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Maintenance therapy typically required after laser hair removal



SAN DIEGO – Hair removal ranks as the most popular laser procedure performed in the United States, but patients with blond, red, or gray hairs are out of luck, since those threadlike strands lack a chromophore for the laser to respond to.

“For now, I recommend that these patients get electrolysis or use eflornithine cream,” Arisa Ortiz, MD, said at the annual Masters of Aesthetics Symposium.

Future treatment options for patients with light-colored hair look promising, however. One emerging technology combines laser hair removal with the insertion of a silver nanoparticle into the unpigmented hair follicle. “These are currently in pivotal trials, so we should be seeing them on the market very soon,” she said.

According to Dr. Ortiz, director of laser and cosmetic dermatology in the department of dermatology at the University of California, San Diego, there is still a place for nonlaser hair removal, including shaving, waxing, threading, and electrolysis, but laser hair removal is safe, effective in skilled hands, and permanent. Key factors in optimizing treatment include understanding laser safety and laser-tissue interaction, proper patient selection, preoperative preparation, parameter selection, and recognizing complications.

Dr. Arisa Ortiz

Dr. Arisa Ortiz

The first-degree target in laser hair removal is eumelanin contained in the bulb of hair follicles, she said, but the heat must diffuse to a secondary target – follicular stem cells in the bulge of the outer root sheath. “Pulse duration is important,” she said. “The thermal relaxation time of a terminal hair follicle is roughly 100 milliseconds. Longer pulse widths are going to be safer for darker skin types, and you want shorter pulse durations for fine hair, and longer pulse durations for thicker hair. Spot size is also important. Larger spot sizes are faster and create less pain and less epidermal damage.”

Indications include unwanted hair, hypertrichosis, and hirsutism/polycystic ovary syndrome (PCOS). “You want to counsel patients with PCOS properly, because they will require multiple treatments as they tend to make new hair follicles,” she said. Other indications include ingrown hairs, pseudofolliculitis barbae, and pilonidal cysts.

The best candidates for laser hair removal are patients who have a light skin color and dark hair, and those who have thick, coarse hair. “Be cautious when treating tanned patients, and adjust your setting to a longer pulse duration and a lower fluence,” she continued. “I tell (patients) they’ll likely need at least six treatments. You want to treat them every 6 to 8 weeks. If you do treatments sooner than that, it’s probably not cost effective for the patient, because of the way hair follicles cycle. It’s also important that they avoid the sun.”

Clinicians can achieve temporary hair removal with Q-switched lasers, which may be suitable for patients with pseudofolliculitis barbae but who may not want permanent hair removal. “This will just vaporize the actual hair follicle, but that heat is not extending to the stem cells, so it’s temporary hair removal, because the hair follicle transitions into the telogen phase,” Dr. Ortiz explained. “The hair will then grow back after a few months.”

Endpoints are the most important factor for laser hair removal. You want to see perifollicular erythema, perifollicular edema, or hair singeing. “Then you know you have an effective treatment setting,” she said. “Sometimes, however, it takes time for this erythema or edema to develop, so you don’t want to keep increasing your fluences to see this end point. If you’re not comfortable with the laser you’re using, I recommend waiting a few minutes after treatment, and looking for the end point. You could always go higher during the next treatment, if you need to.”

Higher fluences have been correlated with greater permanent hair removal, but also with more side effects. “The recommended treatment settings are going to be the highest possible tolerated fluence that yields the desired endpoint without any adverse effects,” Dr. Ortiz said.

The first hair removal laser to hit the market was the Ruby 694-nm laser, which is safe for Fitzpatrick skin types I-III. A long-term follow-up of the seminal study showed permanent posttreatment efficacy of up to 2 years (Arch Dermatol. 1998;134[7]:837-42). The Alexandrite 755-nm laser, meanwhile, penetrates deeper because it’s a longer wavelength, so there’s less melanin absorption, and it’s safer for darker skin types. “With a device like this, you want to make sure that you’re always holding the laser perpendicular to the skin surface so that your cryogen spray is firing at the same area as the laser. [That way] you don’t get a burn injury,” she said.

The diode at 800 nm and 810 nm penetrates even deeper, which results in less melanin absorption. “Originally these devices had smaller spot sizes, but now some of the newer devices have larger hand pieces and use contact cooling,” she said. “Some of the diode lasers cause singeing and char. The carbon actually sticks onto the sapphire window of the device, so you want to make sure you swipe the window after every few pulses so that you’re not putting the char onto the epidermis and causing an epidermal burn,” Dr. Ortiz advised.

She described the Nd:YAG 1,064-nm laser as the safest for skin types V and VI. It has the deepest penetration but the least melanin absorption. Intense pulsed light (IPL) can also be used for hair removal. IPLs “have a larger spot size, and you can use various cutoff filters to make them safer for darker skin types,” she said. “However, in head-to-head studies, usually laser hair removal does better than IPL.”

Potential complications from laser hair removal include paradoxical hypertrichosis; pigmentary alterations such as hyperpigmentation or hypopigmentation; infections/folliculitis, scarring, and eye injury. Dr. Ortiz underscored the importance of counseling patients about the need for maintenance treatments prior to initiating their first hair removal session. Laser hair removal removes about 85-90% of hairs permanently “so that leaves a significant number that remain, and new hairs may grow over time,” she said.

Authors of a recent study found that the plume release during laser hair removal should be considered a potential biohazard that warrants the use of smoke evacuators and good room ventilation (JAMA Dermatol. 2016;152[12]:1320-26). “We are learning that we should be more careful to evacuate the plume from laser hair removal or wear laser protective masks as the plume may contain harmful chemicals that we breathe in on a daily basis,” said Dr. Ortiz, who was not affiliated with the analysis.

She disclosed serving as a consultant to, receiving equipment from, and/or being a member of the scientific board of several device companies, including Alastin, Allergan, BTL, Cutera, InMode, Merz, Revance, Rodan and Fields, Sciton, and Sienna Biopharmaceuticals.

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