To protect yourself from the sun, follow these simple do's and don'ts:

• Do use a sunscreen with a SPF of at least 15 and apply it at least 30 minutes before sun exposure so a protective layer can bind to your skin.



• Do re-apply sunscreen every two hours when outdoors.



• Do re-apply water-resistant sunscreen every 40 minutes when in the water or perspiring a lot, and re-apply waterproof sunscreen every 90 minutes.



• Do use sunscreen even on cloudy days.



• Do avoid the sun between 10 a.m. and 4 p.m. when the rays are strongest.



• Do make sure that you use a sunscreen that is best for your type of skin. If your skin is dry, use a cream or lotion sunscreen. For oily or acne-prone skin, use an alcohol or gel-based sunscreen. Avoid using alcohol-based sunscreens if you have sensitive skin.



• Don't forget to apply sunscreen on those often forgotten areas; the backs of your hands, behind your knees, your nose, tops of the feet and the ears. Apply sunscreen in front of a mirror before getting dressed to avoid missing any spots.



• Don't apply sunscreen on children younger than 6 months.

Taking antioxidant vitamins before sun exposure may add additional protection. Also, using an under layer of lotion or cream with antioxidants such as vitamin C and alpha lipoic acid, also known as thioctic acid, may be an added benefit to sunscreen alone.

Don't worry if you are just now beginning a diligent campaign against the evils of sun exposure. The good news is that recent studies show daily use of sunscreen with a SPF of at least 15 can help your skin begin to repair itself from prior sun damage.

Related Articles Skin Cancer Preventing Skin Cancer What's the Skinny on Your Skin?

External Sources The American Cancer Society The American Academy of Dermatology

This article was reviewed and updated June 2007.

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