Are you confused by the varying claims of many sun protection products? SSDP Board certified dermatologist Amy S. Chang, MD, helps reduce confusion about sunscreen and its use in this month's issue of the SSDP newsletter.
Q: WHAT IS THE BEST TYPE OF SUNSCREEN?
Dr. Chang: The best type of sunscreen is the one you will use every day. That means finding one that contains broad-spectrum protection and a Sun Protection Factor (SPF) of 30 or higher as well as being non-irritating and cosmetically elegant. "Even the best sunscreen doesn't do you any good sitting in the bottle!"
Q: WHAT IS BROAD-SPECTRUM PROTECTION AND WHY DO I NEED IT?
Dr. Chang: Broad-spectrum protection shields your skin against damage from both UVA and UVB rays. UV radiation is considered the main cause of non-melanoma skin cancers and most experts believe UV radiation frequently plays a role in melanoma, the deadliest form of skin cancer. UVB is the major cause of sunburns while UVA is more prevalent and reaches deeper into the skin to result in premature aging and wrinkling. When you choose a sunscreen, always choose one that provides broad-spectrum protection to keep your skin safe from sunburn, premature aging and skin cancer.
Q: WHAT IS THE MEANING OF SUN PROTECTION FACTOR (SPF)? WHAT LEVEL OF SPF SHOULD I USE?
Dr. Chang: SPF should really stand for "sunburn protection factor." It is a measure of a sunscreen's ability to prevent UVB rays from damaging the skin. The American Academy of Dermatology recommends using a sunscreen with an SPF 30 or higher. SPF 15 blocks about 93 percent of the sun's rays, SPF 30 blocks about 97 percent and SPF 50 blocks about 98 percent of the sun's rays. The important thing to remember is that no sunscreen blocks 100 percent of the sun's rays.
If you never burn, SPF 30 is good for you. But if you have a family or personal history of actinic keratosis (AK) or skin cancer, look for the highest SPF you can find because that little bit of extra protection is important to your skin.
Q: I DO A LOT OF SWIMMING AND OUTDOOR SPORTS. IS THERE A WATERPROOF SUNSCREEN I CAN USE?
Dr. Chang: There is no such thing as "waterproof" or "sweat proof" sunscreen. Instead, sunscreens are labeled either Water Resistant or Very Water Resistant. Water resistant sunscreen is effective for up to 40 minutes in water; very water resistant sunscreen is effective for up to 80 minutes in water. Be sure to reapply your sunscreen after swimming, toweling off or sweating to maintain its effectiveness.
Q: DOES MOISTURIZER WITH SUNSCREEN PROVIDE ADEQUATE SUN PROTECTION?
Dr. Chang: If you're just commuting to and from the office, then a moisturizer with sunscreen is adequate. But if you're going to the beach or for a walk or run, you're going to need a sunscreen that is water resistant or very water resistant. I recommend most people have two products for sun protection: one for everyday activities and the other for the beach, water sports and other outdoor activities.
Q: WHAT MISTAKES DO PEOPLE MAKE REGARDING THE USE OF SUNSCREEN?
Dr. Chang: One is they don't use sunscreen on a daily basis. I recommend using sunscreen every day, not just during the summer. People are often caught off guard either being out longer than expected or forgetting that UV exists all year round and penetrates clouds and glass.
Two, a lot of people don't apply enough sunscreen or they fail to reapply it. You should use enough sunscreen to fill a shot glass (2 ounces) to cover all exposed areas of the body.
Three, many people don't remember to apply sunscreen before going out. For the greatest protection, apply sunscreen 20 minutes before exposure and reapply it every two hours or after swimming or sweating.
Four , spray sunscreen requires close proximity application and several passes for desired effect. In general, patients who use sunscreens but end up with sunburns and deep tans have been using spray sunscreen that was likely applied improperly. I advise my patients to use spray sunscreens only for reapplication and hair-bearing areas.
Q: WHAT IS THE DIFFERENCE BETWEEN A PHYSICAL AND A CHEMICAL SUNSCREEN?
Dr. Chang: A physical sunscreen works by deflecting the sun's rays and may contain the active ingredients titanium dioxide and/or zinc oxide. Physical sunscreens not only protect against both UVA and UVB rays but are less absorbed and less irritating for individuals with sensitive skin. In recent years, physical sunscreens have been formulated to be more cosmetically elegant and less visible when applied to the skin. A chemical sunscreen protects by absorbing the sun's rays and may contain one or more of many active ingredients, such as oxybenzone, PABA, cinnamates, or salicylate. Most chemical sunscreens protects against UVB only. Few such as oxybenzone have both UVA and UVB coverage. Chemical sunscreen are more likely to cause irritation.
Q: IS MY SUNSCREEN FROM LAST SUMMER STILL GOOD TO USE?
Dr. Chang: Sunscreen does have a shelf life. Look at your sunscreen container every year to see if it's past its expiration date. If it is, throw it out.
Sunscreen can be sensitive to heat so if you leave it in a hot car, it may not work as well. If you find you're using sunscreen and still getting tanned or burned, it means your sunscreen isn't working. Check the SPF, UV coverage, and expiration date. If you are applying it properly, it is time to throw it out and get a new one.
To make an appointment with Board certified dermatologist Amy S. Chang, MD, or one of the other physicians at SSDP, phone 508.535.3376 or email us from the contact page of the SSDP website. Visit the SSDP website at www.southshorederm.com to learn more about all of the talented physicians in our group.