Treatment of melasma with a low-fluence 1064 nm Q-switched Nd:YAG laser: Laser toning in Caucasian women

In Silico Evaluation of Nanosecond Laser Treatment of Pigmented Lesions Based on Skin Optical Properties Using a Model of Melanosome Disruption Threshold Fluence

OBJECTIVES

This study aimed to evaluate the efficacy and safety of nanosecond laser treatment of pigmented lesions in silico using a model of melanosome disruption threshold fluence (MDTF) based on skin optical properties.

METHODS

Particle size analysis and scanning electron microscopy were performed to determine the threshold fluence for melanosome disruption using a nanosecond laser. By inputting the obtained threshold fluence into the MDTF model and considering the variability in skin optical properties, irradiation parameters were calculated and compared with the results from clinical studies.

RESULTS

The threshold fluences for 532 and 755 nm nanosecond laser irradiation were determined to be 3.0 and 15.0 J/cm2, respectively. In silico analysis showed that the incident fluence for moderately pigmented skin should be 1.2 times that for lightly pigmented skin, whereas it should be 50% lower than that for lightly pigmented skin to achieve the same level of energy deposition. Clinically applied fluences for moderately pigmented skin are at the low end of the calculated range of values, suggesting that the clinical fluence is chosen to minimize energy deposition in normal tissues.

CONCLUSIONS

Our results showed that the MDTF model can be used to evaluate nanosecond laser treatments and provide clinical guidance on fluence settings based on laser-tissue interactions in moderately pigmented skin. The in silico method can, therefore, provide a robust and quantitative retrospective evaluation of the treatment effects that accounts for variation in irradiation parameters among patients by combining the MDTF model with the in vivo optical properties of individual skin types.

Effect of dual-optical pulses with temporal energy distribution on laser ablation performance in in vivo zebrafish model

A Q-switched laser system has been used in a single-pulse mode for skin melasma treatments because of instant heat deposition in the target. Despite the efficient ablation of the melanophores in the skin, the single, high-fluence pulse often causes undesirable damage to the surrounding tissue, leading to high recurrence rates. This study aims to investigate the feasibility of dual-optical pulses with a temporal energy distribution on the melasma treatment in in vivo zebrafish models in comparison to that of the single optical pulse. Based on the optical detection, the dual-optical pulses had a temporal energy distribution ratio of 4:1 and an interval of 61 μs between the two consecutive pulses. According to the histological analysis, the dual pulses removed melanophores and induced a few apoptotic nuclei with minimal recurrence. This study demonstrated that the feasibility of dual-optical pulses (energy ratio = 4:1) could enhance the laser ablation performance in vivo.

The Effect of Melasma on the Quality of Life in People with Darker Skin Types Living in Durban, South Africa

Melasma is a common skin disorder of acquired hyperpigmentation that appears commonly on the face. Although asymptomatic, melasma causes psychosocial and emotional distress. This study aimed to assess melasma's severity on people with darker skin types, evaluate the effects of melasma on the quality of life (QoL), and establish QoL predictors in affected individuals. This was a cross-sectional analytic study that enrolled 150 patients from three private dermatology clinics in Durban, South Africa who were diagnosed with melasma. The severity of melasma alongside QoL were measured using a melasma area and severity index (MASI) score and melasma quality of life scale (MELASQoL), respectively. The associations among factors and QoL were explored using multivariable methods and stepwise regression analysis. p-values less than 0.05 were considered significant. Enrolled patients were predominantly females (95%), of which 76% were of black African ethnicity, 9% were of Indian ethnicity, and 15% had mixed ancestry, with an average age of 47.30 years. Family history revealed that 61% had no prior melasma cases, while 39% had affected relatives, most commonly mothers (41%). The cheeks were the most common site for melasma. MASI score of Masi (β = 0.209, t = 2.628, p < 0.001), the involvement of cheeks (β = -0.268, t = -3.405, p < 0.001), level of education (β = -0.159, t = -2.029, p = 0.044), and being menopausal (β = -0.161, t = -2.027, p = 0.045) were found to be predictors of QoL. A regression model was created to forecast MELASQoL using these four predictors. This equation's significance lies in its ability to enable the remote assessment of MELASQoL based on these four variables. It offers a valuable tool for researchers and medical professionals to quantitatively and objectively evaluate the impact of melasma on an individual's quality of life.

Melasma treatment with a 1064 nm, picosecond-domain laser with a fractionated multibeam lens array

BACKGROUND AND OBJECTIVES

Picosecond-domain lasers have been fitted with fractionated optics for dermal remodeling. This study evaluates the safety and efficacy of a multiwavelength picosecond-domain laser, using a 1064 nm multibeam lens array, for improving the appearance of melasma.

