What's the difference between UVA and UVB?
Ultraviolet A (UVA) rays make the skin tan; ultraviolet B (UVB) rays cause skin to burn. But don't be fooled: A tan isn't healthier. "Both suntans and sunburns are signs that skin cells have been damaged by radiation from the sun," says Kavita Mariwalla, M.D., director of Mohs and Dermatologic Surgery at Continuum Health Partners in New York City. UVB used to get all of the blame for causing skin cancer, but new research shows UVA is equally damaging. This is particularly worrisome since UVA rays are 30 to 50 times more prevalent, and they penetrate deeper into skin cells.
What does SPF stand for? Is a higher number more effective?
An SPF, or sun protection factor, indicates a sunscreen's effectiveness at preventing sunburn. "If your child's skin reddens in 10 minutes without sunscreen, SPF 15 multiplies that time (10 minutes) by 15, meaning she'd be protected from sunburn for approximately 150 minutes or 2 1/2 hours," says Sancy Leachman, M.D., Ph.D., director of the Melanoma and Cutaneous Oncology Program at the University of Utah's Huntsman Cancer Institute in Salt Lake City. Of course, this depends on an adequate application of sunscreen and is based on SPF calculations with artificial instead of natural sunlight. The American Academy of Pediatrics (AAP) recommends using sunscreens with at least an SPF of 15, which blocks 93 percent of UVB rays. Higher SPFs provide even greater protection, but only to a certain point: SPF 30 blocks 97 percent of UVB and SPF 50+ (the maximum SPF you'll find on sunscreen labels due to new Food and Drug Administration (FDA) rules) blocks 98 percent.
What should I look for in a sunscreen? Are sunscreen sticks and sprays as effective as lotions?
As long as you're using a sunscreen with SPF 15 or higher that's broad-spectrum (meaning it blocks both UVA and UVB rays), it doesn't matter whether you use a lotion, cream, gel, stick, or spray. "The problem with some of the easiest and most cosmetically acceptable products is that they often do not adequately block both UVA and UVB. You must look at the ingredients, but the best sunscreen is the one your child agrees to wear," Dr. Leachman says. That said, sprays that contain the "right stuff" are great for on-the-go toddlers and preschoolers. Some young children are sensitive to certain sunscreen ingredients. To test for reactions, apply a small dab on the inside of your child's upper arm and check the area in 24 hours for signs of redness or rash. Sunscreens with titanium dioxide or zinc oxide are often less irritating because the ingredients aren't absorbed into skin. If your child is going to be in the water or getting sweaty, look for water-resistant sunscreens (the FDA has done away with waterproof and sweatproof claims). The new water-resistant labels state how long -- either 40 minutes or 80 minutes -- the sunscreen provides protection before you need to reapply it.
At what age is it safe to put sunscreen on a baby?
Your baby's skin is sensitive and can easily absorb too many chemicals, so avoid sunscreens before the baby is 6 months of age, except those with zinc oxide as the only active ingredient, and use on small areas of her body. Use clothing plus shade as the primary method of protection. Provide additional protection by keeping her out of the sun as much as possible: take walks before 10 a.m. or after 4 p.m., when UVB rays aren't as intense; use a stroller canopy; dress her in lightweight clothing that covers her arms and legs; and choose a wide-brimmed hat or bonnet that covers her face, ears, and neck.
How much sunscreen should I use on my child? How often should I reapply it?
The Skin Cancer Foundation (skincancer.org) recommends that adults use at least an ounce (that's a shot glass) of sunscreen, but there's no set amount for growing children. The important thing is to cover all exposed areas (especially easily overlooked places like ears, tops of feet, backs of knees, and hands) 30 minutes before your child heads outside so her skin has time to absorb it. Reapply at least every two hours, more frequently if she's swimming, playing in water, or sweating.
Do certain products work better on certain body parts?
Sunscreen lotions, gels, creams, and sprays all provide good protection from the neck down. "It's really a matter of which one is easiest to put on your child," Dr. Leachman says. There's less chance of sunscreen sticks getting into a child's eyes, so they're great for foreheads, noses, cheeks, chins, and even ears, but use only sunscreen sticks with components that include zinc oxide and titanium dioxide. A lip balm with an SPF is also recommended. Ultimately, though, Dr. Leachman says "the best sunscreen," is clothing (especially with SPF protection), followed by the lotions, gels, creams, and sticks.