Guidelines for laser hair removal

Laser-Induced Koebner-Related Skin Reactions: A Clinical Overview

The Koebner phenomenon (KP), also known as the isomorphic response, describes the process by which new lesions that are clinically and histologically identical to a patient's existing skin disease develop following trauma. Many skin diseases exhibit this characteristic, with variations that include possible, questionable, and pseudo-Koebner reactions, with the latter category occurring due to infectious agents seeding at a trauma site. Laser application, a type of controlled skin injury used for improving cutaneous lesions and skin rejuvenation, is also considered a form of trauma. This raises the question of whether controlled thermal injury can be regarded as a type of mechanical trauma capable of producing Koebner-related reactions. We conducted a literature review of cases or studies to identify laser-induced dermatoses that correspond to Koebner-related or pathergy reaction categories. As a whole, we identified nine case reports on true KPs, two cases on possible KPs, seventeen cases on laser-induced questionable KPs comprising cases of vasculitis, eczema or Meyerson reactions, and eruptive squamous atypia cases (ESA) as well as two pseudo-Koebner cases involving wart occurrences at laser application sites. Laser-induced Koebner reactions highlight several aspects of the KP. Firstly, the type of mechanical damage influences disease promotion, as different lasers are associated with different KPs. For example, hair removal lasers are linked with true and questionable KPs such as vasculitis while resurfacing lasers were found to be more connected with ESA occurrence. Secondly, the laser target is significant, with vascular laser application for port-wine stains tending to result in eczematous reactions, while hair follicle destruction can frequently lead to true KPs. Thirdly, the number of sessions matters; true KPs and eruptive squamous atypia questionable KPs typically appear after one to two sessions, whereas eczematous reactions require more sessions (at least four). Additionally, skin phototype is crucial, with darker phototypes showing a higher KP frequency as laser treatment for hypertrichosis relies on melanin absorption in the hair bulge or bulb for follicle destruction, as chromophore competes with the abundant melanin in the epidermis. Further research with larger-scale studies into trauma-specific Koebner reactions is vital for refining treatment protocols, minimizing post-laser adverse effects, and improving dermatological care outcomes.

Comparing Traditional and “In-Motion” Intense Pulsed Light Techniques for Hair Removal: A Split Study

Background and Objectives: Hair removal is a common aesthetic concern for patients referred to dermatologists and aesthetic physicians. Lasers and lights are one of the mainstays in the management of this condition. Among these devices, intense pulsed lights (IPLs) are broadly used in order to reduce the number and width of the hair present. Currently used techniques are associated with a high risk of side effects, such as hyper or hypopigmentation. Materials and Methods: Thirty patients seeking hair removal in one or more body areas with skin phototypes 1 to 4 were recruited to perform this study. All areas to be treated were divided into two equal regions; one side was treated with the standard IPL hair removal procedure, while the other was treated with a new “in-motion” IPL technology. Results and hair removal rates were evaluated six months after the last treatment. Results: Out of the 30 patients treated, all patients experienced hair reduction. No statistically significant difference in hair removal was noted among the two sides. A statistically significant reduction in pain during the procedure was observed in the side treated with the “in-motion” technique. Conclusions: Traditional and “in-motion” IPL techniques have similar results in hair removal; the “in-motion” technology seems to guarantee a better safety profile than the traditional technique, as well as maintains the same results over time and a faster treatment time. A more extensive clinical study will be necessary to confirm our study’s results.

