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 optima l parameters and treatment protocols remain largely unknown. In this study, the histopathological changes in the hair follicles after long pulsed alex andrite laser irradiation are discussed and the clinical application of irr adiation energy at the time of treatment is described. The laser used in th is study is equipped with a computer controlled cooling device. A histopath ological study was performed to compare the differences in the degree of de generation in the epidermis and follicles treated with and without the cool ing 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 we re present were observed. The results of this study strongly indicate the e fficacy of a long-pulsed alexandrite laser equipped with a computer control led cooling device for clinical depilation.