Topical solution may be less caustic option than cryosurgery for seborrheic keratosis

A new study suggests that topical 40% hydrogen peroxide solution (A-101) is less toxic than cryosurgery for removal of seborrheic keratosis. The findings were recently published in the Journal of the American Academy of Dermatology.

Cryosurgery is currently the most commonly employed treatment of seborrheic keratosis but cryosurgery can cause blistering, infection, scarring, and pigmentary changes, especially in darker-skinned individuals.

“Given the common nature of these growths and the frequency with which patients seek treatment for them, we wanted to clearly demonstrate at the cellular level the degree of injury, and most importantly, pigmentary changes, from both the gold standard cryosurgery and a newly approved approach, A-101 topical solution,” said Adam Friedman, MD, associate professor of dermatology at the GW School of Medicine and Health Sciences and senior author of the study. “A-101 was found to be less cytotoxic…and less damaging to melanocytes than cryosurgery.”

To better understand the biologic consequences of cryosurgery on melanocytes and the potential for new approaches that can potentially overcome the limitations of cryosurgery, a team of researchers at the George Washington University (GW) School of Medicine and Health Sciences, Washington DC, compared the toxicologic impact of cryosurgery for 5- and 10-second freeze cycles with A-101 at 1 and 2 µL for the treatment of seborrheic keratosis in human skin equivalents derived from darker skin types.

The investigators evaluated skin architecture, metabolic activity, and cytotoxicity, with emphasis on melanocytes, using MTT assay, TUNEL staining, and immunohistochemical staining. “Histologic evaluation of untreated and A-101 vehicle treated tissues revealed a normal stratum corneum, spinous and basal cell layers overlying a well-organized dermis with scattered fibroblasts,” the investigators wrote. In contrast, human skin equivalents treated with cryosurgery for either 5 or 10 seconds demonstrated overall thinning of the epidermis, with more pyknotic cells noted in the deeper spinous layer of the 10 second specimens.

“In both A-101-treated groups, acanthosis of the epidermis and mild pallor was noted, though not to the extent of the cryosurgery-treated specimens, without epidermal clefting,” they added.

More TUNEL-positive cells were identified with cryosurgery compared with A-101, and metabolic activity was reduced, indicating reduced viability, in cryosurgery-treated skin samples. As well, untreated and vehicle-treated skin samples had more melanocytes than cryotherapy-treated samples.

REFERENCE

Stephanie Kao, BA; Alexi Kiss, MD; Tatiana Efimova, PhD; Adam Friedman, MD. “An Ex-vivo Evaluation of Cytotoxicity and Melanocyte Viability after A-101 Hydrogen Peroxide Topical Solution 40% or Cryosurgery Treatment in Seborrheic Keratosis Lesions.” Journal of the American Academy of Dermatology. Published: April 2018.  DOI: 10.1016/j.jaad.2018.03.034.