Comparing Traditional and in Motion Nd:YAG Laser in Hair Removal: A Prospective Study

Background and Objectives: Hair removal is a common cosmetic problem interesting more and more patients nowadays. Various laser treatments are currently available. Alexandrite and Nd:YAG laser are the most effective procedures in lighter and darker skin phototypes, respectively. Materials and Methods: A total of 40 patients seeking hair removal in one or more body areas with skin phototypes 2-6 was recruited to perform this study. Patients were divided into two groups. One group was treated with the standard Nd:YAG hair removal procedure, while the other group was treated with a new "in motion" Nd:YAG technology. Results and hair removal rates were evaluated six months after the last treatment. Results: Out of 40 patients treated, all patients experienced hair reduction. No statistically significant difference in hair removal was noted between the two groups; however, a statistically significant reduction in pain during the procedure was observed in the group treated with the "in motion" technique. Conclusions: While traditional and "in motion" Nd:YAG techniques have similar result outcomes in hair removal, the "in motion" technology seems to guarantee a better safety profile compared with the traditional technique. A more extensive clinical study will be necessary to confirm our study's results.

Quantitative characterization of 3D structure of vellus hair arrector pili muscles by micro CT

BACKGROUND

Vellus hair is the fine, wispy hair found over most of the body surface, and the arrector pili muscles (hair muscle) serve to raise these hairs. Hair muscles are also critical for skin regeneration, contributing to the maintenance of stem cells in epidermis and hair follicles. However, little is known about their fundamental properties, especially their structure, because of the limitations of conventional two-dimensional histological analysis.

OBJECTIVES

We aimed to quantitatively characterize the structure of vellus hair muscles by establishing a method to visualize the 3D structure of hair muscle.

METHODS

We observed young female abdominal skin specimens by means of X-ray micro CT and identified hair muscles in each cross-sectional CT image. We then digitally reconstructed the 3D structure of the hair muscles on computer (digital-3D skin), and numerically evaluated their structural parameters.

RESULTS

Vellus hair muscles were clearly distinguished from the surrounding dermal layer in X-ray micro CT images and were digitally reconstructed in 3D from those images for quantification of the structural parameters. The mean value of number of divisions of vellus hair muscles was 1.6, mean depth was 943.6 μm from the skin surface, mean angle to the skin surface was 28.8 degrees, and mean length was 1657.9 μm. These values showed relatively little variation among subjects. The mean muscle volume was approximately 20 million μm³ but showed greater variability than the other parameters.

CONCLUSION

Digital-3D skin technology is a powerful approach to understand the tiny but complex 3D structure of vellus hair muscles. The fundamental nature of vellus hair muscles was characterized in terms of their 3D structural parameters, including number of divisions, angle to the skin surface, depth, and volume.

Expanded scalp flap combined with laser hair removal to reconstruct facial defects around the hairline

BACKGROUND

Congenital and acquired facial lesions around the hairline can bring huge physical and psychological trauma to patients. At present, reconstruction of this area remains a challenge. In this study, we present an alternative technique to reconstruct the aesthetic units using an expanded scalp flap combined with laser hair removal.

METHODS

We retrospectively reviewed 25 cases of facial lesions around the hairline reconstructed with this surgical technique between May 2014 and May 2020. Expander was implanted under the scalp as designed before the operation. After the expander was fully expanded, the lesion was removed and the scalp flap was transferred. Laser hair removal was performed on the transplanted skin flap 2 weeks after flap transfer.

RESULTS

There were ten cases of postburn scar, nine cases of congenital nevus, four cases of traumatic scar, one case of haemangioma, and one case of nevus sebaceous. The median times of laser treatment was 3 (range, 1-8). The median follow-up time was 11 months, ranging from 1 to 27 months. The colour and texture of expanded flaps were similar to adjacent tissue in all cases. The direction of reserved hair in transferred flaps was consistent with the direction of hair in the recipient area or contralateral hair. There were no complications, such as infection, blistering, discolouration, and ulceration. All patients were satisfied with the appearance of the reconstructed hairline and the surgical outcomes.

CONCLUSIONS

The expanded scalp flap combined with laser hair removal is a feasible and effective technique to reconstruct both sides of the hairline simultaneously from a single donor site with a good colour match and a similar texture and thickness.

