Permanent Hair Removal by Normal-Mode Ruby Laser
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OBSERVATION Permanent Hair Removal by Normal-Mode Ruby Laser Christine C. Dierickx, MD; Melanie C. Grossman, MD; William A. Farinelli; R. Rox Anderson, MD Objective: To assess the permanence of hair removal after laser exposure, 4 participants still had obvious, sig- by normal-mode ruby laser treatment. nificant hair loss at all laser-treated sites compared with the unexposed shaved and wax-epilated control sites. In Methods: Hair removal was measured for 2 years after all 4 participants, there was no significant change in hair a single treatment with normal-mode ruby laser pulses counts 6 months, 1 year, and 2 years after laser expo- (694 nm, 270 microseconds, 6-mm beam diameter). sure. Laser-induced alopecia correlated histologically with miniaturized, velluslike hair follicles. No scarring and no Observations: Six test areas on the thighs or backs of permanent pigmentary changes were observed. 13 volunteers were exposed to normal-mode ruby laser pulses at fluences of 30 to 60 J/cm2 delivered to both Conclusions: Permanent, nonscarring alopecia can be shaved and wax-epilated skin. In addition, there was a induced by a single treatment with high-fluence ruby la- shaved and wax-epilated control site. Terminal hairs were ser pulses. Miniaturization of the terminal hair follicles manually counted before and after laser exposure. Tran- seems to account for this response. sient alopecia occurred in all 13 participants after laser exposure, consistent with induction of telogen. Two years Arch Dermatol. 1998;134:837-842 NWANTED HAIR is a ma- hair growth delay consistent with induc- jor cosmetic and surgi- tion of telogen. Ruby lasers have been com- cal problem. Many tem- mercialized for hair removal, but the ques- porary hair removal tion remains whether permanent hair loss methods exist, includ- can be induced by selective photother- ing shaving, wax epilation, and use of molysis. Four study participants6 had clini- U 1,2 chemical depilatories. Electrolysis is a cally obvious hair loss at the final fol- well-established method for permanent de- low-up visit 6 months after exposure, each struction of terminal hair follicles. How- of these with less than 50% regrowth of ever, the method is tedious, and efficacy terminal hairs. We decided to follow up has been reported to range from 15% to the participants of this first study at 1 and 50% permanent hair loss.3 Scarring can oc- 2 years after laser exposure to evaluate the cur after electrolysis, especially if inex- permanence of hair removal. pertly performed.4 RESULTS For editorial comment see page 867 HAIR LOSS Results at 6 months’ follow-up have been Damage to hair follicles based on the published previously6 but did not ad- 5 theory of selective photothermolysis has dress the question of permanent hair been reported recently.6 Thirteen volun- From the Wellman Laboratories loss. Of the 13 participants, 7 were fol- teers with brown or black hair were ex- lowed up for 2 years after laser exposure. of Photomedicine, Harvard posed to normal-mode ruby laser pulses Medical School, Boston, Mass (694 nm, 270 microseconds, 6-mm beam (Drs Dierickx and Anderson 2 and Mr Farinelli), and the diameter) at fluences of 30 to 60 J/cm de- livered to both shaved and wax-epilated This article is also available on our Laser and Skin Surgery Center Web site: www.ama-assn.org/derm. of New York City, New York, skin sites on the thighs or back. In all 13 NY (Dr Grossman). participants, laser exposures produced a ARCH DERMATOL / VOL 134, JULY 1998 837 ©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 PARTICIPANTS AND METHODS DATA ANALYSIS Hair loss was defined as the percentage of terminal hairs Thirteen adult volunteers (12 men and 1 woman) con- absent after treatment compared with the number before sented to participate, as previously described.6 All had treatment. For each site, at each follow-up visit, hair loss fair skin (Fitzpatrick type I, II, or III) and brown or was calculated. Results for each experimental condition black hair. Test sites were chosen on the back or poste- were pooled for all participants. The mean ± SD for each rior aspect of the thighs based on uniformity and density condition was calculated. A paired t test was used to of terminal hairs. Eight 3 3 2-cm areas were mapped and determine significant differences (P,.05) between post- photographed. Baseline hair counts were obtained from treatment and pretreatment hair counts for each experi- each site by manually counting and marking terminal mental condition at the 6-, 12-, and 24-month observa- hairs. Before laser exposure, half of the test sites were tion times. shaved and half were epilated with cold wax (My-Epil, Laboratoire Suzy, Montreuil, France). Sites were irradi- LASER AND DELIVERY APPARATUS ated with a normal-mode ruby laser, described below, at fluences of 0 (unexposed control), 30, 40, and 60 J/cm2. A normal-mode, flashlamp-pumped, 694-nm ruby laser Laser pulses were given in a contiguous, nominally with a 270-microsecond pulse duration and a 6-mm spot- nonoverlapping pattern that covered the entire test site. size was used (model 936R4H-2, Lasermetrics, Winter Clinical evaluation, terminal hair counts, and pho- Park, Fla). The beam was steered via an articulated arm tographs were obtained 1, 3, 6, 12, and 24 months after into an actively cooled “hand piece” designed to maxi- laser exposure. One participant who had obvious alope- mize delivery of light into the reticular dermis while mini- cia in all laser exposure sites at all of these follow-up vis- mizing epidermal injury. A planoconvex sapphire lens its consented to biopsy examination. Three-millimeter (approximately 20-mm focal length) was used to provide punch biopsy samples were obtained before treatment a convergent beam at the skin surface and to increase and at 1 year after laser exposure from a site with alope- beam coupling into the skin compared with air as an cia treated at 60 J/cm2 after shaving. Tissue specimens external medium. The sapphire lens was cooled to 4°C to were processed for light microscopy of horizontal sec- provide heat conduction from the epidermis before, dur- tions with a technique using trisection or quadrisection ing, and after each laser pulse. The convex surface of the that maintains all sections in the same anatomic orienta- cold sapphire lens was pressed firmly against the skin tion (deep to superficial) on the microscope slides.7 All before delivery of each laser pulse. Delivered pulse energy specimens were stained with hematoxylin-eosin for light into air was measured with a laser energy meter (model microscopy. 351, Scientech, Boulder, Colo). At 1 year and 2 years after laser treatment, 4 of these 7 in the shaved sites for all fluences compared with the participants still had obvious hair loss confined to laser- untreated control site. treated sites and 3 had complete or nearly complete hair regrowth. In all 7 participants, there was no significant HISTOLOGICAL FINDINGS change in terminal hair counts 6 months, 1 year, and 2 years after laser exposure. Terminal and velluslike (miniaturized) hairs were iden- Figure 1, left, illustrates hair loss on a partici- tified on the transverse sections and counted by estab- pant’s back 1 year after laser exposure. The hair loss is lished criteria.8-10 Terminal-velluslike hair ratios were fluence dependent, with the greatest loss at the highest calculated from the follicular counts, and fibrous tracts fluence (60 J/cm2). Figure 1, right, illustrates the same were recorded as absent or present. Results are shown sites 2 years after treatment. The same amount of hair in the Table. The total number of hairs was identical in loss is still present. Figure 2, top and bottom, show the control and laser-treated sites. However, in the the same site on an upper thigh treated with 60 J/cm2 laser-treated sites, there was a reduction in large termi- at 3 months and 2 years, respectively. No substantial nal hairs with a reciprocal increase in small velluslike change in the clinical appearance of the alopecia is hairs. The average hair shaft diameter measured from seen. Neither pigment changes nor scarring was seen the histological sections also decreased after laser treat- in any participant at the 12- and 24-month follow-up ment (Figure 4). There were no signs of fibrous tracts, visits. and normal-appearing sebaceous glands were still pre- Hair loss at 6, 12, and 24 months after a single sent around the miniaturized hair follicles. laser exposure in the 4 participants showing perma- nent hair loss are plotted vs fluence in Figure 3. Sites COMMENT treated with 60 J/cm2 (highest fluence) after shaving had the greatest hair loss, 64.3% ± 1.1%. Statistically The results of this study show that permanent loss of significant hair loss was seen at 6 months for all flu- terminal (coarse) hair can result from a single treat- ences at both shaved and epilated sites compared with ment with high-fluence, normal-mode ruby laser the unexposed shaved and epilated control sites. At 1 pulses. The lack of change in any participant’s termi- year and 2 years, there was significantly less hair only nal hair counts beyond 6 months after laser exposure ARCH DERMATOL / VOL 134, JULY 1998 838 ©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 Figure 1. Left, Test sites on the back 1 year after ruby laser treatment. Site 1 was treated with 30 J/cm2, site 2 was treated with 40 J/cm2, and site 3 was treated with 60 J/cm2.