Recent advances in the treatment of acne using radiofrequency techniques.

Acne is a long-lasting inflammatory skin condition that impacts the sebaceous units of the hair follicles, affecting around 85-90% of the population. Due to the potential for permanent facial scarring and negative social consequences, as well as the limitations of conventional medications like drug resistance and difficulties following treatment plans, it's crucial to investigate non-pharmacological options for treating acne, among which radiofrequency(RF) shows distinct superiority. To assess the impact of RF in the management of acne vulgaris, we conducted a thorough examination of scientific literature (including clinical trials and scientific reviews) through electronic databases like MEDLINE and PubMed. Our analysis indicates that RF could be a viable substitute for acne treatment due to its notable effectiveness and minimal adverse effects.

The use of fractional radiofrequency in Asian patients to improve skin texture.

BACKGROUND AND OBJECTIVES: Fractional radiofrequency devices have been demonstrated to improve skin texture, such as smoothness, rhytides, brightness, and atrophic acne scars, by increasing dermal thickness, dermal collagen content, and dermal fibrillin content. The objective of the study is to assess the efficacy and adverse effects of this device on Asian patients of skin type III and IV with skin textural changes. MATERIALS AND METHODS: The study was designed as a prospective, open-labeled single-arm study, which was conducted with 20 Chinese patients aged 21-60 years and having irregularities in their skin texture, rhytides, and acne scars. The patients received six treatments at intervals of 4 weeks. Treatment was initiated with the maximum energy tolerated, which was then adjusted during the course of treatment if the patients felt excessive discomfort. A total of two passes were delivered in each session. Physician assessment results and standardized photographs were collected at the baseline, after all treatment visits, and at 1, 2, and 6 months after the final treatment visit. RESULTS: A total of 17 patients completed the study according to the established protocol. At the 6-month follow-up, 71% of patients were satisfied and 24% of patients were very satisfied with the received treatments, and the treatment physician reported varying degrees of improvement based on the global assessment scale in 60% of the subjects. While the anticipated side effects, such as erythema, edema, pinpoint bleeding, scab formation, and flare of acne, were noted in the patients, no serious adverse effects occurred. CONCLUSION: The use of fractional radiofrequency improves skin texture and is safe for use in Asian patients of skin type III and IV. No long-term serious adverse effects were noted.

A 595 nm pulsed dye laser as an adjuvant intervention for post-comedone extraction erythema and comedone reduction: A randomized, split-face controlled trial.

BACKGROUND: Comedone extraction provides greater satisfaction for acne treatment than conventional treatment alone; however, post-comedone extraction erythema (PCEE) remains a concern for patients. OBJECTIVES: To evaluate the efficacy of pulsed-dye laser (PDL) in PCEE and comedone reduction. METHODS: Mild-to-moderate acne patients were randomly allocated in split-face fashion. Three comedones were extracted on each facial side. On the PDL-treated side, 595-nm PDL was delivered to the entire side with an additional shot on three comedone-extracted sites. Erythema index (EI) and total acne lesion counts (TALC) were evaluated at baseline, week 2 and 4. The comprehensive acne severity scale (CASS) was assessed by three blinded independent pediatric dermatologists. Participant satisfaction surveys were completed at the end of the study. RESULTS: Thirty-five participants (age 12.9-24.2 years) showed no differences in the EI and TALC at baseline on both sides. At weeks 2 and 4, the EI on the PDL-treated side was significantly lower (p < 0.001) with a greater EI reduction (p < 0.001) when compared to the control side regardless of gender and menstruation. There was significantly lower TALC on the PDL-treated side at week 2 (p < 0.001) and week 4 (p = 0.02). No complications were noted with high participant satisfaction reported (median 8; IQR 7-9). PDL remained significantly associated with EI improvements after controlling for gender, menstruation cycle, and examination stress. CONCLUSION: PDL can be an adjunctive intervention for the treatment of PCEE and comedone reduction due to its effectiveness and high participant satisfaction.

1726 nm Lasers for the Treatment of Acne Vulgaris.

The treatment of acne vulgaris traditionally consists of a combination of topical and oral medications. The use of lasers to treat this condition has been an area of increasing research, and several types have previously been used in the treatment of acne. New 1726 nm lasers specifically target the sebaceous gland, which is known to be pivotal in acne pathophysiology. This laser wavelength demonstrates substantial potential as a safe and effective therapeutic option for moderate to severe acne without the risks of systemic therapy. This paper reviews the 1726 nm lasers for acne vulgaris.