Ultrafine particle concentrations during laser hair removal: Effectiveness of smoke evacuators

BACKGROUND AND OBJECTIVES

Laser smoke is a biohazard that contains potentially dangerous toxic and biological components. In laser hair removal (LHR), practitioners undergo prolonged exposure as this procedure is widely used without protective measures. Little is known about the effect of smoke evacuators on ultrafine particle concentrations during LHR. This study aims to assess the effect of different laser devices and different smoke evacuators on the ultrafine particle concentrations in the room during LHR.

STUDY DESIGN/MATERIALS AND METHODS

In a prospective observational study, we included patients with skin phototypes 2-4 for 755 nm Alexandrite LHR at two study sites, receiving treatment in axillae and pubic areas. Ultrafine particle concentrations were measured during LHR for two different alexandrite lasers, with and without an external smoke evacuator. Moreover, we assessed a device for LHR with a smoke evacuator integrated into the handpiece. Primary outcomes were the concentration of ultrafine particles (0.2-0.3 µm) per m³ at 1 min after initiation of treatment and maximum concentrations.

RESULTS

A total of 15 patients were recruited for routine LHR. Without a smoke evacuator, already at 1 minute after treatment onset, ultrafine particle concentrations rapidly increased. Both external and integrated smoke evacuators were highly effective with a 3.7-7-fold decrease in maximal particle count. Similarly, maximal particle concentrations remained low with both smoke evacuators. At both study sites, particle concentrations decreased slowly (8 min for 50% reduction) when treatment stopped.

CONCLUSION

LHR procedures generated an increase of ultrafine particles. Both the external and integrated smoke evacuators are highly effective in controlling ultrafine particle concentrations during LHR. Once particle concentrations are elevated and the process had been completed, clearance of ultrafine particles is rather slow.

Excess hair, hair removal methods, and barriers to care in gender minority patients: A survey study

BACKGROUND

In gender minority patients, electrolysis and laser hair removal may be necessary to reduce facial and body hair in individuals seeking a more feminine appearance and/or modified gender expression. These procedures may also be required preoperatively for some gender-affirming surgeries.

AIMS

To identify (a) the frequency of unwanted facial and body hair, (b) the use of various hair removal methods, and (c) associated barriers to care in gender minority patients.

METHODS

An online-based patient survey was distributed via social media on Facebook^® , YouTube^® , and Instagram^® in fall 2018. Respondents were at least 18 years old and self-identified as a gender minority.

RESULTS

In total, 991 responses were recorded with a completion rate of 77%. Considering excess hair, 84% of transwomen on feminizing hormone therapy (FHT: estrogen and anti-androgen therapy), 100% of transwomen not on FHT, and 100% of nonbinary individuals on FHT reported excess facial/body hair. Laser hair removal (18%) and electrolysis (17%) had similar rates of use in this cohort and were more commonly reported for nonsurgical gender-affirming purposes than preoperative preparation. Cost was the most frequently cited barrier to care.

CONCLUSION

As the majority of transwomen and nonbinary people on feminizing hormone therapy had persistent excess facial/body hair, routine use of gender-affirming hormones is not sufficient to fully eliminate unwanted hair. There remains a critical need to advocate for more comprehensive insurance coverage for laser hair removal and electrolysis in gender minority patients.

Evaluation of Topical Capislow Extract and Long Pulsed Nd-YAG Laser in the Treatment of Idiopathic Hirsutism

Introduction: Hirsutism is a condition that affects 10% of women worldwide. In many cultures, hirsutism is regarded as loss of femininity and can be psychologically traumatizing to the suffering females. The aim of the present study was to evaluate how topical capislow would affect or enhance the efficacy of laser hair removal. Methods: A randomized, monoblinded, placebo controlled split face study of combined topical capislow and long pulsed Nd-YAG laser on one side of the face versus long pulsed Nd-YAG laser alone on the opposite side of the face. Laser sessions were done at 4 weeks interval for maximum seven sessions. Topical capislow and placebo were applied once daily from the day of the first laser session to the day of the last laser session. Patients were evaluated both subjectively and objectively in each laser session and for six months after the last laser session. Results: Both treatment modalities were well tolerated and accepted with significantly better results in combined capislow and laser group versus laser alone. Conclusion: Topical capislow can represent a safe and effective synergistic method for laser with faster results but this is a temporary effect retained only to the time of its application.

