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Laser Hair Removal in Dark-Skinned Patients

Lasers have revolutionized our ability to permanently reduce hair growth in fair-skinned individuals with dark hair. The first long-pulsed devices developed for laser hair removal (long-pulsed ruby and alexandrite lasers) had limited efficacy in dark-skinned patients because the wavelengths were too well absorbed by cutaneous pigment or because the pulse durations were too short to spare epidermal pigment. Adverse effects -- temporary hyperpigmentation and permanent hypopigmentation -- limited use of these lasers in patients with skin types IV, V, and VI. Development of long-pulsed Nd:YAG lasers, which are less well absorbed by pigment and have longer pulse durations, has increased the scope of laser hair removal to include all skin types.

In this study, 20 women with skin types IV to VI and dark brown or black hair on the face, axilla, or legs received three long-pulsed 1064 nm Nd:YAG laser treatments at pulse durations of 50 ms and fluences of 40 to 50 J/cm². Patients were treated at monthly intervals. Independent assessors compared before- and after-treatment photographs taken at each session and evaluated photos taken at 1, 3, 6, and 12 months after the last treatment. Substantial hair reduction was seen after each treatment session; a sustained reduction of 70 percent to 90 percent was noted 12 months after the last treatment. Axillary hair was the most responsive. Patients found the treatment uncomfortable but tolerable. Five percent of treatments induced transient hyperpigmentation that lasted an average of 4 weeks.

Comment: This prospective study confirms that long pulses of Nd:YAG laser light effectively remove hair in even very dark-skinned individuals. Long pulses of 1064-nm laser light are absorbed well enough to cause follicular damage but not well enough by epidermal melanin to significantly alter skin pigment. The long-pulsed Nd:YAG laser appears to inhibit hair regrowth in dark-skinned patients at least as well as long-pulsed alexandrite or ruby lasers do in fair-skinned individuals with dark hair. Because the long-pulsed Nd:YAG laser also permanently reduces hair growth in these fair-skinned patients, it can be considered effective against dark hair in patients of any skin type.

— JS Dover

Published in Journal Watch Dermatology October 24, 2001

Citation(s):

Alster TS et al. Long-pulsed Nd:YAG laser-assisted hair removal in pigmented skin: A clinical and histological evaluation. Arch Dermatol 2001 Jul 137 885-889.

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