Lasers and light therapies represent important treatment options for active acne. Light-based therapies tend to involve specific porphyrins that selectively absorb various wavelengths of light, subsequently causing bacterial or sebaceous gland destruction. Through selective photothermolysis, and the absorption of specific wavelengths of optical radiation by target chromophores, lasers cause similar tissue destruction and thereby can produce a positive and targeted therapeutic effect. This article discusses the clinical results of various light and lasers therapies in acne, as well as proper patient selection, preparation, and procedural technique employed with the newly Food and Drug Administration-approved 1726 nm lasers for the treatment of active acne.
Key points
- •
Light and laser therapies for acne represent viable independent and adjunctive treatment options, for those in whom topical and systemic therapies have been inadequate or are otherwise intolerable or contraindicated.
- •
There are several forms of light therapy and lasers that have shown effectiveness in treating active acne through targeting Cutibacterium acnes , the sebaceous glands, or both.
- •
To maximize safety and efficacy, knowledge of appropriate laser science and parameters, in addition to careful patient evaluation and selection, is essential.
Introduction: innovative modalities for the treatment of active acne
Acne vulgaris is the most common skin condition in the United States, affecting 85% of individuals aged 12 to 24 and approximately 50% of adults [ , ]. In addition to the physical manifestations, it is a condition that carries with it significant psychosocial morbidity [ , ]. The pathogenesis is multifactorial, involving increased sebum production, proliferation of Cutibacterium acnes , inflammation, and hypercornification of the pilosebaceous unit [ ].
Standard treatments for acne include topical and systemic medications, employed in an escalating manner tailored to the level of disease activity. These may include topical retinoids, benzoyl peroxide, topical antimicrobials, in addition to systemic antimicrobials, hormonal therapy, and retinoids. Patients with moderate-to-severe acne that persists despite standard therapy and/or those who may have contraindications or intolerances to systemics, such as isotretinoin, light-based therapies, photodynamic therapy (PDT), and lasers, have been used [ , ].
Light and laser therapies may be divided based on their ability to target C acnes , the sebaceous gland, or both [ ]. Light therapies, such as red light and blue light, or the combination of the two, tend to involve specific porphyrins that selectively absorb various wavelengths of light, subsequently causing bacterial destruction. In addition to C acnes , destruction of the sebaceous glands occurs through this same principle during PDT. The efficacy of lasers, however, is based on the theory of selective photothermolysis, whereby brief pulses of optical radiation are selectively absorbed by a target chromophore with preferential absorption of a specific wavelength [ ]. This causes selective tissue injury of the target chromophore, while sparing surrounding structures [ ].
Several lasers have been used with variable success in the treatment of active acne, including fractionated carbon dioxide (CO 2 ), potassium titanyl phosphate (KTP), infrared, pulsed dye laser (PDL), neodymium-doped yttrium aluminum garnet (Nd:YAG), diode, Erbium glass, and Alexandrite lasers [ ]. The pain associated with some of these treatments and variable effectiveness is a barrier for many of these devices. This occurs due to their lack of selectivity and the absorption of light by water [ ]. Through study of the absorption spectrum of sebum, it was determined that 1726 nm exhibited 1.2 times the optical absorption in sebaceous glands as compared to water [ ]. Light absorbed at this wavelength selectively destroyed sebaceous glands alone, while sparing the surrounding epidermis [ , ]. More recently, 1726 nanometer (nm) lasers have been approved by the US Food and Drug Administration (FDA) for the treatment of moderate-to-severe acne.
Herein, the authors outline the procedural techniques and data for these newly approved 1726 nm lasers. They also provide a brief overview of other light and laser therapies for acne.
Procedural technique
Preoperative Planning
Prior to any procedure, it is important for the clinician to engage in a detailed discussion of the risks, benefits, side effects, and possible outcomes for the procedure. Traditionally, lasers and light therapies have been considered for patients with moderate-to-severe acne after topical and oral medication failure. It is especially important in these patients to set expectations, as many patients do see improvement, but there are still some who do not [ ]. In addition, multiple treatments are almost always required, necessitating consideration from a logistical as well as financial perspective. After thorough discussion, the patient should sign an informed consent documenting that this pretreatment discussion occurred, and he/she consents to proceed. A series of standardized pretreatment and posttreatment photographs should be taken for assessment, ideally including frontal, 45° and 90° angles at baseline, pretreatment, and follow-up using consistent camera settings.
