AESTHETIC FOCUS Laser and light based hair removal BY PAOLO BONAN, MICHELA TROIANO, NICOLA BRUSCINO Laser hair removal is a popular, and constantly evolving, treatment. Professor Paolo Bonan and colleagues provide us with a comprehensive overview and some ‘top tips’ for how to make the procedure as safe and effective as possible. air removal, also known as removal in these sensitive areas may be during the whole hair cycle. For this epilation, is the deliberate very painful with wax or other traditional reason, targeting the hair follicles during a removal of body hairs. Forms devices, so the employment of a laser or specific growth period, is considered to be Hof hair removal have been light-based technology is often preferred. unimportant. The previous theory about practised in almost all human cultures the greater sensitivity of the anagen period since at least the Neolithic era, for various Lasers and light based hair was due to animal studies which showed a cultural, sexual, medical or religious removal: how they work maximum concentration of melanin within reasons. Methods used to remove hairs Several laser and light devices are available anagen hairs [2-5]. have varied in different times and regions, on the market for hair removal: ruby laser Photomechanical destruction, through including bleaching, plucking, shaving, (694nm), Alexandrite laser (755nm), diode the generation of shockwaves, has been waxing, threading, chemical depilatories used by nanosecond Q-switched lasers, laser (800nm), intense pulsed light (IPL) (eflornithine) and electrolysis; these employed during the early phase of laser (590-1200nm), neodymium-doped:yttrium methods can no longer be considered hair removal several years ago; these lasers aluminium garnet laser (Nd:YAG) (1064nm) ideal tools because of the limited and the are no longer considered because they and light-based devices for home use. short-term efficacy. There has, therefore, result in temporary hair loss. The purpose of these devices is the developed a great demand for efficient Photochemical destruction, through damage of stem cells in the bulge and long-term hair removal systems; in fact, the creation of toxic mediators such as dermal papilla of the hair follicle by photoepilation by light and laser-based singlet oxygen or other free radicals, is targeting melanin which represents the systems is one of the fastest growing areas the approach followed by photodynamic specific chromophore [1-3]. Melanin of cosmetic dermatology. therapy (PDT); this could be a potential absorbs wavelengths between 600-1100nm, Only a few patients require hair removal alternative technology since it may also the recommended optical window for for a purely medical purpose (these work on non-pigmented hairs. hair removal with the destruction of the include patients affected by hirsutism, follicular unit. hypertrichosis, acne cheloidalis nucae, Lasers and lights For such devices, three main pseudofolliculitis barbae), while most mechanisms of action have been undergo these procedures for purely IPL suggested: photothermal destruction, aesthetic reasons, mainly for the removal of IPL technology uses a xenon broadband photomechanical damage and unwanted hair from the face, trunk, limbs flashlamp to generate non-coherent photochemical process. and genital area. light in a spectrum between visible and Photothermal destruction of hair follicles If patients are affected by medical near infrared (500-1200nm). To reach the constitutes the fundamental concept of troubles, they are highly motivated and desired chromophore, filters cut out the generally willing to undergo long and hair removal: melanin, the chromophore light emission according to the wavelengths painful procedures; when the approach contained inside the hair shaft, absorbs required by the physician; consequently, is purely aesthetic, discomfort levels and the light energy converting it into heat, this type of light source can excite more the session’s duration can be important which spreads to the nearby bulge non- than one chromophore (haemoglobin, factors for the choice of the device and the pigmented stem cells, the target. The melanin, water). Handpieces have a large pathway of treatments. transfer of heat from the chromophore to surface of the spot, which is generally In particular, the genital zone is one the target is necessary for the effectiveness cooled, and application of gel on the skin of the most commonly treated body of the treatment. Recently it has been surface is required during epilation. Clinical areas; the so-called ‘Brazilian look’, which demonstrated that the anagen phase is endpoints, frequently seen during epilation involves complete removal of hairs from sensitive to laser and light pulses exactly by lasers, are not commonly observed with the vulva, perineum, anus, and buttocks, is as in the catagen and the telogen since IPL. Various studies have shown that IPL is a particularly popular current trend. Hair in humans the hairs remain pigmented inferior to Alexandrite and Nd:YAG lasers for long-term results [6-14]. Nd:YAG Nd-YAG long pulse is a laser source with “During the treatment, the laser / light emission should a longer wavelength and represents the first choice in darker skin patients always be matched with a cooling system” in our experience. According to several pmfa news | APRIL/MAY 2017 | VOL 4 NO 4 | www.pmfanews.com AESTHETIC FOCUS Figure 1A: Before starting laser hair removal on the inguinal areas. 