Selective photothermolysis in acne treatment: The impact of laser power.

BACKGROUND: Selective photothermolysis (SPT) using a 1726 nm laser has emerged as a safe and effective treatment option for acne vulgaris by targeting sebaceous glands (SG). Power output plays a crucial role in determining treatment selectivity and efficacy. AIMS: This work highlights the advantages of a higher-power laser source and outlines the limitations of lower-power laser sources and the subsequent impact on treatment. METHODS: Light transport and bioheat transfer simulations were performed to demonstrate photothermal impact on the SG and the surrounding dermis when irradiated by a high- or lower-power laser source. RESULTS: The simulations showed that a single higher-power-shorter-pulse (HPSP) selectively increases SG temperature well beyond bulk temperatures, which is desirable for SPT. Selectivity decreases linearly with power for the single lower-power-longer-pulses (LPLP) exposure. A multiple-LPLP approach elevates bulk temperatures significantly more than a single-pulse strategy, compromising selectivity. CONCLUSION: The goal of SPT is to damage SG safely and effectively by creating an intense temperature rise localized to the SG while moderately increasing the dermis temperature. This goal is mostly achieved with higher-power lasers that deliver a single HPSP. Lower-power lasers, longer pulse widths, and multi-pulse strategies result in higher bulk temperatures and lower SG selectivity, making such treatment challenging to execute while adding a higher risk of discomfort and downtime.

The efficacy and safety of low- versus high-fluence fractional picosecond Nd:YAG 1064-nm laser in the treatment of acne scars: A randomized split-face comparison study.

BACKGROUND: Differences in clinical efficacy based on the fluence of fractional picosecond laser treatment for acne scars are unknown. OBJECTIVE: To compare the efficacy and safety of low-fluence versus high-fluence fractional picosecond Nd:YAG 1064-nm laser treatment in acne scar patients. METHODS: In this 12-week, investigator-blinded, randomized, split-face study, 25 patients with moderate-to-severe acne scars received three sessions of high-fluence laser treatment (1.0 J/cm2 ) on one side of their face and low-fluence (0.3 J/cm2 ) on the other side every 4 weeks. Patients were assessed using acne scar counts, the scar global assessment (SGA), and the ECCA scar grading scale every 4 weeks. The histological analysis compared the acne scars obtained before and 4 weeks after treatment. RESULTS: At their last visit, 88.00% and 92.00% of the subjects achieved >30% reduction in scar counts on the low- and high-fluence sides, respectively, without a significant difference between the two sides. On both sides, the scar counts, SGA, and ECCA score significantly improved 4 weeks after the last treatment. Although the high-fluence side showed a greater reduction in scar counts (-66.73%) than the low-fluence side (-62.13%), the two sides had no significant difference in the grading scores. The high-fluence side showed significantly more severe pain and higher side-effect scores immediately and 4 weeks after treatment. Histological analysis revealed a significantly increased collagen, elastin, and vimentin expression after treatment on the low-fluence side. CONCLUSIONS: The low-fluence setting demonstrated comparable efficacy and superior safety in treating acne scars compared with the high-fluence setting.

Efficacy of fractional CO2 laser therapy combined with hyaluronic acid dressing for treating facial atrophic acne scars: a systematic review and meta-analysis of randomized controlled trials.