The choice of device depends on both availability to the practitioner and patient characteristics. Factors to consider when selecting a device include the patient’s Fitzpatrick skin type (FST), the area affected by active acne, and the presence or absence of acne scarring. For example, for a patient with a lighter skin type and involvement of the back, light-based therapies that can target a larger surface area more efficiently might be selected. With regard to 1726 nm lasers, the 2 devices that are currently FDA-approved are the AviClear Laser System (Cutera, Inc.) and the Accure Laser System (Accure Acne Inc.) [ ]. To date, there are no studies that directly compare the AviClear and Accure lasers. The AviClear device is a 1726 nm diode laser that uses a 3 mm spot size and contact cooling [ ]. The Accure device is a 1726 nm fiber laser with forced air cooling that employs an infrared camera for continuous epidermal temperature monitoring, in order to allow for treatment to a peak epidermal temperature (40–46°C) as an objective clinical endpoint [ ]. Both devices are FDA approved to treat acne in all skin types. The Accure device notably has 2 modes that differ in that one utilizes injectable anesthesia (the “Standard Mode”), while the other (the “Boost Mode”) utilizes topical anesthesia and a proprietary pulsing method [ ].
Preparation and Patient Positioning
The patient should lie in a comfortable position for the treatment, ideally slightly supine so that the clinician may readily access all areas of the face. The area should be cleansed with an antiseptic agent (ie, alcohol or chlorhexidine). For the 1726 nm lasers, degreasing with acetone should also be performed [ , ]. In the experience of the authors, a brief period (3–5 minutes) of water-moistened gauze is applied to the face in order to cool the area prior to lasing. The area should be dried prior to beginning the administration of laser pulses. All standard laser safety precautions should be in place (including eye shields for the patient, goggles for the clinicians, and closed-door examination room with signage indicating lasing in process).
In terms of selection of laser parameters, the studies that have been performed with the AviClear laser employ a fixed 3.1 mm spot size, with fluences ranging from 10 to 60 J/cm 2 and a pulse duration ranging from 10 to 60 ms [ , ]. In one study including patients FST II-VI, an average fluence of 20.5 J/cm 2 and 22.8 J/cm 2 for single and double pulse, respectively, was used, with a maximum pulse duration of 50 ms. [ ].
Procedural Approach
Once laser parameters are chosen, the patient is in the appropriate position, and all safety precautions are in place, laser pulses should be administered using the appropriate settings. Unlike other lasers, there is no visible clinical endpoint with the 1726 nm lasers. AviClear treats to a target fluence and Accure treats to a target epidermal temperature, both correlating to sebaceous gland destruction [ ]. Laser pulses are administered with the tip in full contact with the skin for the duration of the pulse, as well as the precooling and postcooling. Pulses are administered by treating one area and moving on immediately to the next adjacent area until the whole face is treated, without any double pulses. A single pass over the entire face represents one treatment. The duration of each treatment is approximately 30 minutes [ ].
Immediate Post-Procedural Care
There are no necessary interventions immediately post-procedurally. Cold compresses or gel packs may be applied for comfort. Avoidance of heat sources (such as hot tubs or saunas) for 1 to 2 days after treatment is recommended, as well as limiting exercise on the day of treatment to avoid generating heat in the skin. Skin irritants like retinols, benzoyl peroxide, and salicylic acids should be avoided for approximately 1 week before and after treatment. Gentle skin care should be emphasized, with use of a gentle skin cleanser and moisturizer 1 to 2 times daily for approximately 3 to 5 days after treatment. Of paramount importance is sun protection. Sunscreen, ideally a mineral-based sunscreen with SPF 30 or higher, may be applied immediately after treatment and should be applied daily, in addition to avoidance of direct sun exposure. This is especially important in the week or 2 after treatment given the vulnerability of the skin after laser treatments.
Clinical results in the literature
This section details the variety of laser and light-based devices used for management of acne and is supported by a comprehensive literature review. It should be noted that while there is sufficient literature supporting use of each of the devices discussed, large-scale comparative and consensus data are limited given variation in study protocols, treatment regimens, and lack of standardized outcome measures for acne improvement [ , ].