1B: The results achieved after two Alexandrite laser sessions (Motus AX, Deka M.E.L.A. laser, Elen, Italy). comparative studies Nd:YAG laser has been with melanin it is particularly indicated in the American market. Side-effects, like found to be less effective than Alexandrite in patients with low phototypes (up to hypopigmentation, have been reported and diode lasers, and more efficacious than 3-4) for the risk of burning resulting in after its use on dark skin. IPL and ruby laser as regards long-lasting hyper or hypo pigmentation. In order to hair removal results [6-14]. remedy this problem a new technology for Home devices photoepilation has recently been proposed. Home devices are characterised by lower Diode laser A new handpiece, with a cooled sapphire fluence compared with medical devices; Histological studies showed significant cylinder tip that conveys the laser beam this feature limits their effectiveness, since reduction in hair density and thickness onto the patient’s skin, has been introduced there is evidence of the capability of hair in skin treated with longer pulse 810nm onto the market. The use of this sapphire removal systems being fluence-dependent. diode laser. The long pulsed diode has guide dramatically reduces the system Conversely, the risks of adverse effects are been greatly used for hair removal due energy leaks to the skin, thus increasing reduced too. Nevertheless, the general to the efficacy and safety in patients with effectiveness of the laser transmission public often prefer investing their money Fitzpatrick skin phototypes I-V. Such lasers as never before (Figure 1). Working at low into these tools because they are cheap and are usually employed through an in-motion fluences makes the treatment painless pain free. manner, with several short pulses and a without undesirable side-effects. Repeated high frequency. Patients often consider this passages over the same area makes the Clinical features of the patient laser more tolerable than the long pulsed treatment uniform without leaving any area The main features to be evaluated are skin Nd:YAG [6-14]. untreated. phototype and hair. Shorter wavelengths are more absorbed by melanin, so for high Alexandrite laser Ruby laser phototypes lasers with a low wavelength Since 1997 the long pulse 755nm This was the first laser device selectively will result in a greater risk of burning and Alexandrite laser has been utilised with employed for hair removal, by Grossman consequently other unpleasant side- efficacy in laser hair removal. It allows in 1996 [15]. Compared to newer laser and effects; for these patients the selection of a deep penetration into the dermis light-based modalities, the ruby laser is a diode laser or Nd:YAG laser is mandatory. allowing it to act on fair and black hair, less effective and in fact there are no long If the physician has a limited choice of however, because of its competition pulsed ruby lasers commercially available laser systems, it is possible to use a lower fluence, a longer pulse duration and a specific filter to make the treatment safer. Table 1: Contraindications to laser / light hair removal. Sometimes, for various reasons, patients cannot be treated with lasers or IPL devices Extreme tan Laser sessions should be delayed until the tanning has faded. (Table 1). Lack of melanin Poor results for blonde, white, grey hairs. Endocrine abnormalities May make the laser / light based treatments less effective. Preparation for the treatment Pregnancy No evidence of possible risks, but the treatment is not It is necessary to remind the patient to recommended for potential legal issues. avoid all epilation techniques for two to four weeks before the laser / light Autoimmune connective High photosensitivity. hair removal, otherwise it will provoke diseases elimination of the structure target of the Dermatological disorders Psoriasis, lichen planus and vitiligo may be triggered by a laser photoepilation. Shaving the hair by the with Koebner phenomenon / light employment. physician immediately before the beginning History of hypertrophic scars The laser / light sessions can evoke an impaired tissue repair of the treatment, or two to three days and keloids and subsequently scars and keloids. earlier by the patient, is adequate. If the Gold intake It can cause chrysiasis with cutaneous diffuse laser / light hair removal is not preceded by hyperpigmentations. shaving, the pulses absorbed by the long hairs could induce burning of the skin. We Isotretinoin Six to 12 months of washout time after oral isotretinoin, usually prefer to do the shaving ourselves, otherwise there are risks of skin fragility, delay in since we can better evaluate the diameter reepithelisation, hyperpigmentations and scars.