The present work aimed to systematically identify the efficacy and safety of fractional carbon dioxide (CO2) laser plus hyaluronic acid (HA) dressing in dealing with facial atrophic acne scars. Randomized controlled trials (RCTs) concerning fractional CO2 laser in combination with HA dressing for treating atrophic acne scars were screened in 8 electronic databases (containing PubMed, Embase, the Cochrane Library, Web of Science, China National Knowledge Internet, Wanfang, Sinomed as well as VIP). Besides, for the purpose of evaluating the risk of bias of the enrolled RCTs, the Cochrane Collaboration tool was adopted. Statistical analysis was completed using Revman5.3 software and Stata 14.0 software. Meanwhile, the quality of evidence was assessed by the GRADE system. Finally, 6 studies involving 623 patients were enrolled. According to the findings in this study, compared with fractional CO2 laser alone, fractional CO2 laser therapy combined with HA dressing reduced the scores of ECCA (échelle d'évaluation clinique des cicatrices d'acné) grading scale (MD=-3.37,95% CI [-5.03, -1.70], P<0.0001), shortened the time of crust formation (MD=-0.42,95% CI [-0.80, -0.04], P=0.03) and the time of crust removal(MD=-1.31,95% CI [-1.67, -0.95], P<0.00001), enhanced patient satisfaction (RR=1.85, 95% CI [1.44, 2.38], P<0.00001). All the reported adverse events including hyperpigmentation, erythema, edema, mild itching, and slight burning pain were controllable. In addition, fractional CO2 laser combined with HA dressing therapy had a lower incidence of hyperpigmentation than fractional CO2 laser alone (RR=0.37, 95% CI [0.23, 0.61], P<0.0001). The level of evidence for outcomes was classified to be low to moderate. According to our findings, fractional CO2 laser combined with HA dressing is efficacious and safe option for facial atrophic acne scars. Nevertheless, more high-quality trials are required for further verification in the future.

Fractional CO2 laser versus 1064-nm long-pulsed Nd:YAG laser for inflammatory acne vulgaris treatment: a randomized clinical trial.

Acne vulgaris is challenging to treat for several individuals. Laser therapy may be a desirable alternative to traditional therapies with limited success. This study aimed to assess efficacy of fractional CO2 laser versus Nd:YAG laser for acne vulgaris therapy. Thirty cases with acne vulgaris underwent both fractional CO2 laser and Nd: YAG laser treatments in a randomized split face design at a 14-day interval for four sessions. The clinical efficacy was evaluated by counting acne lesions and utilizing the Global Acne Severity Scale (GEA Scale). GEAs decreased significantly after both fractional CO2 and Nd:YAG modalities after treatment and at a 3-month follow-up; fractional CO2 demonstrated significant more decrease in GEAs with (P = 0.006, 0.00 (respectively. Moreover, fractional CO2 showed a significantly higher satisfaction level (P = 0.004) and a better clinical improvement percentage regarding inflammatory and noninflammatory acne lesions (P = 0.007 and 0.000, respectively) after 3 months of follow-up. Apart from transient erythema, there were insignificant adverse effects concerning both treated sides. Fractional CO2 and Nd:YAG lasers are efficient physical modalities of acne treatment. However, fractional CO2 laser was more effective and more satisfying to the patients.

Laser treatment of acne scarring in skin of colour.

Acne vulgaris is a chronic inflammatory skin disorder that affects patients of all skin types. Acne scarring affects up to 95% of patients. Laser treatment is the most effective treatment for acne scarring. Adverse effects (AEs) include pain, infection, erythema, postinflammatory hyperpigmentation (PIH), hypopigmentation and scarring. Patients with darker skin types are more prone to developing PIH, arising as a result of inflammation, which can be intrinsic or extrinsic. There is concern that laser treatment may not be suitable for patients with skin of colour (SOC) due to the risks of AEs. However, the use of appropriate treatment protocols can help to mitigate these risks. Clinicians should consider the type of acne scarring and skin type of the patient when choosing the most appropriate laser. Laser treatments should be offered to patients with SOC, who should be fully informed of the risks before embarking on treatment. It is important to note that no treatment will eliminate scarring completely, but lasers can significantly improve the appearance of acne scars. Laser treatment for acne scarring can be performed safely and effectively when tailored to the patient's needs and skin type. Further studies are needed to evaluate the use of lasers for patients with SOC.

Optimal blue light irradiation conditions for the treatment of acne vulgaris in a mouse model.

