Histopathological changes in hair follicles after irradiation with a long-pulse alexandrite laser equipped with a cooling device

Several laser systems are currently used for epilation. However, the optimal parameters and treatment protocols remain largely unknown. In this study, the histopathological changes in the hair follicles after long pulsed alexandrite laser irradiation are discussed and the clinical application of irradiation energy at the time of treatment is described. The laser used in this study is equipped with a computer controlled cooling device. A histopathological study was performed to compare the differences in the degree of degeneration in the epidermis and follicles treated with and without the cooling device. In comparison with normal hair papilla, in the laser irradiated skin, injury of melanin containing cells and hair shafts and external root-sheaths in the periphery were observed, while the epidermis was completely protected by the cooling device. The condition of the hair papilla of the tissue irradiated at a fluence of 25 J/cm(2) with a spot diameter of 15 mm and 20 J/cm(2), with a spot diameter of 18 mm were investigated thoroughly. Swollen papilla and selective destruction of the site where melanocytes were present were observed. The results of this study strongly indicate the efficacy of a long-pulsed alexandrite laser equipped with a computer controlled cooling device for clinical depilation.