Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2024;14(3):e2024162 1 Dermatoscopic Changes in Melanocytic Nevi After Intense Pulsed Light Treatment for Hair Removal: A Case Series Nicoleta Neagu1, Caterina Dianzani2, Gianluca Avallone3, Iris Zalaudek4, Domenico Piccolo5, Giovanni Pellacani6, Sebastian Laspina7, Claudio Conforti8 1 Department of Epidemiology, University of Medicine, Pharmacy, Science and Technology ‘George Emil Palade’ of Târgu Mureş, Târgu Mureș, Romania 2 Plastic and Reconstructive Surgery Unit, Campus Bio-Medico University of Rome, Rome, Italy 3 Section of Dermatology, Department of Medical Sciences, University of Turin, Turin, Italy 4 Department of Dermatology, Maggiore Hospital, University of Trieste, Trieste, Italy 5 Skin Center-Dermo Aesthetic Laser Centers, Avezzano, Pescara and L’Aquila, Italy 6 Dermatology Unit, Department of Clinical Internal Anesthesiological and Cardiovascular Sciences, “Sapienza” University of Rome, Rome, Italy 7 Private practice, CLDL, Udine, Italy 8 IDI-IRCCS, Dermatological Research Hospital, Rome, Italy Key words: intense pulsed light, nevi, post laser treatment, hair removal, dermoscopy Citation: Neagu N, Dianzani C, Avallone G, et al. Dermatoscopic Changes in Melanocytic Nevi After Intense Pulsed Light (IPL) Treatment for Hair Removal: A Case Series. Dermatol Pract Concept. 2024;14(3):e2024162. DOI: https://doi.org/10.5826/dpc.1403a162 Accepted: February 27, 2024; Published: July 2024 Copyright: ©2024 Neagu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Claudio Conforti, MD, IDI-IRCCS, Dermatological Research Hospital, Via dei Monti di Creta 104, 00167 Rome, Italy. Email: claudioconforti@yahoo.com Introduction Lasers and intense pulsed light (IPL) systems have become increasingly popular in dermatology and aesthetic medicine in the past two decades. Most frequently, they have been em- ployed in unwanted hair removal procedures maintaining long–term results [1]. Their mechanism of action is through selective photothermolysis, by which photons exclusively target the hair follicle [2]. However, when applied in close proximity to a nevus, the energy absorbed by nevomela- nocytes might induce thermal damage [3]. We report the dermatoscopic changes of nevi in five patients who under- went IPL for hair removal. Case Presentation The dermatoscopic changes we have observed in our pa- tients include brown pigmentary blotches with or without crust formation, gray-blue globules, gray-blue homoge- nous areas, loss of pigment network, homogenous brown- gray areas and a peppering morphology (Table 1 and Figure 1). 2 Research Letter | Dermatol Pract Concept. 2024;14(3):e2024162 Table 1 . Case series characteristics Gender, Age (years) Intense pulsed light sessions Time interval between intense pulsed light and nevi photography Atypical nevi Dermatoscopic changes of nevi Case 1 M, 37 1 1 month 8 4 nevi with brown pigmentary blotches, 6 with gray-blue globules, 3 with loss of pigment network Case 2 F, 74 1 2 months 9 8 nevi with brown pigmentary blotches and crust formation, 1 with gray-blue homogenous areas Case 3 F, 30 2 2 weeks 2 1 nevus with brown pigmentary blotches with crust formation, homogenous brown-gray areas and a ‘peppering’ morphology; 1 nevus with a central brown pigmentary blotch and crust formation Case 4 F, 23 7 1 week 1 1 nevus with central brown pigmentary blotch Case 5 F, 18 5 1 week 1 1 nevus with multiple brown mentary blotches and crust formation Figure 1 . (A) Brown pigmentary blotch with crust formation and gray-blue areas. (B) Gray-blue globules and diffuse loss of pigment net- work. (C) Gray-blue globules and central loss of pigment network. (D) Brown pigmentary blotches with crust formation. (E) Diffuse brown pigmentary blotches with crust formation. (F) Gray areas and loss of pigment network. (G) Central brown pigmentary blotch. (H) Multiple brown-black pigmentary blotches with crust formation. (I) Brown pigmentary blotch and central gray-blue area. Research Letter | Dermatol Pract Concept. 2024;14(3):e2024162 3 Conclusions Several studies have revealed that nevi might undergo both clinical and dermatoscopic changes after one or more ses- sions of laser or IPL for unwanted hair removal. Dermato- scopic changes have been reported through small case series and case reports: pigmentary blotches with crust formation [1,4]; pigmentary blotches with subsequent loss of pigment network [5]; asymmetric pigment network with gray-blue dots and milky red veil [6]; blue-gray areas, loss of pigment network and peppering morphology [3]. Histopathological examination showed an increased num- ber of melanophages in the papillary dermis [1,3,5], scale- crust and melanin granules over a reticular stratum corneum [1], scarce nests of nevus cells with significant pigment loss, predominantly perifollicularly [3], increased vascularization, perivascular infiltrate and fibrosis [3,5,6]. Melan-A immu- nostaining revealed normal distribution of epidermal mela- nocytes and the absence of Melan-A dermal melanocytes [4]. Furthermore, regression of nevi has been reported after diode laser [5]. However, histopathology excluded any ma- lignant transformation. Ultraviolet radiation is known to cause DNA damage and mutagenesis, while the effects of visible light and infra- red laser on tissues are primarily thermal. However, we can- not definitively exclude the potential for malignancy after repeated exposure to sublethal laser irradiation and thermal scarring of nevomelanocytes. 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