Long-term outcome of a patient with paradoxical hypertrichosis after laser epilation

One underreported, rare side effect of laser hair removal is paradoxical hypertrichosis. It is largely unknown what the long-term outcomes are of patients who develop this complication. We report a 21-year-old, Fitzpatrick II, male patient, who had patchy areas of dark hair affecting various body areas. An Alexandrite 755 nm laser was used to address the desired areas at energies between 20 and 22 J/cm² at 10-12-week intervals over a course of seven treatments. After three treatments, the patient noted a significant increase in the density and length of hairs involving the back, shoulders, neck, and upper arms. The patient was followed on a biannual basis, without further epilatory intervention. After 10 years, the areas of paradoxical hair growth were sparser compared to immediate post-treatment but remained denser compared to pre-treatment. This case illustrates improvement in the condition over time without intervention. Further studies are needed to determine the etiopathogenesis of this phenomenon.

Photoepilation and Skin Photorejuvenation: An Update

The effectiveness of intense pulsed light (IPL) and laser devices is widely accepted in aesthetic dermatology for unwanted hair removal and treatment of a variety of cutaneous conditions. Overall, most comparative trials have demonstrated similar effectiveness for IPL and laser devices. Literature studies alternatively favor the IPL and laser concepts, but the incidence of severe local pain and side effects were generally lower with IPL. IPL phototherapy, already established as a sound option in photoepilation and treatment of photoaging, hyperpigmentation and other skin conditions, is also considered first choice in the phototherapy of skin vascular malformations. When treating large areas, as often required in photoepilation and many aesthetic dermatology indications, IPL technologies show advantages over laser-based devices because of their high skin coverage rate. Compared to lasers, the wide range of selectable treatment settings, though a strong advantage of IPL, may also imply some more risk of local thermal side effects, but almost only in the hands of poorly trained operators. Overall, the strongest advantages of the IPL technologies are robust technology, versatility, lower purchase price, and the negligible risk of serious adverse effects in the hands of skilled and experienced operators.

Side effects from intense pulsed light: Importance of skin pigmentation, fluence level and ultraviolet radiation-A randomized controlled trial

BACKGROUND AND OBJECTIVE

Intense pulsed light (IPL) is a mainstream treatment for hair removal. Side effects after IPL are known, but risk factors remain to be investigated. The objective of this study was to assess the contribution of skin pigmentation, fluence level, and ultraviolet radiation (UVR) on IPL-induced side effects.

METHODS

The study was a blinded, randomized intra-individual controlled trial including 16 healthy subjects with Fitzpatrick Skin Types (FST) II-V. Three test areas were each divided into four sites, randomized to a single IPL exposure of 22, 34, 46 J/cm² or triple stacking of 46 J/cm² . Areas were subsequently randomized to no UVR or single solar-simulated UVR exposure of 3 Standard Erythema Dose at 30 minutes or 24 hours after IPL. Each area had a corresponding control, resulting in 15 treatment sites. Follow-up visits were scheduled up to 4 weeks after IPL. Outcome measures were: (i) blinded clinical skin reactions; (ii) objectively measured erythema and pigmentation; (iii) pain measured by visual analog scale (VAS); (iv) histology (H&E, Fontana-Masson); and (v) mRNA-expression of p53.