BACKGROUND: Although blue light is one of the therapeutic approaches used to treat acne vulgaris (AV), there is no consensus on its effectiveness. As a result, it is not recommended in the major acne vulgaris treatment guidelines. OBJECTIVE: The goal of this study was to look into the mechanism, safety, and efficacy of blue light therapy. We achieved this by examining the pathological response, inflammation, and depth of light penetration in a mouse model of cystic AV. METHODS: The aims of the study were addressed by exposing the mice to light with a wavelength of 415 nm under four different irradiation conditions. The exposure was done for five consecutive days followed by a no irradiation period of 72 h. RESULTS: Blue light treatment was most effective when irradiation was performed at 100 mW/cm2 for 20 min for five consecutive days. Inflammatory responses emerged 72 h after the final irradiation dose was administered. These responses were not associated with apoptosis as cleaved caspase-3 staining revealed no significant increases in apoptosis in the skin under any of the tested conditions. Blue light reached the superficial layer of the acne cyst at 5% of the total irradiation power and was attenuated by half for every 50 µm of progress through the cyst. CONCLUSION: In conclusion, blue light could control severe dermatologic inflammatory responses; therefore, it can be used to irradiate AV with high inflammation levels on a daily basis until improvement is observed. In addition, porphyrin, a metabolite of Cutibacterium acnes, and reactive oxygen species generated by the surrounding skin tissue may have essential roles in AV treatment.

Utilization of light-emitting diodes for skin therapy: Systematic review and meta-analysis.

This study investigates the dermatological as well as the esthetic potential of light-emitting diodes (LEDs) by performing a systematic review and meta-analysis. From the electronic databases, 554 articles were assessed; however, only 31 studies were selected after manually screening and eliminating unnecessary studies. The potential effectiveness of LEDs for skin therapies was assessed by evaluating the standardized mean differences (SMDs) and funnel plots of this meta-analysis. It was discovered that both red and blue LED lights play an important role in the treatment of acne vulgaris with an overall statistically significant SMD of -2.42 [-2.64, -2.15] and I2  = 17% < 50%. Additionally, other LEDs (e.g., yellow LEDs and near-infrared devices) showed outstanding levels of effectiveness, not only in reducing the lesions of herpes simplex and psoriasis but also in improved skin rejuvenation with highly consistent analytical results (I2  = 0% and 33%, respectively). However, the analysis of LED-based skin wound healing and atopic dermatitis treatments exhibited heterogeneity (I2  = 85% and 90%) due to the lack of unpublished articles. In conclusion, it is suggested that LEDs are useful for dermatology and could be potential candidates for future cosmetic applications.

Selective photothermolysis with a novel 1726 nm laser beam: A safe and effective solution for acne vulgaris.

BACKGROUND: Selective photothermolysis on sebaceous glands is an effective method for treating acne vulgaris (AV); however, safety, efficacy, and discomfort hinder its utilization in clinical settings. AIMS: The primary objective is to evaluate the safety and efficacy of a novel 1726 nm laser with contact cooling to treat AV. METHODS: Seventeen patients aged 18 to 36 were enrolled and treated in this IRB-approved, single-center, open-label study. Patients received up to three facial laser sessions up to seven weeks apart. Follow-up visits happened ten days post-session and at the 4 and 12 weeks following the final session. The investigator assessed the severity of device-related adverse events (AEs). Investigator Global Assessment (IGA) and inflammatory lesion counts (ILC) were used as metrics to evaluate acne resolution and skin condition enhancement. Patients' perspectives on satisfaction and comfort using this technology were assessed using Subject Experience Questionnaires (SEQ). RESULTS: Safety assessment showed mild and transient AEs. All subjects tolerated anesthetics-free treatments well, with a mean treatment discomfort score of 4.9 ± 1.5. Compared to baseline, a statistically significant reduction in ILC (p = 0.003) of 52% to 56% is achieved four to twelve weeks following treatment. Long-term follow-ups showed progressive improvement 24 months post-treatment with a 97% reduction in ILC. SEQs revealed high subject satisfaction (71%) with psychosocial improvement three months post-treatment. CONCLUSION: The novel 1726 nm laser appears safe and effective for treating mild-to-severe acne. Acne resolution is apparent within the first month and progresses beyond the study duration.

Carbon Peeling Laser Treatment to Improve Skin Texture, Pores and Acne Lesions: A Retrospective Study.

Carbon peel laser treatment has been described for the improvement of skin texture, with pore reduction and acne lesion treatment. The technique consists of applying a carbon mask to the face for about ten minutes followed by laser irradiation with a Q-switched 1064 nm laser. This mechanism of action seems to be related to small carbon molecules binding both the corneocytes and serum within the hair follicles; the effect of the laser eliminates carbon bound to skin particles and the high temperature generated reduces sebum production by sebaceous glands and inhibits Cutibacterium acnes replication. Although this method was described 20 years ago, scientific data supporting its efficacy and safety have only recently been reported in small case series. For this reason, we performed a retrospective study including patients treated from January to May 2022 in the context of a private practice. Even if this study is limited by the low number of patients and its retrospective nature, this is the first research to show that carbon peel laser, performed with a standardized technique, is an effective and safe treatment for patients with acne lesions, showing pores and wrinkles, and is able to improve the overall skin aspect.