Lights
Photodynamic therapy
PDT is the oldest light-based acne treatment and as such has the greatest body of supportive evidence, especially for patients who are nonresponders or have a contraindication to isotretinoin [ ]. PDT involves application of a photosensitizer (such as topical aminolevulinic acid [ALA] or methyl aminolevulnate [MAL]) that is then photoactivated, resulting in singlet oxygen and free radical damage that is toxic to C acnes and sebaceous glands [ , ]. Hongcharu and colleagues demonstrated the effectiveness of topical ALA plus red light PDT in 22 subjects who received treatment on the back at 4 sites, including ALA plus red light, ALA alone, light alone, and untreated control [ ]. They demonstrated both histologic changes in pilosebaceous units as well as decreased bacterial porphyrin fluorescence, sebum production, and acne in association with ALA PDT. These results, however, were achieved with significant side effects. Edema, erythema, and pain were common. Crusting and hyperpigmentation occurred, and in individuals who received multiple PDT treatments, over half had long-lasting hyperpigmentation at 20 weeks after treatment [ ].
While various laser and light sources can be used as photosensitizers, a recent systematic review suggested that visible red light and intense pulsed light (IPL) treatments following a 1 hour incubation time are most efficacious [ ]. A pilot study assessed utility of PDL-based PDT, using a 7.0 to 7.5 J/cm 2 fluence, 10 ms pulse duration, and 10 mm spot size. All 14 patients in the PDL-PDT treatment group cleared completely over a mean of 3 treatment sessions, compared to a mean of 32% lesion clearance in the PDL-only group and 20% lesion clearance in the standard of care group (topical therapies, oral antibiotics, and oral contraceptives) [ ]. The most frequent adverse event and treatment limitation of PDT were patient discomfort. While MAL has been reported to be less painful compared to ALA, a recent study showed no significant difference in reduction of acne lesions for MAL-sensitized PDT versus red-light-only PDT [ ].
PDT, and in particular ALA PDT, is an effective treatment of active acne; however, the side effect profile makes it a challenging modality for patients to tolerate throughout and immediately following the treatment. In addition, there are significant long-term side effects, including post-inflammatory hyperpigmentation, that require careful consideration prior to use in patients already prone to this adverse effect. Controlled trials are essential to prove efficacy with more gentle approaches affording this treatment the ability to be more widely applicable.
Red and blue light
LED red and blue light therapy have been FDA-approved for acne treatment since 2009 and work by destroying C acnes and activating cytokine release for an anti-inflammatory effect [ ]. A recent review article comprising 38 studies found that overall 92% of patients experienced at least partial improvement in active acne lesions with visible light, with a minimal adverse event profile including mild skin irritation and erythema [ ]. A randomized trial of 28 patients comparing the efficacy of red light versus blue light for mild-to-moderate acne found no significant difference in reduction of acne lesions between the 2 treatment groups, though the red light group had fewer adverse events (notably the red light group had no instances of hyperpigmentation) [ ]. While twice-weekly regimens are standard for visible light therapy, a recent comparative study showed both once and twice weekly treatment protocols was equally effective at reducing inflammatory lesions [ ]. Controlled trials, however, are lacking and the demonstrated utility of these treatments would benefit from comparison of red and/or blue light therapy to no-treatment controls to provide further insight.
Intense pulsed light
IPL devices emit polychromatic light, and the different wavelengths target various aspects of acne pathogenesis—namely destruction of sebaceous glands and reduction of C acnes colonization—ultimately leading to reduction of inflammatory acne lesions. Zdrada and colleagues assessed various skin properties in 27 patients following 4 weekly IPL treatments and found that sebum production decreased through IPL, while skin hydration and pigmentation remained unaffected [ ]. A recent meta-analysis, though limited by variation in study protocol and patient selection, showed that IPL treatments were non-superior to PDL and Nd:YAG treatments. In addition, IPL had lower efficiency among darker FSTs with higher risk of adverse events [ ]. Like other laser and light treatments, IPL can also be used as an adjunct to topical or oral therapies. A trial by Qu and colleagues compared use of minocycline along versus minocycline with a series of 3 IPL treatments. Results showed significantly improved inflammatory lesion count and decreased erythema in the combination treatment group [ ]. Overall, while IPL is well tolerated and efficacious, providers should exercise caution in patients with darker skin tones.
