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In March, Connecticut testing laboratory Valisure reported unsafe levels of benzene in a range of anti-acne skin care treatments -- familiar products available from well-known brands. In a petition filed with the FDA, Valisure officials asked the FDA to investigate and recall the affected products, all of which contained benzoyl peroxide, a chemical that can form benzene.

that products containing benzoyl peroxide can form more than 800 times the conditionally-restricted FDA concentration limit (2 parts per million) of benzene, a known carcinogen, in particular levels for leukemia and other blood cancers. A newly published study in provides more details.

Given the ubiquity of the impacted treatments, the findings could mean dermatologists and patients with acne may need to adapt their approaches.

Shari Lipner, MD, PhD, is an associate professor of clinical dermatology with Weill Cornell Medicine in New York and a widely published authority on a range of dermatological topics, including benzene in skin-care products. She recently discussed the recent findings -- and their implications for dermatologists and their patients -- with the Reading Room. The exchange has been edited for length and clarity.

Although the recent report from Valisure garnered significant headlines, this is not a new problem. Did this news come as a surprise to you? Why and how does this issue persist?

Lipner: Benzene is a potential degradation product of benzoyl peroxide, so there are two important unanswered questions for us as dermatologists.

First, can the benzoyl peroxide that we prescribe to patients break down into benzene?

Second, if it does break down, then are there significant benzene concentrations in the product?

How concerned should clinicians and their patients be about the products identified as containing unsafe levels of benzene?

Lipner: Based on the composition of benzoyl peroxide and its breakdown products, it is expected that manipulation of benzoyl peroxide (ie, using heat) would result in release of benzene. Valisure has proven that in the laboratory, benzene is released from benzoyl peroxide.

While physicians should be aware of this data, it is important to note that this laboratory experiment might not recapitulate real-world use of benzoyl peroxide (ie, for most patients, their benzoyl peroxide is not exposed to extreme heat).

How might or should dermatologists adjust their clinical approach in light of this issue? Also, what alternatives are available for patients concerned about benzene exposure?

Lipner: As part of their patient counseling, dermatologists should explain the Valisure data in a manner that patients will understand.

I explain to patients that in the laboratory, when benzoyl peroxide was heated to 50°C (122°F), benzene was later found in the product.

Therefore, benzoyl peroxide should be stored in a cool place and away from sunlight.

I recommend not keeping it in the bathroom where steam from the shower could heat up the product, and not in the car where on an 80°F day, the interior temperature can reach 109°F after 20 minutes.

Patients who are particularly concerned about the safety of benzoyl peroxide could be offered alternatives such as topical clindamycin, retinoids, or azelaic acid.

Is it possible to offer any speculation on any action the FDA might take in response to Valisure's petition to recall products with elevated benzene levels?

Lipner: The FDA will first work to confirm the accuracy of Valisure's data before taking any action.

Is there anything else you think is important to make our audience aware of regarding this topic?

Lipner: As dermatologists, patient safety is our top priority. We must be cautious in counseling patients on benzoyl peroxide use and proper storage, as well as being mindful in discussing alternative treatments.