STUDY DESIGN/MATERIALS AND METHODS

Twenty adults with a clinical diagnosis of melasma were enrolled and received 4 monthly 1064-nm, 450 ps laser treatments delivered with a 10 × 10 fractional array of 150 µm microbeams. Cosmetic units with melasma were treated with fluences ranging from 1.7 to 2.9 mJ/microbeam with a repetition rate of 6 Hz. Treatment effect was evaluation of digital images by dermatologists blinded as to the treatment conditions, comparing baseline and 3- and 8-month post-treatment images. Modified melasma area and severity index (mMASI) scores were determined by the study investigator based on clinical photography. Subject self-assessment of treatment effects was also recorded.

RESULTS

Blinded reviewers correctly identified the post-treatment image in 16 of the 20 image sets (80%). Ratings demonstrated statistically significant (p < 0.001) improvement on an 11-point scale at both the 3- and 8-month timepoints for a mean improvement of 3.7 point (range -8 to 10) or 37% improvement at the 3-month follow-up, and 2.7 (range -8 to 9) or 27% at the 8-month follow-up for all subjects. The average mMASI score showed highly significant reduction at both the 3- and 8-month follow-ups compared to baseline (p < 0.01). Most subjects (90%) were satisfied with the treatment outcome in melasma at both follow-ups, which is consistent with the treatment outcome and mMASI scores.

CONCLUSION

The fractionated, picosecond-domain, 1064 nm laser is safe and effective for improving melasma and should be considered as an adjunct to topical treatment regimens and sun-protection for management of melasma.

Treatment of Combined Freckles with Chloasma Using Q-Switched 1064 nm Laser

Objective

The present study observed the therapeutic effect and possible side effects of Q-switch 1064-nm laser with large-spot and low-energy technology in the treatment of patients with combined freckles and chloasma.

Methods

A Q1064-nm laser with a large-spot diameter of 6-8 mm, energy level of 2.0-3.3 J/cm², frequency of 10 Hz, and pulse width of 10 ns was employed for the treatment. Each patient underwent treatment 10-15 times, with an interval of 10-15 days each time. Facial care was administered before and after treatment; attention was paid to cleaning and moisturizing, avoiding light, and using sunscreens strictly. The therapeutic effects were observed and evaluated.

Results

Freckles basically subsided (effective rate = 100%) and chloasma faded (effective rate = 39.4%). Furthermore, whitening and delicacy improvement were observed in the surrounding normal skin area. After laser treatment, confocal laser scanning microscopy revealed a large number of melanin particles in the upper part of the granular layer. Moreover, the amount of melanin in the middle and lower parts of the basal layer and spinous layer was significantly decreased. None of the patients developed postinflammatory pigmentation.

Conclusion

In the treatment of freckles with chloasma, Q 1064-nm laser large-spot, low-energy technology not only removed freckles and faded chloasma but, most importantly, also reduced the incidence of postinflammatory pigmentation and improved patient satisfaction. This provided new methods and ideas for freckle laser treatment.

Stem cell-derived exosomes in the treatment of melasma and its percutaneous penetration

BACKGROUND AND OBJECTIVES

Melasma is a refractory skin disease due to its complex pathogenesis and difficult treatment. Studies have found that human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) could serve as a novel cell-free therapeutic strategy in regenerative and esthetic medicine. It could potentially treat melasma, but the skin barrier is a challenge. In this study, we aim to explore the safety and efficacy of hUCMSC-Exos in the treatment of melasma and the means to promote its percutaneous penetration.

MATERIALS AND METHODS

In the animal study about the effect of penetration, percutaneous penetration of PKH67-labeled hUCMSC-Exos was studied under microneedles, 1565 nm nonablative fractional laser (NAFL), and a plasma named Peninsula Blue Aurora Shumin Master (PBASM) treatments, observed by confocal laser scanning microscopy. In the clinical application study, 60 patients with melasma treated in our department were divided into four groups. NAFL combined with normal saline treatment was used for Group A. Microneedles, NAFL, and PBASM combined with hUCMSC-Exos treatments were used for Groups B, C, and D, respectively. Each patient received four treatments at 1-month intervals. Assessments were done using the degree of pain posttreatment, melasma area and severity score, improvement rate, physician global assessment score, satisfaction, and complications.

RESULTS

In the animal study about the effect of penetration, hUCMSC-Exos can penetrate the deep dermis under microneedles, NAFL, and PBASM treatments. In the clinical application study, compared with Group A, Groups B, C, and D showed significantly improved therapeutic effect and patient satisfaction (p < 0.05), and there was no significant difference among Groups B, C, and D.(p > 0.05). Patients in Group B reported higher pain levels than those in the other three groups (p < 0.05); the treatment experience of patients in Group D was better.

CONCLUSION

hUCMSC-Exos can improve the symptoms of melasma safely and effectively. Compared with microneedles, NAFL and PBASM can also achieve a good effect toward promoting penetration. These findings are worthy of exploration and clinical application.

