What Happens to Melanocytic Nevi During Laser Hair Removal?

PHOENIX – During the incidental treatment of melanocytic nevi during laser hair removal, common clinical changes include regression and decreased size, while common histologic changes include mild atypia and thermal damage, according to results from a systematic review of literature on the topic. To date, no severe cases of severe dysplasia or melanoma have been reported.

“That’s reassuring,” study author Ahuva Cices, MD, said in an interview at the annual conference of the American Society for Laser Medicine and Surgery, where she presented the results during an abstract session. “But, with that in mind, we want to avoid treating nevi with laser hair removal to avoid changes that could be concerning. We also recommend baseline skin exams so we know what we’re looking at before we start treating with lasers, and any changes can be recognized from that baseline status. It’s important to keep an eye out for changes and always be evaluating.”

In December of 2022, Dr. Cices, chief dermatology resident at Mount Sinai Health System, New York, searched PubMed for articles that evaluated changes in melanocytic nevi after laser hair removal procedures. She used the search terms “nevi laser hair removal,” “nevi diode,” “nevi long pulse alexandrite,” “nevi long pulse neodymium doped yttrium aluminum garnet,” and “melanoma laser hair removal,” and limited the analysis to English language patient-based reports that discussed incidental treatment of melanocytic nevi while undergoing hair removal with a laser.

Reports excluded from the analysis were those that focused on changes following hair removal with nonlaser devices such as intense pulsed light (IPL), those evaluating nonmelanocytic nevi such as Becker’s nevus or nevus of Ota, and those evaluating the intentional ablation or removal of melanocytic lesions.

The search yielded 10 relevant studies for systematic review: seven case reports or series and three observational trials, two of which were prospective and one retrospective.

The results of the review, according to Dr. Cices, revealed that clinical and dermoscopic changes were noted to present as early as 15 days after treatment and persist to the maximum follow up time, at 3 years. Commonly reported changes included regression, decreased size, laser-induced asymmetry, bleaching, darkening, and altered pattern on dermoscopy. Histologic changes included mild atypia, thermal damage, scar formation, and regression.

“Although some of the clinical and dermoscopic alterations may be concerning for malignancy, to our knowledge, there are no documented cases of malignant transformation of nevi following treatment with laser hair removal,” she wrote in the abstract.

Dr. Cices acknowledged certain limitations of the systematic review, including the low number of relevant reports and their generally small sample size, many of which were limited to single cases.

Omar A. Ibrahimi, MD, PhD, medical director of the Connecticut Skin Institute, Stamford, who was asked to comment on the review, characterized the findings as important because laser hair removal is such a commonly performed procedure.

While the study is limited by the small number of studies on the subject matter, “it brings up an important discussion,” Dr. Ibrahimi said in an interview. “Generally speaking, we know that most hair removal lasers do indeed target melanin pigment and can be absorbed by melanocytes. While the wavelengths used for LHR [laser hair removal] will not result in DNA damage or cause mutations that can lead to melanoma, they can sometimes alter the appearance of pigmented lesions and that may change the dermatologist’s ability to monitor them for atypia,” he noted.

“For that reason, I would recommend all patients see a dermatologist for evaluation of their nevi prior to any treatments and they consider very carefully where they get their laser treatments. If they have any atypical pigmented lesions, then that information should be disclosed with the person performing the laser hair removal procedure particularly if there are lesions that are being specifically monitored.”

Dr. Cices reported having no disclosures. Dr. Ibrahimi disclosed that he is a member of the advisory board for Accure Acne, AbbVie, Cutera, Lutronic, Blueberry Therapeutics, Cytrellis, and Quthero. He also holds stock in many device and pharmaceutical companies.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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