Here comes summer (and sunscreen conversations)!
HERE COMES SUMMER (AND SUNSCREEN CONVERSATIONS)!
By Warren R. Heymann, MD
April 29, 2020
Vol. 2, No. 17
As the summer solstice approaches, days will lengthen, as will patient-related conversations regarding sunscreen use. In this anxiety-ridden age, with all the information overload, patients' questions have expanded beyond what sunscreen we recommend. Concerns for safety — both personal and environmental — are paramount.
As dermatologists, we must be frank about the incontrovertible data that sunscreen use decreases sunburn risk, skin cancer (especially squamous cell carcinoma), and photoaging. When patients obsess about sunscreens, it is incumbent on us to remind them that these agents are only one part of a sun protection strategy including seeking shade, particularly between 10 a.m. and 2 p.m., and wearing appropriate clothing. Focusing on sunscreens without consideration of other avoidance techniques is akin to relying on car airbags without concern for driving sober in a well-maintained automobile.
This year, I anticipate the following questions:
"I heard that sunscreens get into our system. Will that make me ill?"
Matta et al assessed the systemic absorption and pharmacokinetics of 6 active ingredients (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate) in 4 sunscreen products under single and maximal-use conditions. A randomized clinical trial was performed in 48 healthy people. Sunscreen was applied at 2 mg/cm2 to 75% of body surface area at 0 hours on day 1 and 4 times on day 2 through day 4 at 2-hour intervals, and 34 blood samples were collected over 21 days from each participant. The primary outcome was the maximum plasma concentration of avobenzone (and the other filters) over days 1 through 21. Secondary outcomes were the maximum plasma concentrations of oxybenzone, octocrylene, homosalate, octisalate, and octinoxate over days 1 through 21. The authors found that all 6 of the tested active ingredients administered in 4 different sunscreen formulations were systemically absorbed and had plasma concentrations that surpassed the FDA safety threshold for sunscreens. (1) The FDA does not provide any evidence that chemical sunscreens cause harm. Additionally, mineral-based sunscreens are well-established safe alternatives to chemical sunscreens. (2) The fact is that we do not know if this has any health implications whatsoever. Clearly more studies are warranted to determine if there are any carcinogenic, reproductive, or developmental effects. Even Matta et al conclude: "These findings do not indicate that individuals should refrain from the use of sunscreen." (1)
"Will sunscreen use destroy coral reefs?"
Patients are aware that as of January 2021, Hawaii will ban sales of sunscreens containing oxybenzone and octinoxate, both present in the majority of sunscreens, due to concerns of coral reef bleaching. Although in vitro studies of oxybenzone have caused coral reef bleaching, so can warmer water temperatures. Warm water induces corals to expel their algae, causing the coral to turn white (bleached). (3) Even if climate change is the prominent provocateur of coral reef bleaching, dermatologists should be sympathetic with patients concerned about our environment. It is much easier to alter sunscreen use as an individual than to effect climate change in general. For those who are concerned, mineral sunscreens may be utilized instead.
"Will sunscreens cause hair loss?"
Unquestionably, dermatologists have been seeing an increasing number of patients with frontal fibrosing alopecia (FFA), the cause of which is unknown, but likely multifactorial (genetic, hormonal, immunologic, and environmental). Sunscreen use has been considered a culprit, with theories ranging from potential effects on estrogen metabolism to oxidative stress caused by titanium dioxide reacting with ultraviolet light. In their thorough review of this subject, Robinson et al concluded that currently, there is insufficient evidence to establish a direct causal relationship between sunscreen use and FFA. (4). Tosti et al, responding to this article, note that most specialists in hair diseases believe that sunscreens may promote FFA and often discuss sunscreen selection/avoidance with their patients, although American Hair Research Society members do not agree on a potential causative ingredient or type of sunscreen (chemical/physical) to avoid. (5) More studies are warranted; therefore, until such data is forthcoming, perhaps it would be prudent to avoid placing sunscreen at the hairline or on the eyebrows. (4)
"Will sunscreen prevent me from getting enough Vitamin D?"
Neale et al performed a meta-analysis investigating associations between sunscreen use and vitamin D3 or 25 hydroxyvitamin D [25(OH)D] concentration. Eligible studies were experimental [using an artificial ultraviolet radiation (UVR) source], field trials, or observational studies. In the experimental studies sunscreen use considerably abrogated the vitamin D3 or 25(OH)D production induced by exposure to artificially generated UVR. The randomized controlled field trials found no effect of daily sunscreen application, but the sunscreens used only had moderate sun protection factor (SPF) of about 16. The observational studies mostly found no association or that self-reported sunscreen use was associated with higher 25(OH)D concentration. The authors concluded: "There is little evidence that sunscreen decreases 25(OH)D concentration when used in real-life settings, suggesting that concerns about vitamin D should not negate skin cancer prevention advice. However, there have been no trials of the high-SPF sunscreens that are now widely recommended." (6) Given the fact that the use of high SPF sunscreens is now commonplace, it is conceivable that some patients who are strict about sun avoidance and sunscreen use could become deficient in vitamin D. Fortunately, this can be easily measured and rectified by oral vitamin D supplementation (dosed at 800-1000IU daily). (7)
"What sunscreen do you recommend?"
