The most common photoallergen was oxybenzone. Others included ketoprofen, avobenzone, sulisobenzone, and musk ambrette.
"In the Northwest, mainly in Washington and Oregon, people are compounding ketoprofen, which is a nonsteroidal anti-inflammatory agent, into a topical agent ... that can induce a photoallergic contact dermatitis," Dr. DeLeo explained.
Figure 3: Photoirritant contact dermatitis on the finger due to lime skin.
Newer photoallergens include the sunscreen methylene bis-benzotriazolyl tetramethylbutylphenol (bisoctrizole, brand name Tinosorb M) (Dermatitis 2011;22:106-11).
"This [product] is not available in the U.S., but is available in Europe," Dr. DeLeo noted. However, reactions have been seen among patients using Ahava, an Israeli product sold in the United States. The manufacturers "are apparently saying they are not using it as a sunscreen but as a sort of preservative. So you need to watch out for this one," he said.
In fact, the Food and Drug Administration is considering approval of several new sunscreens, and bisoctrizole is among them, so more cases may be seen, according to Dr. DeLeo.
Another emerging photoallergen is the sunscreen octocrylene. "We haven’t seen any positives to this as yet, but it is being reported in Europe as a very important new photoallergic agent. It may be that they are using a lot more of that as a photostabilizer for avobenzone in Europe than we do in our own cosmetics," he said.
Importantly, there is cross-reactivity among oxybenzone, octocrylene, and ketoprofen, said Dr. DeLeo. Therefore, "those of you who live in the Northwest and see this reaction to ketoprofen may want your patients to avoid oxybenzone and octocrylene as well," he added.
Dr. DeLeo disclosed that he is a consultant for Pfizer, Prous Science, L’Oréal, Limited Brands, Goodyear, Estée Lauder, Mary Kay, and La Roche-Posay.