NEW YORK — Several factors contribute to patients' poor use of sun block, including vague package instructions, a lack of understanding about proper use, and the perception that a little sunscreen goes a long way, Heidi A. Waldorf, M.D., said at the Atlantic Dermatological Conference.
“The analogy I use for patients is that if you have a car that has a great safety record, has airbags all over, and has been crash tested, you still shouldn't drive 95 miles an hour on a slick road,” Dr. Waldorf of Mount Sinai School of Medicine, New York, explained. “That analogy is to say that just because you have a good sunscreen on, you shouldn't lie out or stay out all day. Sunscreen is just part of protection.”
The proper application of sunscreen is the key to adequate protection, Dr. Waldorf said.
“People generally apply only 25%–50% of the sun block needed to provide the SPF they think they are getting. A product with an SPF of 30 may be affording them an SPF of 15 or 8 if they are applying it incorrectly.” She suggested giving patients seven tips to ensure the proper use of sunscreen. (See box.)
A recent study in the Archives of Dermatology found that despite campaigns promoting early detection of skin cancer and the merits of avoiding prolonged sun exposure, the rate of the most deadly and aggressive form of melanoma has remained the same over 12 years (from 1988 through 1999).
So what's a doctor to do?
Start by telling patients to cover up while in the sun. “Think of the Bedouins—they swathe themselves in clothing,” Dr. Waldorf said.
It's also important to address recent coverage about the need for sun exposure for vitamin D supplementation. “People only need 10–15 minutes of exposure a day on the tops of the hands, face, or upper back to fulfill the daily requirement. Most people will get that much just running an errand or walking to their cars,” she said at the conference, sponsored by the Dermatologic Society of Greater New York.
Seven Reminders About Effective Sunscreen Use
1. Apply sunscreen at least 30 minutes before planned exposure.
2. Wear only a bathing suit or underwear during initial application to avoid skipping spots that may result in sunburn.
3. Reapply sunscreen within the first 30 minutes of exposure.
4. Make sure each application equals a shot glass of product (a minimum of a half teaspoon for each limb and other areas).
5. Reapply a full application of sunscreen every 1–2 hours.
6. Reapply water-resistant sun block after getting wet and toweling off.
7. Know which active ingredients to look for. “The active ingredients should include zinc oxide, titanium dioxide, and avobenzone or Mexoryl. (Mexoryl is not available in U.S.-made products but is in products available over the Internet or abroad.)
Source: Dr. Waldorf