Open AccessLaser management for congenital dermal melanocytosis
Author(s) -
Igor Ponomarev,
Людмила Диевна Шакина
Publication year - 2020
Publication title -
rossijskij pediatričeskij žurnal
Language(s) - English
Resource type - Journals
eISSN - 2413-2918
pISSN - 1560-9561
DOI - 10.18821/1560-9561-2020-23-2-132-137
Subject(s) - dermis , laser , absorption (acoustics) , epidermis (zoology) , radiation , materials science , dermatology , hyperpigmentation , melanin , nd:yag laser , optoelectronics , biomedical engineering , optics , biophysics , chemistry , pathology , medicine , anatomy , biology , biochemistry , physics , composite material
Congenital dermal melanocytosis (CDM) is a malformation of the dermis caused by antenatal impairment of melanogenesis. There are considered data on the epidemiology, history of the study, the characteristics of the pathogenesis and clinical picture of CDM. Data on the efficacy and side effects of treatment of CDM with ruby, alexandrite and neodymium laser in children and adults are compared. The effectiveness of laser treatment for CDM is closely related to the value of the integral absorption of radiation by targeted photothermophores of the epidermis and dermis: melanin, oxyhemoglobin and reduced hemoglobin. The safety of laser exposure is determined by its selectivity, which directly depends on the ratio between the absorption of radiation by the main target photothermophores and water. For the first time, integral indices of the absorption of laser radiation in the pathological focus area by the main photothermophores of the epidermis and dermis (oxyhemoglobin, reduced hemoglobin, as well as the melanin content and localization of ectopic melanocytes in the reticular layer of the dermis) and water are presented. In the CDM involved area, the integrated coefficients of absorption by the main target photothermophores of radiation with a wavelength of 511 nm and 578 nm were shown to be much higher, and the absorption by water is much lower than for radiation with a wavelength of more than 600 nm generated by a ruby, alexandrite or neodymium laser. The described pathogenetic features of laser skin biophotonics upon exposure of the CDM region to the radiation with a wavelength of more than 600 nm increases the risk of the development of such characteristic side effects as hyperpigmentation, deterioration of the collagen structure of the dermis with subsequent formation of scars in the postradiated area. To ensure the complete elimination of ectopic melanocytes and minimize the risk of side effects during laser surgical treatment of CMD area, it is advisable to use the two-wavelengths radiation generated by the copper vapor laser: with a wavelength that is maximally absorbed by melanin (511 nm) and with a wavelength with high absorption of both oxyhemoglobin and hemoglobin (578 nm), but with negligible absorption by water.