Lasers
Pulsed dye laser
PDLs exert a multimodal therapeutic effect on acne lesions. The 595 nm infrared wavelength targets the vascular component of inflammatory lesions and may also exhibit an anti-inflammatory effect by activation of cytokines [ ]. A prospective study of 41 adults with mild-to-moderate inflammatory acne assessed utility of low fluence PDL treatments (1.5–3 J/cm 2 , 3 ms pulse duration, 5 mm spot size). Subjects were randomized to 4 sessions of PDL versus sham treatment. Results showed significantly greater reduction in active acne lesions in the treatment group, with greatest improvement after the first treatment [ ]. Furthermore, PDL has effectiveness in adult female acne, whereby lesion count reduced anywhere from 49% to 92%, with an added benefit of improvement in erythematous acne scars [ ]. A randomized study of 46 acne patients compared low-dose isotretinoin (0.25 mg/kg/day) versus standard-dose isotretinoin (0.5 mg/kg/day) plus 5 sessions of PDL (4.5–5.5 J/cm 2 , 3 ms pulse duration, 10 mm spot size). Results showed significantly greater improvement in acne lesions in the PDL group versus standard of care, with fewer rebound flares and adverse effects [ ]. Compared to IPL, PDL may also exert a more lasting effect on acne lesions. A split-face study by Choi and colleagues treated 20 patients at 2 week intervals for a total of 4 sessions (8–10 J/cm 2 fluence, 40 ms pulse duration, 10 mm spot size for PDL; 530–750 nm, 7.5–8.3 J/cm 2 , 2.5 ms pulse duration, 2 passes for IPL). While both devices lead to initial improvement, the IPL-treated side showed significant rebound, while the PDL-treated side had lasting improvement in acne, with an average lesion count of 14% of baseline at the conclusion of the study [ ]. Overall, through likely a multifactorial mechanism, PDL may be an effective modality for active acne, with little down time. Further studies are needed to determine how PDL compares to other treatments, as well as the parameters for this to be safely employed in darker skinned individuals.
Potassium titanyl phosphate
Similar to PDL, KTP lasers also target vasculature, sebaceous glands, and reduce C acnes counts [ ]. Baugh and Kucaba published a randomized split-faced study comparing KTP treatments (4 twice-weekly treatments; 12 J/cm 2 fluence, 30–40 ms pulse width, 50% overlap) to contact cooling only. While there was a statistically significant improvement in Michaelsson acne severity scores for the treated side at 1 week posttreatment, this effect was not sustainable at 4 weeks after the final treatment (patient satisfaction with treatment, however, remained high at this interval) [ ]. A follow-up trial by Yilmaz and colleagues noted no significant difference in improvement of Michaelsson acne severity scores in once-weekly compared to twice-weekly regimens (5–12 J/cm 2 , 20–40 ms pulse duration, 4 mm spot size) [ ]. Taken together, this suggests that KTP lasers, in addition to IPL and PDL, are highly effective for erythema that may occur following acne. However, for KTP, the data for active acne treatment are limited.
