ABSTRACT
The use of laser and light devices has revolutionized the treatment of unwanted hair in the last decade. Various systems have been found effective for photoepilation of black to brown hair. However, for a particular segment of the population with light, blond, and red hair, safe and effective hair reduction has been difficult to achieve using the current technology. The reason for this challenge is the premise for photoepilation. Most available systems operate on the basis of the principle of selective photothermolysis. Discriminate targeting of the hair follicle apparatus by laser and non-laser light sources is achieved when optical energy of sufficient quantity to produce thermal damage is selectively absorbed by the follicle by virtue of the chromophore differential between it and the surrounding cutaneous tissue. The chromophore in this case is melanin found within the hair shaft, follicular epithelium, and the hair matrix. Nevertheless, the surrounding tissue may be heated significantly in the process of dissipation of this optical energy. Thus, the
(1) Photoepilation of light hair is significantly more challenging than that of dark hair
(2) The application of exogenous liposomal melanin may temporarily augment the naturally occurring follicular melanin chromophore, and thus enhance laser photoepilation
(3) The use of radiofrequency technology in conjunction with a light-based source system provides enhanced epilation by combining the principles of selective photothermolysis and electrothermolysis
(4) Phototodynamic therapy (PDT) may provide the best chance of removing non-pigmented hairs
effectiveness of any system depends largely on the amount of melanin present within the follicle, and its safety or the relative lack thereof in the surrounding skin. Consequently, the selectivity becomes increasingly elusive as the target hair considered for epilation becomes comparably less melanized in comparison with the surrounding skin.
