Hair Removal in Darker Skin Types Using Light-Based Devices

James Henry

The Procter and Gamble Company, Cincinnati, OH, USA

Gurpreet S. Ahluwalia (ed.), Cosmetic Applications of Laser and Light-Based Systems, 195-215,

© 2009 William Andrew Inc.

7.2 I ntroduction

Laser hair removal allows a physician or trained professional to treat large areas of the body quickly, with long-lasting or permanent reduction in hair growth [1]. These reductions in growing hair are caused by the interaction of the laser with the hair melanin. While initially developed for the ideal contrast of dark hair against a fair skin background, an increasing demand is foreseen to treat all individuals regardless of base skin color, particularly in the United States, where the population is becoming more ethnically diverse [2,3]. Significant hair growth reduction has been reported in people with darker skin types; however, the inter­action of the laser with skin melanin must be taken into account to prevent long-lasting side effects [3-5]. Permanent changes in pigmentation and skin texture, focal atrophy, and scar­ring are some of the adverse effects that have been reported with improper laser use [6]. As the understanding of the variations in response in people of color to the laser grows, these side effects associated with laser hair reduction can be reduced [7,8]. This chapter will discuss melanogenesis in skin and hair follicle, how melanin granules or melanosomes are formed, some basic thermal principles describing how hair follicles respond to heat, the relevance of using the Fitzpatrick scale, various cooling systems designed to protect the epidermis, and the efficacy and safety of various lasers and IPL systems for darker skin types.