Neodymium-doped yttrium aluminum garnet
While 1064 nm Nd:YAG lasers traditionally have been used for acne scar treatment, several studies support their role in treating active acne lesions. Gold and colleagues treated 100 patients with 650 ms Nd:YAG laser (28–64 J/cm 2 fluence, 2–3 mm spot size, pulse stacking with 5–15 pulses per lesion). Immediate improvement was noted in inflammatory lesions, and patients reported high satisfaction and found pain levels tolerable [ ]. Bakus and colleagues treated 20 patients with moderate-to-severe inflammatory acne with 8 treatments of long-pulse Nd:YAG laser followed immediately by treatment with Q-switched Nd:YAG laser. At a minimum of 12 month follow-up, patients showed an 81% reduction in acne lesions, with 60% of patients having 90% or greater reduction, with no side effects other than transient erythema [ ]. A recent randomized study compared use of long-pulse 1064 nm Nd:YAG with IPL treatment of active acne. Thirty patients were randomized into 2 groups and received 3 treatment spaced 2 weeks apart (settings of 40–50 J/cm 2 fluence, 40 ms pulse duration, 7 mm spot size for Nd:YAG, 7 J/cm 2 fluence, and 3 ms pulse width for IPL). Results showed significant improvement of overall lesions in the Nd:YAG group but not in the IPL-treated group. Furthermore, patients in the Nd:YAG group had more improvement in non-inflammatory lesions compared to inflammatory ( P =.099), along with fewer rebound flares compared to the IPL group [ ]. Another recent trial compared efficacy of Nd:YAG with PDL for inflammatory acne in a split-face design. Thirty-four patients received 3 treatments at 2 week intervals (8.5 J/cm 2 fluence, 10 ms pulse duration, 7 mm spot size for PDL, 30 J/cm 2 fluence, 5 ms pulse duration, and 7 mm spot size for Nd:YAG). Both sides were treated with a single pass and 10% overlap. Results showed no significant difference in reduction of acne lesions between the 2 treated sides; however, patients preferred Nd:YAG treatment due to fewer adverse events including erythema and swelling [ ]. Case reports and smaller studies suggest that Nd:YAG lasers can successfully treat active acne with minimal side effects; however, controlled studies examining this modality are lacking.
A 650 microsecond pulsed Nd:YAG (Aerolase) has been shown to be effective for treating active acne. In a recent study, 23 patients (FST I-VI) with mild-to-severe acne received 5 treatments, 2 weeks apart and were followed 30 days and 90 days after the last treatment. The median percent reduction in lesion count was 48.15% after one treatment and 83.72% after treatment 3, and remained at 86.67% at 90 days. These treatments were well tolerated, and adverse events were not observed. Larger clinical trials with longer follow-ups are needed to evaluate the long-term efficacy of the device for acne.
Ablative lasers
While ablative resurfacing lasers are more commonly used in the treatment of acne scars than active acne lesions, the literature does support the use of fractional ablative lasers to target and destroy sebaceous glands, ultimately improving acne. A recent randomized split-face study compared use of fractional CO 2 (0.74 J/cm 2 , 11.9% density) versus Nd:YAG laser (30–35 J/cm 2 , 20 ms pulse frequency, 10 mm spot size) for inflammatory acne, with 4 treatment sessions spaced every 2 weeks. Results showed significantly greater improvement in Global Acne Severity scale for the lesions treated with CO 2 laser compared to Nd:YAG, with greater reported patient satisfaction [ ]. A case series of 3 patients with treatment-resistant acne showed improvement with fractional Erbium:YAG laser resurfacing. Patients were treated every 3 months with the following settings: 3.5 mJ/cm 2 , 1.5 ms pulse duration, and 5 Hz. Results showed significant improvement in Investigator Global Assessment (IGA) score in all patients, with all 3 scoring IGA 0 to 1 (clear to almost clear) at 3 month follow-up [ ]. Although ablative modalities may be effective in achieving reduction in inflammatory lesion count, this treatment is aggressive and is of limited clinical practicality, especially with other less invasive and less risky treatment options available.
1726 nm lasers
Goldberg and colleagues studied the AviClear device in 17 patients and performed 3 treatments, spaced up to 7 weeks apart. Patients experienced a statistically significant reduction in inflammatory lesion count of 52% to 56% 4 to 12 weeks following treatment. At 24 months posttreatment, patients had a 97% reduction in inflammatory lesion count [ ]. This was achieved without significant pain (mean of 4.9 out of 10 in discomfort score), with no use of topical anesthetic. Alexiades and colleagues treated a larger patient population of 104 individuals, FST II-VI, with 3 AviClear laser treatments, spaced approximately 1 month apart [ ]. A greater than 50% reduction in active inflammatory lesions was seen in 32.6% of patients at 4 weeks, 79.8% of patients at 12 weeks, and 87.3% at 26 weeks. In comparison to baseline, with no subjects clear or almost clear, 36% and 41.8% were clear or almost clear at 12 week and 26 week follow-up, respectively. Patients tolerated the procedure with minimal discomfort and no topical anesthetic and there were no serious adverse events [ ].