The effectiveness of fractional carbondioxyde laser and microneedle radiofrequency on acne scars.

Acne scars lead to physical and psychological problems for young adults therefore they should be treated effectively. Fractional carbon dioxide (FCL) and radiofrequency (FRFL) lasers have been both used for acne scars. The aim of this study was to evaluate the effectivity and satisfaction of combined FCL and FRFL treatment for acne scars and evaluate effect of these treatments especially on atrophic scar types retrospectively. A total of 41 patients with acne scars who received FCL + FRFL were included in this study. Photographs of patients before treatment and 1 month following the last treatment session were scored by the other blinded clinician, according to the ECCA acne scar scoring method. A significant decrease was noted in clinical scores after the treatment. Side effects were minimal and acceptable. When comparing atrophic scars to erythematous ones laser treatment was more effective for atrophic types. In conclusion, our findings revealed that laser treatment with FCL + FRFL for acne scars is successful, effective and comfortable. These combination is more effective in atrophic type acne scars.

A novel 1726-nm laser system for safe and effective treatment of acne vulgaris.

Selective photothermolysis of the sebaceous glands has the potential to be an effective alternative for treating acne vulgaris. However, the translation of this technique to clinical settings has been hindered by a lack of appropriate energy sources to target sebaceous glands, concerns surrounding safety, and treatment-related discomfort and downtime. In this work, we introduce the first FDA-approved system that combines a 1726-nm laser and efficient contact cooling to treat mild, moderate, and severe acne effectively while ensuring safety and minimal patient discomfort without adjunct pain mitigation techniques. Light transport and bioheat transfer simulations were performed to demonstrate the system's efficacy and selectivity. The resulting thermal damage to the skin and sebaceous glands was modeled using the Arrhenius kinetic model. Numerical simulations demonstrated that combining laser energy and optimal contact cooling could induce a significant temperature increase spatially limited to the sebaceous gland; this results in highly selective targeting and maximum damage to the sebaceous gland while preserving other skin structures. In vivo human facial skin histology results corroborated the simulation results. The studies reported here demonstrate that the presented 1726-nm laser system induces selective photothermolysis of the sebaceous gland, providing a safe and effective method for the treatment of acne vulgaris.

Lasers for the treatment of erythema, dyspigmentation, and decreased elasticity in macular acne scars: a systematic review.

Scarring is one of the most esthetically challenging and psychologically burdening aspects following inflammatory acne. While "macular" disease is the scar subtype with the least complicated outcome, its phase can be regarded as the most defining in the ultimate scar appearance. Moreover, with lasers recently gaining much popularity in the scientific community for managing several dermatologic conditions, we aimed to evaluate whether they would lead to significant benefits. For this systematic review, four databases consisting of PubMed, Scopus, Embase, and Web of Science were searched using a comprehensive string, with the data from the relevant yet eligible identified records qualitatively synthesized. After investigating the data obtained from the nine included studies, we found the utilized lasers, namely neodymium-doped yttrium aluminum garnet, fractional carbon dioxide, pulsed dye, erbium:glass, pro-yellow, and high-power optically pumped semiconductor, to be highly effective in managing the erythematous or dyspigmented appearance with the reduced elasticity also significantly improving. Moreover, the adverse events were both bearable and minimal, and transient. However, the degree of improvement each type of scar demonstrated following laser therapy varied based on the laser used. Neodymium-doped yttrium aluminum garnet, fractional carbon dioxide, and pulsed dye are the most commonly investigated lasers for managing macular acne scars, demonstrating eye-catching capabilities in managing either erythema or dyspigmentation. However, we still recommend that further comparative interventional studies be carried out, while the intended outcomes also assessed with objective measures for further clarification.

Treatment of acne scars with fractional carbon dioxide laser in Asians: a retrospective study to search for predicting factors associated with efficacy.