Choosing a sunscreen can be as daunting as choosing a breakfast cereal — anyone can feel overwhelmed by the choices. Sunscreens are either mineral or chemical. Mineral sunscreens contain physical UV filters, such as zinc oxide and titanium dioxide, offering broad-spectrum UV coverage by reflecting or refracting (and even absorbing for titanium dioxide) UV radiation from skin. Chemical sunscreens contain UV filters that absorb UV radiation and, when used in combination, can provide equal if not superior broad-spectrum UV filtration compared with mineral sunscreens. Chemical sunscreens are less likely to leave a residue on the skin, which is more cosmetically acceptable especially on darker skin types. Based on these relative advantages, chemical sunscreens are found in the majority of commonly available sunscreen formulations. (2) My foremost recommendation is for people to choose a sunscreen that they will use — regardless of the SPF on the bottle, it is zero if never applied to the skin (correctly and repeatedly). I usually recommend a broad-spectrum product that is water resistant to 80 minutes. Reasons why people choose one sunscreen over another may be due to a variety of factors — cost, cosmesis, concern for the environment, and potential biological effects. Hence, I will usually recommend mineral sunscreens. You can also point patients to an AAD infographic to help them make appropriate sunscreen choices.
"Is it important to get a sunscreen with a high SPF?"
A broad-spectrum sunscreen with UVA as well as UVB filters and SPF of at least 30 should be applied. (8) Most people (including myself) do not apply sunscreen as recommended, meaning that SPFs are realistically less than advertised. Higher SPFs may compensate for this. Kohli et al conducted a prospective, randomized, double-blind, single-center, split body/face study of 55 healthy subjects comparing chemical sunscreens of SPF 50+ to SPF 100 +. Each subject applied both sunscreens to a randomized side of the face/body for up to 5 consecutive days. The authors found that SPF 100+ was significantly more effective in protecting against UV-induced erythema and sunburn than SPF 50+ in actual use within a beach vacation setting. (9)
"Are oral supplements useful for sun protection?"
Oral niacinamide prevents photoimmunosuppression, thereby inhibiting the development of actinic keratoses and keratinocyte carcinoma. Carotenoids and Polypodium leucotomos, as antioxidants, may diminish ultraviolet B-induced erythema. (7)
"Dr. Heymann, what sunscreen do you choose?"
Usually none — by the time I answer these questions throughout the workday, it's already dark! (That statement was true in the pre-COVID-19 era. Now I find myself taking a mid-day break walking outside my home mid-day.) Truth be told — I'm not fussy — I'm always trying different products sampled in the office, as long as they meet the criteria outlined above. If I actually had to buy a sunscreen, I would purchase a mineral brand.
Point to Remember: Patients will have many legitimate questions about sunscreen use. Dermatologists must acknowledge that we do not have all the answers, and that the ideal sunscreen remains to be developed. Regardless, sunscreen use remains a vital part of a sun protection strategy (seeking shade, photoprotective clothing, hat, and sunglasses) and must be encouraged.
Our Expert's Viewpoint
Henry W. Lim, MD
Chair Emeritus of the Department of Dermatology, Henry Ford Hospital
Senior Vice President for Academic Affairs, Henry Ford Health System
Environmental impact of UV filters and their percutaneous absorption have generated a lot of questions from our patients and the general public. While data are evolving, it is important for us to continue to emphasize to patients that the science of deleterious effects of excessive sunlight exposure is well-established, and that proper photoprotection consists of the entire package of seeking shade when outdoors; wearing photoprotective clothing, a wide-brimmed hat, and sunglasses; and, only on exposed sites, applying broad spectrum sunscreen with SPF>30. For those who are concerned about the potential environmental impact of UV filters, tinted sunscreens with mineral filters can be used.
Dr. Lim had disclosed financial relationships with the following to the AAD at the time of publication: Beiersdorf, Inc., Eli Lilly and Company, Estee Lauder, Ferndale Laboratories, Inc., Galderma Laboratories, LP, Incyte Corporation, ISDIN, Johnson and Johnson, L'Oreal USA Inc., Pierre Fabre Dermatologie, RaMedical, and Unigen. Full disclosure information is available at coi.aad.org.
Editor's note: This commentary was published in an abridged form as "A Clinician's Perspective" in the April 2020 issue of the Journal of the American Academy of Dermatology. The title comes from the song "Here Comes Summer" by Jerry Keller.
All content found on Dermatology World Insights and Inquiries, including: text, images, video, audio, or other formats, were created for informational purposes only. The content represents the opinions of the authors and should not be interpreted as the official AAD position on any topic addressed. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment.
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posted by dermatica at
May 01, 2020
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