There are several institutional review board-approved clinical trials of the Accure laser. Preliminary and unpublished data demonstrated an 80% reduction in acne lesions among 12 patients noted 12 weeks after the fourth monthly treatment [ ]. In 30 patients treated with the Standard Mode, all participants experienced a 50% reduction in acne lesions at 4, 8, 12, and 24 weeks after 4 monthly treatments, and a 90% decrease at 12 months. Side effects were similar to the AviClear laser, including erythema, edema, brief acne flares, and rarely dryness or crusting [ ].
The newly approved 1726 nm lasers have demonstrated effectiveness in 2 controlled trials for the treatment of active acne. Further clinical experience and larger controlled trials will be beneficial to underscore the clinical utility of these devices.
Potential complications/risks
When deciding which laser or light-based treatment to use, the practitioner must not only consider how to achieve the desired effects, but also be aware of potential side effects associated with general laser use, such as erythema, blistering, and burns. Patient tolerability is also a factor to consider, along with skin type and treatment area.
With both laser and light-based therapies, erythema has been cited as a commonly observed side effect. Light-based therapies, such as PDT, may also be associated with pain. In addition to these side effects, various lasers including CO 2 , PDL, and Nd:YAG lasers have been shown to cause transient post-inflammatory hyperpigmentation, while infrared lasers and PDL may cause edema [ ]. These side effects can be mitigated by tailoring appropriate energy setting and treatment procedures to achieve the desired outcome at minimal risk.
With regard to 1726 nm lasers, 2 studies including 17 and 104 participants, respectively, found mild erythema and edema to occur in nearly all patients [ , ]. Both typically resolved within hours to 3 days after the treatment [ , ]. In the smaller study, a minority of patients (29%, n = 5) experienced blistering in small areas of the treatment field, subsequently followed by scabbing, hyperpigmentation, and scarring. There was significant improvement by 3 months after the occurrence of all of these adverse effects, without intervention [ ]. Among 104 patients who underwent treatment with a 1726 nm laser for acne, there was no incidence of vesiculation, blistering, scarring, or hyperpigmentation [ ]. An acneiform flare-up occurred in 44% of patients; however, this was temporary, lasting 2 to 3 days prior to clearing [ ].
Summary
Lasers and light therapies can be highly effective in the treatment of active acne. Either as a monotherapy or in conjunction with various topicals and/or systemics, the data that are available highlight that these treatment modalities hold promise. Although the studies available have various limitations, including relatively small study sizes and a relative lack of directly comparative data between modalities, there is evidence to support a variety of light and laser therapies, many of which, such as PDT or PDL, have been utilized for other dermatologic indications for many years. It is important to carefully consider the patient’s level of disease severity and skin type when selecting a device for treatment. While future studies may further elucidate long-term efficacy and side effect profile, the newly FDA-approved 1726 nm lasers show promising results for the effective treatment of acne across all skin types.
Clinics care points
- •
For patients with acne in whom compliance with topical medications poses an issue, or who cannot tolerate/prefer to avoid systemic medications, laser and light therapies should be considered.
- •
Light therapies, such as red and blue light therapy, tend to target C acnes and can be effective in reducing inflammatory lesion count. PDT causes damage to C acnes, as well as sebaceous glands, and has proven effectiveness in improving acne. Side effects, however, are common, including pain, erythema, and edema, and long-term side effects, such as hyperpigmentation. IPL has also proven to be efficacious; however, clinicians should exercise caution regarding this modality in darker skin types.
- •
The newly FDA-approved 1726 nm lasers selectively target and destroy sebaceous glands and appear to be effective for the treatment of mild-to-severe inflammatory acne. They demonstrated a significant reduction in inflammatory lesion count in a manner that was generally very well tolerated by patients of all FSTs. Among lasers for active acne, these devices, in the authors’ experience, may have the highest utility. Our clinical understanding will benefit from future larger studies and broader clinical experience.
- •
Several studies have demonstrated the ability of various lasers, namely PDL, KTP, fractionally ablative lasers, and Nd:YAG lasers to improve acne with durable results. Further studies including comparison to commonly used medical therapies for acne, as well as larger sample sizes, are needed.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
