The hair bulb, isthmus, and infundibulum are the three units that make up the vertical sections of the hair follicle [42-44]. The hair bulb begins at the base of the hair follicle and continues to the insertion of the arrector pili muscle. This portion of the hair is 3-7 mm below the surface of the […]

Melanogensis occurs by a common biochemical pathway in both the hair follicle and the epidermis [26-28]. Two types of melanin are found in the skin and hair, the brown/black melanin, eumelanin, and the red melanin, pheomelanin [26]. The formation of eumelanin begins with either hydroxylation of intracellular L-phenylalanine or from extracellular tyrosine transported into the […]

The differences in skin color are the result of genetic background and environmental exposure to the sun [9-11]. Darker pigmented skin evolved in those whose ancestors lived near the equator [12]. It is widely believed that an increase in skin melanin protected the skin from the ultraviolet light exposure in equatorial locations. Lighter skin color […]

James Henry The Procter and Gamble Company, Cincinnati, OH, USA 8.1 Introduction 196 8.2 Melanin in the Skin 196 8.2.1 Melanogenesis in Skin and Hair 197 8.3 Hair Biology 197 8.3.1 Some Basic Thermal Principles Describing the Response of Hair Follicles to Heat 199 8.4 Side Effects of Laser Hair Removal by Skin Type 200 […]

Hair removal using lasers and light-based methodologies are limited by the chromophore dependence on melanin located in the hair shaft, creating a small window of efficacy and safety for the treatment of light hair hues and darker skin phenotypes. More recently, this dependence on the melanin chromophore has been eliminated by using an alternative source […]

With the advent of combined optical and RF technology, various clinical trials have been conducted to elucidate the potential of the system’s application on different hair types and skin colors by varying the treatment settings, as well as the number of treatments adminis­tered (Table 7.4). Del Giglio and Shaoul [24] conducted a recent multicenter study […]

A number of lasers systems are now available for hair removal (Table 7.2), as the absorp­tion spectrum of melanin within hair follicles extends from the ultraviolet to the near-infrared wavelengths [1,15,23,53]. The most simple classification system divides the lasers according to wavelength: short, intermediate, or long. The laser surgeon must choose a short wavelength technology […]

Neil S. Sadick1 and Rita V. Patel2 department of Dermatology, Weill Medical College of Comell University, New York, NY, USA 2Department of Dermatology, University of Miami Miller School of Medicine, Miami, FL, USA 7.1 Introduction 181 7.2 Principle of Selective Photothermolysis: Combination of RF and Light Energies 183 7.3 Review of Clinical Studies with Combined […]

Lasers represent a major advance in the control of unwanted hair growth. However, the constraints around pigmentation and acceptable energy levels for “in-home” use may con­strain the potential of lasers for widespread commercial success. Thus, the use of chemical technologies in combination with energy-emitting devices may represent an opportunity for meeting the threshold consumer needs […]