RESULTS

Fifteen subjects with FST II-IV completed the protocol. IPL induced a wide range of skin reactions, including erythema (87% of subjects), purpura (27%), blisters (20%), edema (13%), crusting (13%), hyper- (60%), and hypopigmentation (20%). Darker skin pigmentation and increasing IPL fluence were determinants for IPL-induced side effects (P ≤ 0.002), while a single exposure of UVR did not exacerbate side effects (P ≥ 0.180). Clinical findings were confirmed objectively by reflectance spectrometry and qualitatively by histological changes in skin architecture, inflammatory infiltration, and pigmentation. Marker of cellular DNA damage, that is, p53, did not increase after IPL (P ≥ 0.24).

CONCLUSIONS

Skin pigmentation and IPL fluence are major determinants of side effects after IPL exposure, while a single exposure to three SED of UVR at 30 minutes or 24 hours after IPL, does not amplify such side effects. Lasers Surg. Med. 49:88-96, 2017. © 2016 Wiley Periodicals, Inc.

Laser hair removal for genital gender affirming surgery

Genital gender affirming surgery (GAS) involves reconstruction of the genitals to match a patient’s identified sex. The use of hair-bearing flaps in this procedure may result in postoperative intra-vaginal and intra-urethral hair growth and associated complications, including lower satisfaction with genital GAS. Despite the significant increase in genital GAS within the past 50 years, there is limited data regarding hair removal practices in preparation for genital GAS and notable variation in hair removal techniques among dermatologists and other practitioners. We present a literature review, recommendations from our experience, and a practical laser hair removal (LHR) approach to hair removal prior to genital GAS.

Ultraviolet radiation after exposure to a low-fluence IPL home-use device: a randomized clinical trial

The prevailing advice is to avoid sun exposure after intense pulsed light (IPL) hair removal. However, no systematic evaluation of ultraviolet radiation (UVR) after IPL hair removal exits. Therefore, we investigated the occurrence of side effects in subjects receiving solar-simulated UVR after a low-fluence IPL treatment with a home-use device. Sixteen subjects with Fitzpatrick skin types (FST) II-V were enrolled. Three constitutive buttock blocks (4.4 × 6.4 cm) were each subdivided into four sites, randomized to one IPL exposure of 0, 7, 8, or 10 J/cm2 (spectral output 530-1100 nm). Blocks were randomized to no UVR or three standard erythema doses (SEDs) UVR either 30 min or 24 h after IPL. Follow-up visits were 48 h, 1 week, and 4 weeks after IPL. Outcome measures were (i) clinical skin reactions, (ii) reflectance measurements of erythema and pigmentation, and (iii) pain. Subjects with FST II-IV experienced no skin reactions up to 4 weeks after IPL, neither erythema, edema, blisters, crusting, textual, nor pigment changes. Reflectance confirmed no change in erythema and pigmentation (p ≥ 0.090). UVR exposure induced erythema and increased pigmentation. The combination of IPL and UVR induced skin reactions not different to responses from UVR (IPL-UVR vs. UVR, p ≥ 0.164). Pain was generally low (median 1, range 0-4) and correlated positively with fluence and pigmentation (Spearman's rho ≥ 0.394, p < 0.001). One subject with FST V experienced perifollicular hyperpigmentation after IPL and slightly more intense when exposed to UVR. A single UVR exposure of three SEDs either shortly or 1 day after low-fluence IPL causes no amplification of skin responses in constitutive skin of individuals with FST II-IV.

A case of generalized bromhidrosis following whole-body depilatory laser

BACKGROUND

Laser treatment is a widespread method for hair removal. Despite its very common use, side effects remain relatively rare and transient.

OBJECTIVE

Axillary hyperhidrosis and bromhidrosis have already been reported in the literature after depilatory lasers. We report here a novel side effect of total body bromhidrosis following hair removal laser.

RESULTS

A 27-year-old man, phototype 3 underwent four sessions of total body depilatory laser, combining pulsed alexandrite and pulsed diode lasers. A few days afterwards, a generalized foul odor was noted and was resistant to regular deodorants and Aluminum chloride based antiperspirants. Possible mechanisms include the activation of dormant bacteria in the skin flora, sweat gland dysfunction, altered skin flora, sweat gland hormone receptor disturbances, and genetic factors.

