Tunel staining revealed 16.4 (plus or minus 0.6424) apoptotic cells per high-powered field in the 5-second cryosurgery experiment and 20.6 (plus or minus 0.6424) in the 10-second procedure. For the hydrogen peroxide treatment, those numbers were 8.65 (plus or minus 0.4122) in the 1 mcL experiment and 12.4 (plus or minus 0.3728) in the 2 mcL experiment.
As expected, melanocytes fared better with the hydrogen peroxide treatment. In the untreated samples, there were 2.5 melanocytes (plus or minus 0.1987) in the untreated sample and 2.0 (plus or minus 0.5000) melanocytes in the vehicle-treated sample. In the 5-second cryosurgery sample, there were 0.45 melanocytes (plus or minus 0.1535), and in the 10 second cryosurgery sample there were 0.2 (plus or minus 0.0918) melanocytes. In contrast, with the 1-mcL hydrogen peroxide-treated sample, there were 1.95 melanocytes in both the 1-mcL and 2-mcL samples (plus or minus 0.1535 for both groups).
“,” Dr. Friedman said. These results, he added, “offer us a lot of insight in terms of how damaging liquid nitrogen is, and it’s good to be reminded of that so that we don’t cause too much harm.”
The authors noted that a clinical trial evaluating the risk of hypopigmentation and hyperpigmentation with 40% hydrogen peroxide in people with darker skin types is underway. In the study, hydrogen peroxide is used to treat dermatosis papulosa nigra.
The study was funded by Aclaris Therapeutics. Senior author Adam Friedman, MD, is a consultant for Aclaris. Dr. Friedman is on the editorial board of Dermatology News.
SOURCE: Kao S et al. J Am Acad Dermatol. 2018 Mar 27. doi: 10.1016/j.jaad.2018.03.034.