Update on Melasma-Part II: Treatment

Melasma is a prevalent chronic relapsing pigmentary disorder that affects photoexposed areas, especially in women of childbearing age. Although there is currently no curative treatment available for melasma, this manuscript critically reviews the knowledge regarding photoprotection, topical and oral therapies, and procedures such as peelings, laser, and microneedling that represent the main strategies for control and prevention of this disease. As the pathogenesis of melasma is not entirely understood, there are prospects for the development of new therapeutic strategies that might act on the pathways that promote sustained pigmentation rather than merely decreasing melanin synthesis and removing melanin from the epidermis.

Update on Melasma-Part I: Pathogenesis

Melasma is a multifactorial dyschromia that results from exposure to external factors (such as solar radiation) and hormonal factors (such as sex hormones and pregnancy), as well as skin inflammation (such as contact dermatitis and esthetic procedures), in genetically predisposed individuals. Beyond hyperfunctional melanocytes, skin with melasma exhibits a series of structural and functional alterations in the epidermis, basement membrane, and upper dermis that interact to elicit and sustain a focal hypermelanogenic phenotype. Evolution in the knowledge of the genetic basis of melasma and the cutaneous response to solar radiation, as well as the roles of endocrine factors, antioxidant system, endothelium proliferation, fibroblast senescence, mast cell degranulation, autophagy deficits of the melanocyte, and the paracrine regulation of melanogenesis, will lead to the development of new treatments and preventive strategies. This review presents current knowledge on these aspects of the pathogenesis of melasma and discusses the effects of specific treatments and future research on these issues.

The Low-Fluence Q-Switched Nd:YAG Laser Treatment for Melasma: A Systematic Review

Melasma is a common pigmentary disorder with a complex pathogenesis, of which the treatment is challenging. Conventional treatment often leads to inconsistent results with unexpected pigmentary side effects and high recurrence rates. Recently, the low-fluence Q-switched Nd:YAG laser (LFQSNY) has been widely used for treating melasma, especially in Asia. We reviewed literatures on the LFQSNY treatment of melasma published between 2009 and May 2022 to evaluate the efficacy and adverse events, including its combination therapy. A systematic PubMed search was conducted and a total of 42 articles were included in this study. It was hard to summarize the heterogenous studies, but LFQSNY appeared to be a generally effective and safe treatment for melasma considering the results of previous conventional therapies. However, mottled hypopigmentation has been occasionally reported to develop and persist as an adverse event of LFQSNY, which may be associated with the high accumulated laser energy. When used aggressively, even LFQSNY can induce hyperpigmentation via unwanted inflammation, especially in darker skin. Although few studies have reported considerable recurrence rates three months after treatment, unfortunately, there is a lack of the long-term follow-up results of LFQSNY in melasma. To enhance the effectiveness and reduce the adverse events, LFQSNY has been used in combination with other treatment modalities in melasma, including topical bleaching agents, oral tranexamic acid, chemical peeling, or diverse energy-based devices, which generally reduced side effects with or without significant superior efficacy compared to LFQSNY alone.

Efficacy of low-fluence 1,064 nm Q-switched Nd: YAG laser for the treatment of melasma:a meta-analysis and systematic review

BACKGROUND

Melasma is considered as a type of acquired facial pigmentary disorder that is challenging to treat. Low-fluence 1,064 nm Q-switched Nd: YAG laser (LQSNY) has clinical benefits against melasma, however there are some disputes.

OBJECTIVE

To explore these contentious views, we conducted a meta-analysis and systematic review to evaluate the efficacy and safety of LQSNY monotherapy and combined therapy for the treatment of melasma.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases were searched for relevant articles from inception to July 2021. The resulting data were analyzed using the Review Manager 5.3 software.

RESULTS

Twelve eligible studies comprising 358 patients were included. No significant differences in melasma area and severity index (MASI) were observed between the LQSNY and drug groups (mean difference (MD):-0.26, 95% confidence interval (CI):-1.16-0.64, P=0.57). We found that combination therapy with LQSNY and drugs had a greater MASI improvement compared to LQSNY therapy alone (MD: 1.78, 95% CI 0.93-2.63, P<0.0001), nevertheless, no statistically significant results were found in melanin index (MI) and self-assessment. The melasma improvement was similar when using LQSNY alone and LQSNY combined with other lasers in terms of RMASI (MD 0.05, 95% CI:-0.61, 0.70, P=0.56). Compared to intense pulsed light (IPL) alone, LQSNY with IPL provided an added benefit for melasma severity (MD:3.23, 95%CI:0.65-5.81, P=0.01).

CONCLUSION

LQSNY can be applied as an alternative treatment for drug intolerance. Combination therapy with LQSNY and drugs or other lasers may have pleasantly surprising efficacy, but numerous studies are still needed to verify this.