CONCLUSION

Total body bromhidrosis and hyperhidrosis are potential complications of total body laser hair removal.

The role of natural and UV-induced skin pigmentation on low-fluence IPL-induced side effects: a randomized controlled trial

BACKGROUND AND OBJECTIVES

The risk of adverse skin effects following light-based hair removal is greater in pigmented skin based on the theory of selective photothermolysis. Thus sunlight-induced pigment i.e., facultative pigmentation, increases the risk of adverse skin effects, perhaps disproportionately. The aim of this study was to evaluate the influence of constitutive and facultative skin pigmentation on low-fluence intense pulsed light (IPL)-induced adverse skin effects.

STUDY DESIGN/MATERIALS AND METHODS

Twenty-one subjects with Fitzpatrick skin type II-IV were enrolled. Two buttock blocks were randomized to receive 0 or 8 solar simulated ultraviolet radiation (UVR) exposures of consecutively increasing Standard Erythema Doses (2-4 SED). Each block was subdivided into four sites, randomized to receive IPL of 0, 7, 8, or 10 J/cm(2) , once a week for 3 weeks. Biopsies were taken 16-24 hours after the first IPL exposure and subjects were seen 1 and 4 weeks after the last IPL exposure. Outcome measures were: (i) skin reactions, (ii) pain, (iii) mRNA expression of pigment-markers microphthalmia-associated transcription factor (MITF) and pro-opiomelanocortin (POMC), and (iv) clinical appearance of biopsy wounds.

RESULTS

Skin pigmentation increased after UVR (baseline median 13.8%, after UVR 28.1%, P = 0.0001) in all skin types. Subjects reported low pain intensities (median 1.5, scale 0-10) and experienced transient erythema immediately after IPL exposure. No persistent erythema, blisters, crusting, textual, or pigment changes were observed. The risk of erythema and pain intensities increased with IPL dose and skin pigmentation (P < 0.03). There was no difference in pain or skin reactions in skin with similar degree of natural and facultative pigmentation (P ≥ 0.104). Expression of cellular pigment-markers was not influenced by IPL exposure, neither in constitutive nor in facultative pigmented skin. Clinical appearance of biopsy wounds was unaffected by IPL exposure.

CONCLUSION

The prevalence and intensity of low-fluence IPL-induced adverse skin effects depended on IPL dose and skin pigmentation regardless of the origin, i.e., constitutive versus UV induced.

Guidelines on the safety of light-based home-use hair removal devices from the European Society for Laser Dermatology

In the past 5 years since their US introduction, there has been a rapid proliferation of light-based hair removal devices intended for home-use. In the last 2 years in Europe, sales already run into many tens of thousands of units with well-known multi-national companies entering the market. These guidelines provide a definition of light-based home-use technology, to inform healthcare professionals about home-use light-based technology and encourage manufacturers wishing to sell in Europe to adopt 'best practice'. The review presents the current status on standards and regulation issues and considers home-use safety issues, encompassing human, device and electrical safety, given risks to the eyes and skin from optical radiation both to the consumer and persons in the vicinity. Proposed technical measurement methodology is considered with focus on recognized critical parameters for the safe use of light-based hair removal technology including recording the technical performance and safety claims of a range of home-use hair removal devices. The literature review emphasizes potential adverse incidents and safety aspects of treating cosmetic conditions, such as unwanted hair growth. Although some regulations exist, they differ from region to region and there is a specific need for international common principles and guidelines relating to the manufacture, marketing and use of intense pulsed light and laser devices, including manufacturing standards for home-use products intended, amongst others, for cosmetic hair removal and photo-rejuvenation procedures. In these guidelines, the European Society for Laser Dermatology (ESLD) provides a professional view of what 'best practice' may imply for manufacturers and consumers alike.