PracticalDermatology

Given that our largest representative body, the American Academy of Dermatology, recommends the use of SPF to minimize UV exposure and prevent skin cancer and that several other professional and advocacy associations similarly champion sunscreen use, we may take for granted that our peers are using SPF regularly and advising their patients to do the same.

However, amidst campaigns to foster improved UV safety, competing voices encourage patients to seek sun exposure for vitamin D, promote the “beauty” of indoor tanning, and challenge the very safety of sunscreen formulations themselves. Some members of the public are responding to these pro-UV messages. Are dermatologists?

Results of a recent survey of dermatologists suggest that the majority of skin health professionals continue to believe in the importance of sunscreen use.¹ In fact, 97 percent of surveyed dermatologists believe sunscreen use helps lower the risk of developing skin cancer, and 100 percent agree that sunscreen use reduces photoaging. Yet, only three quarters of dermatologists say they typically use sunscreens more than half the time.

In light of the recent survey, this article takes a look at dermatologists’ reported perceptions, as well as some of the facts and so-called controversies of sunscreen use and UV avoidance.

SPF by the Numbers

According to the survey, dermatologists tend to recommend high-SPF sunscreens. About 80 percent of dermatologists believe that higher SPF sunscreens provide an additional margin of safety, and 97 percent say they are comfortable recommending sunscreens SPF 50 or higher.

In the not too distant past, dermatologists were recommending daily application of SPF 15, which then bumped up to 30.

Because the relationship between UVB screening and SPF value is not linear, there has been some confusion, even among clinicians, about the benefits of increasingly higher SPF values. Nonetheless, the consensus among many dermatologists seems to be that the higher the SPF, the greater the long-term benefit to the user. This preference for high SPF could relate to the realization that patients will likely not apply the proper the amount of sunscreen or will not re-apply sunscreen often enough. Assuming that mis-use results in a sunscreen performing below its stated SPF, some dermatologists may believe that recommending a very-high SPF product will result in the patient achieving mid-range SPF performance with real-world use.

Interestingly, SPF 50 is the current cap on SPF in many countries that place an upper limit on SPF claims. The FDA had suggested potentially capping SPF in the use, indicating that a designation such as 30+ or 50+ may be available for products that exceeded the cap.

Under current rules, FDA has not capped SPF values. Nor has the agency provided any system for quantifying the level of UVA screening a product might provide. In today’s marketplace, therefore, it remains important to advise patients not only on the benefits of high SPF, but also on the nature of SPF as a measure of protection against UVB and burning. Patients must be encouraged to select broad-spectrum products that also offer protection against UVA, in addition to UVB.

Formulation Factors

Clearly, all sunscreens are not created equal. Consumer Reports tests sunscreens on a regular basis, and their most recent analysis found that almost half of all evaluated sunscreens performed below their stated SPF.² However, the publication found some top-performing formulations, judging the products based on SPF testing, as well as scent, look, and feel of the formulation. Results from the survey of dermatologists show that they also assess factors such as cosmetic elegance (71 percent) or photostability (42 percent) when recommending sunscreens to their patients.

The issue of photostability has vexed sunscreen formulators for years. Octinoxate, one of the most widely used UVB filters in the US, has been reported to degrade when exposed to sunlight for a short period of time, which leads to a decrease in UV absorption efficacy. There are many ways to improve the stability of this chemical, usually by the use of mixtures of UVB filters. Further, butyl methoxydibenzomethane (avobenzone), a strong UVA 1 filter, is also photo-labile and enhances breakdown of octinoxate. Therefore salicylates or micronized zinc and /or titanium are added to sunscreen mixtures.

Sunscreen products are also formulated with preservative ingredients that help to stabilize the filters. But the safety of these preservatives has been called into question by groups like the Environmental Working Group (EWG).

It should be noted that some longer-lasting UVB filters have come to the US market relatively recently, enhancing the duration of effect of SPF application.

In light of these various facts, dermatologists should continue to emphasize the need to reapply SPF according to package directions, usually every two hours. Patients concerned about specific ingredients can be counseled that there are no conclusive studies or reports—following years of sunscreen use worldwide—that sunscreen ingredients pose a significant threat to human health. Surveyed dermatologists unanimously agree that sunscreens currently marketed in the US are safe.

EWG has challenged the safety of vitamin A derivatives in sunscreens and skincare products. Yet, the recent survey shows that 86 percent of dermatologists believe retinyl palmitate in sunscreens is safe, and more than three-quarters of dermatologists would recommend a formulation containing retinyl palmitate. Similarly, 90 percent of dermatologists say they believe oxybenzone in sunscreens is safe.

Physical sunscreens, such as zinc and titanium dioxide, are not associated with concerns about photostability, therefore, mineral-based sunscreens may provide a longer duration of protection than their chemical counterparts. Some consumer groups have raised alarms about micronized or nano-particle minerals penetrating the skin and creating health risks. These concerns appear to be unfounded. In the current survey, 100 percent of dermatologists say they would recommend sunscreens containing zinc oxide or titanium dioxide to patients.

One point the survey did not appear to address but that warrants discussion with patients is the fact that photostability is just one factor influencing the durability of SPF protection. Sunscreen ingredients—chemical or physical—can be removed from the skin by sweating, swimming, and toweling off. This is another reason patients should follow specific label recommendations on re-application.

Enough is Enough

Of the surveyed dermatologists, 99.4 percent agree that patients typically do not apply enough sunscreen. Proper application technique remains an important but perhaps overlooked aspect of patient education. It takes about 1oz. of sunscreen to cover the body, plus more for the face. That’s a shot-glass full of sunscreen just to cover the body. Where some patients find that a 6oz. bottle of sunscreen lasts them half the summer, it should, in reality last them about five days! And that’s assuming they aren’t outside long enough to require re-application.

Preach. And Practice What You Preach

There’s no ideal sunscreen, and SPF is just one component of UV safety. With this in mind, dermatologists must focus attention on educating patients about which sunscreens to use, as well as when and how to apply them. Every patient can benefit from reminders to practice UV safety and use SPF.

Of course, we could apparently use some reminding, too. As noted above, almost one quarter of surveyed dermatologists do not use sunscreen at least half the time. Close to 20 percent of dermatologists acknowledged that they do not use sunscreen every day. There is always room for improvement, both in our messaging to patients and in our own behavior.

Jonathan Wolfe, MD is an Associate Professor of Dermatology at the University of Pennsylvania.

1. Farberg AS, Glazer AM, Rigel AC, White R, Rigel DS. Dermatologists’ Perceptions, Recommendations, and Use of Sunscreen. JAMA Dermatol. 2017;153(1):99-101.

2. http://practicaldermatology.com/dermwire/2016/05/18/consumer-reports-many-sunscreens-dont-provide-as-much-protection-as-they-claim