Clinical and dermoscopic evaluation of melanocytic nevi changes during diode laser hair removal: A prospective study

Abstract

Background Laser hair removal (LHR) is a common practice with increasing use worldwide. Clinical and dermoscopic changes in melanocytic nevi after LHR have been reported but prospective studies are lacking. Objective To describe dermoscopic changes of melanocytic nevi at different time points after LHR. Methods Prospective study in a cohort of female patients undergoing diode LHR. Dermoscopic follow‐up of at least three nevi on the legs that underwent hair removal. We included three nonexposed nevi on the arms as controls. Two blinded investigators analyzed dermoscopic images, according to variables selected based on the available literature. Results Thirty‐four patients were included with a total of 148 nevi on the legs and 112 nevi on the arms (controls). 47.9% (71/148) of the nevi on the legs had evidence of dermoscopic changes at the sixth hair removal session, compared to 9.8% (11/112) on controls (p < 0.001). The most frequent change was “bleaching” (41.9%, 62/148). Also, we observed “irregular hyperpigmented areas,” and “regression structures” in 5.4% (8/148) and 4.7% (7/148) of the cases at the sixth session, respectively. Neither of these structures were observed in the controls (p < 0.05). Limitations Only females were included; we did not perform histopathological evaluation nor reflectance confocal microscopy of changing nevi. Conclusion Melanocytic nevi frequently change after diode LHR. The changes cannot always distinguish between LHR induced and melanoma, so we advise avoiding nevi during laser therapies with melanin targets.

Changes in melanocytic nevi treated with laser hair removal: A systematic review

“…19 Of note, the high rate of regression in this study may be due to a longer follow up duration of 2 years and lesions noted to have changes such as bleaching or regression changes in other studies may have progressed to complete regression if followed for a longer period of time. 16 Furthermore, in the aforementioned study by Guicciardi et al, 19 follicular pigmentation and fine telangiectasias were each present in 8 (11%) of nevi surveyed, yet these findings were not noted in reports of treatment with LHR using a diode or alexandrite laser suggesting the possibility that these alterations may be unique to treatment with Nd:YAG LHR or IPL.…”

“…10,15 Commonly reported changes in studies include complete or partial regression, decreased size, laser induced asymmetry, bleaching, darkening, and altered pattern on dermoscopy, namely changes to the reticular or dot globule pattern. 16,17 Regression, asymmetry, gray areas, and loss of pigment network were alterations reported in multiple cases. 4,10,11,[13][14][15] Nasimi et al 17 found a significant correlation between changes in color and in size, while asymmetry was correlated to changes in size only.…”

“…Clinical and dermoscopic changes of nevi following LHR appear to be a common adverse effect, though not robustly studied. The rate of changes within nevi treated with LHR is not established, however in studies by Acle et al 16 and Rasheed et al, 20% of nevi evaluated developed clinical changes, while 48% of nevi had dermoscopic changes and 93% had changes to the reticular patter in studies by Acle et al 16 and Nasimi et al, 17 respectively. 18 In the only controlled trial, the odds ratio for dermoscopic change within nevi was 8.4 (95% confidence interval: 4.2-17) when comparing treated nevi on the legs to control nevi on the arms.…”

“…18 In the only controlled trial, the odds ratio for dermoscopic change within nevi was 8.4 (95% confidence interval: 4.2-17) when comparing treated nevi on the legs to control nevi on the arms. 16 Changes may be more common in darker and coarse Three-year follow-up data for patients from the report by Garrido-Ríos et al 14 was published in a subsequent article by Alvarez-Garrido et al 10 hair bearing nevi. 18 Among 11 patient reports, six patients had clinical and nine had dermoscopic variations following LHR, and six of the patients had multiple affected lesions.…”

“…Despite discordance in time of assessments in available reports, changes were frequently noted when evaluated at 1 month and in some cases increased when assessed at later time points including the maximum available follow up of 3 years, suggesting continued subsequent remodeling. 10,16 Given the lack of long-term follow up, there is inadequate published data to make definitive statements about the effects and safety of treating melanocytic nevi with LHR. However, considering there are no reported cases of melanoma or severe atypia within treated nevi despite the widespread use of LHR since the first device was FDA approved in 1995, a time span of nearly three decades, risk of malignant transformation is unlikely.…”