Ablative fractional laser treatment has been extensively used for resurfacing atrophic acne scars. However, few studies have investigated how the parameters set during laser procedures affect efficacy. In this retrospective study, we examined the relationship between efficacy and Fitzpatrick skin type, gender, age, follow-up duration, energy, and treatment sessions utilizing ablative fractional carbon dioxide (CO2) laser in Asians with Fitzpatrick skin types III-IV. We then analyzed the relationship between outcome and adverse effects including hyperpigmentation. Three blinded dermatologists used the ECCA (Echelle d'Evaluation Clinique des Cicatrices d'Acnluation Clinique des Cicospectively review 82 of 1034 patients who presented at our institution for atrophic acne scar treatment between August 2013 and August 2019. Factors associated with efficacy, including age, gender, Fitzpatrick skin type, energy, treatment sessions, follow-up duration, and pigmentation, were analyzed. 82 patients met inclusion criteria. Patients underwent one to three CO2 laser treatment sessions. Parameter settings for individual patients were consistent across treatments. Mean ECCA scores decreased from 102.70 ± 24.95 to 87.28 ± 24.48 (p ≤ 0.001). The number of treatment sessions and duration of pigmentation lasting shorter than 3 months positively correlated with better outcomes. All patients had erythema, which lasted longer than 3 months in 16 patients (19.51%). Post-inflammatory hyperpigmentation (PIH) affected 60 patients (73.17%) and lasted longer than 3 months in 26 patients (31.71%). One patient experienced hypopigmentation (1.22%), while 8 experienced acne flare-up (9.76%). Post-laser scars occurred in 2 patients (2.44%). Our data suggest that in atrophic acne scar treatment in Asians using fractional CO2 laser, 3 treatment sessions and duration of hyperpigmentation within 3 months have better outcomes regardless of energy, gender, age, Fitzpatrick skin type, follow-up duration, and disease course.

Q-Switched 1064-nm Nd: YAG laser versus fractional carbon dioxide laser for post acne scarring: A split-face comparative study.

OBJECTIVES: Many treatment modalities are available for post acne scarring. However, the response to the treatment is extremely variable among patients. AIM: The aim of this study was to compare the efficacy and safety of Q-switched Nd: YAG (1064 nm) and fractional CO2 (10,600 nm) lasers in the treatment of atrophic post acne scars. METHODS: This study included 20 patients with atrophic facial post acne scars graded according to Sharquie's score. All subjects received four sessions of laser treatment with a 4-week interval between the sessions. The study was designed as a double-blinded, comparative, split-face study applying Q-switched 1064-nm Nd:YAG laser to the right side of the face and fractional CO2  laser to the left side. RESULTS: Q-switched 1064-nm Nd: YAG laser achieved significantly higher improvement percentage when compared to fractional CO2  lasers (33.33% versus 17.37% Sharquie's score reduction, respectively). There was a significant negative correlation between the percentages of improvement and the patients' age on both sides and a significant positive correlation with the baseline Sharquie scores on both sides. CONCLUSION: Q-Switched 1064-nm Nd: YAG laser could be a promising safe option for the management of atrophic post acne scars.

The Efficacy of Pulsed Dye Laser Treatment for Acne Vulgaris: A Systemic Review and Meta-Analysis.

BACKGROUND: Previous reports have shown that pulsed dye laser (PDL) is promising for the treatment of acne; however, results provide conflicting evidence. OBJECTIVE: To determine the efficacy of PDL in treating acne vulgaris. METHODS: A systematic review and meta-analysis of studies published before March 31, 2020 was conducted. Randomized controlled trials and case series were analyzed. The meta-analysis estimated the standardized mean difference (SMD) in acne severity score changes in patients treated by PDL versus control and also the SMD of the acne severity scores and comedone counts changes before and after PDL treatment. RESULTS: Eleven studies were included in this systematic review. Six studies were included in the meta-analysis. Pulsed dye laser treatment was not found to be superior to the control group in treating acne vulgaris (SMD: -0.285; 95% confidence interval [CI], -0.886 to 0.317). However, single-arm studies revealed a significantly improved acne severity score after PDL therapy (SMD, -1.321; 95% CI, -2.057 to -0.586), especially when a multiple-session treatment and a longer pulse duration were employed. The comedone counts were significantly decreased after PDL therapy (SMD, -0.596; 95% CI, -1.137 to -0.054). CONCLUSION: When treatment consisted of 4 or more sessions or longer pulse duration, PDL could significantly decrease the acne severity score.