Update on photoprotection: What dermatologists need to know

Recent controversy over sunscreen safety has patients concerned. Yet, dermatologists know that photoprotection, including sunscreen, remains an important step in decreasing the rate of skin cancer.

Former AAD President Henry W. Lim, MD.

Friday’s session, “Photoprotection” (U013) shines a light on these concerns, and explores the current status of UV filters, the active ingredients in sunscreen. Former AAD President Henry W. Lim, MD, leads the discussion over the current status of UV filters, the active ingredients in sunscreen. Dr. Lim is chair emeritus of the department of dermatology and senior vice president for academic affairs at Henry Ford Health System in Detroit.

The environmental impact

The environmental impact of UV filters on marine life, specifically coral reefs, has cast two UV filters into the hot seat — oxybenzone and octinoxate.

“There are data to suggest that, in laboratory settings, oxybenzone and octinoxate can kill coral reefs. However, it has also been shown that the amount of UV filters found in laboratory settings that would kill coral reefs are significantly higher than the amounts found in the ocean.  Multiple studies have also shown that one of the major causes of coral reef bleaching is the rising temperature of ocean water,” Dr. Lim said. “However, because of concerns raised by those sets of [UV filter] data, the state of Hawaii passed a law that, starting in 2021, sunscreen containing oxybenzone and octinoxate will not be allowed to be sold in Hawaii. The city of Key West in Florida has passed similar types of laws.”

Connecting frontal fibrosing alopecia to sunscreen use

“Multiple studies have shown that many frontal fibrosing alopecia patients tend to use sunscreen more commonly than those individuals who don’t have frontal fibrosing alopecia,” said Dr. Lim. “Therefore, there is an association between the use of sunscreen and frontal fibrosing alopecia.”

It remains to be seen, though, what exactly is in sunscreen that may be associated with frontal fibrosing alopecia. Because individuals in surveys use different kinds of sunscreen, and therefore different kinds of UV filters, there is currently no clear indication which filter(s), if any, is responsible.

“It should be emphasized that this association does not prove that there is a cause-and-effect relationship,” Dr. Lim said. “More studies clearly need to be done to resolve this issue.”

Regulatory matters

An FDA-proposed rule, released in February, classifies the UV filters in sunscreens into three categories. Titanium dioxide and zinc oxide are in the first category, which means they are considered to be safe and effective.

“On the other hand,” Dr. Lim said, “for 12 filters, including seven commonly used ones in the U.S., the FDA is requiring more studies on their safety.”

The FDA recently published a study that when sunscreens were applied under maximal use condition (on 75% of the body surface, at 2 mg/cm2, every two hours during the day for four days), there were detectable blood levels of all four filters evaluated.

“Sunscreen has been used since the 1970s by literally millions of people without known systemic side effects,” he said. “Therefore, the clinical significance of these findings needs further study.”

In a recent Dialogues in Dermatology podcast, Dr. Lim said the AAD would be “more than happy” to work with the FDA to develop safe, new UV filters. Unfortunately, he said, it’s been two decades since the U.S. approved a new filter. He noted that Europe and other countries are already approving newer filters that have proven to be safe. Meanwhile, Dr. Lim said the FDA says even current sunscreens haven’t been adequately tested.

Making sense for patients

Although there are controversies on UV filters, the deleterious effects of excessive UV exposure is well established, Dr. Lim said. He urged dermatologists to continue to educating patients to use photoprotection. This includes, as always, encouraging the public to seek shade when outdoors, wear photoprotective clothing, such as a wide-brimmed hats and sunglasses, and apply sunscreen on exposed areas.

To listen to Dr. Lim’s full podcast on this topic, visit https://aad-lms.s3.amazonaws.com/Dialogues/DID0719/2_Sunscreen.mp3.