Ask a Pediatrician: How high should SPF of kids’ sunscreen be?

Q: How high should the SPF be in the sunscreen I use on my children, and how much do they need when we’re at the pool for a few hours?

A: Warm, sunny days are wonderful. Children and adults benefit from spending time playing and exercising outdoors, but it’s important to do so safely.

Help your family have fun in the sun while avoiding harm from those rays. Sunscreen can help protect the skin from sunburn and skin cancer — but only if used correctly. Keep in mind that sunscreen should be used for sun protection, not as a reason to stay in the sun longer.

What to know:

■ Use a sunscreen that says “broad-spectrum” on the label; that means it will screen out both UVB and UVA rays.

■ The broad-spectrum sunscreen should have a sun protection factor (SPF) of at least 30. More research studies are needed to find out if sunscreen with more than SPF 50 offers any extra protection.

■ If possible, avoid the chemical sunscreen ingredient oxybenzone because of concerns about mild hormonal properties. Remember, though, that it’s important to take steps to prevent sunburn, so using any sunscreen is better than not using sunscreen at all. It’s also best to use a cream or lotion-based sunscreen rather than an aerosol spray.

■ For babies, young children, and for sensitive areas of the body, a mineral, or “physical” sunscreen is a very safe choice. Mineral-based sunscreens contain the active ingredients zinc oxide or titanium dioxide and are recommended as safe and effective by the FDA. There are many great choices available, including those that are fragrance free and hypoallergenic.

How to apply sunscreen:

■ Use enough sunscreen to liberally cover all exposed areas, especially the face, nose, ears, feet and hands. Apply under swimsuit straps as well because straps can shift while swimming. Rub in thoroughly.

■ If using a chemical sunscreen, it’s best to apply it 15 to 30 minutes before going outdoors to give it time to absorb. If using a physical sunscreen containing zinc oxide and/or titanium dioxide, there is no need to wait, as the mineral ingredients begin reflecting the UV rays as soon as applied.

■ Use sunscreen whenever you or your child are spending time outdoors. Remember that you can get sunburned even on cloudy days because up to 80% of the sun’s UV rays can get through clouds. Also, UV rays can bounce off water, sand, snow, concrete and reflective surfaces, so make sure you’re protected even if you’re under an umbrella or tree.

■ Reapply sunscreen every two hours and after swimming, sweating or drying off with a towel. Because most people use too little sunscreen, make sure to apply a generous amount.

Sunscreen for babies:

For babies younger than 6 months: Use a mineral-based sunscreen on small areas of the body, such as the face, if protective clothing and shade are not available.

For babies older than 6 months: Apply to all areas of the body, but be careful around the eyes. If your baby rubs sunscreen into his or her eyes, wipe the eyes and hands clean with a damp cloth. If the sunscreen irritates the skin, try a different brand or a mineral sunscreen with titanium dioxide or zinc oxide. If a rash develops, talk with your child’s doctor.

If your baby is younger than 1 and gets a sunburn, call your pediatrician right away. For older children, call your child’s doctor if there is blistering, pain, or fever.

Dr. Sheilagh M. Maguiness is a pediatric dermatologist and the director of pediatric dermatology at the University of Minnesota, Minneapolis. She also is a member of the Section on Dermatology Executive Committee and the chair of the Section on Dermatology Education Sub-Committee of the American Academy of Pediatrics. For more information, go to www.healthychildren.org, the website for parents from the AAP.