Blue-Light Therapy for Acne Vulgaris

A Systematic Review and Meta-Analysis

Anna Mae Scott, PhD; Paulina Stehlik, PhD; Justin Clark, BA; Dexing Zhang, PhD; Zuyao Yang, PhD; Tammy Hoffmann, PhD; Chris Del Mar, MD; Paul Glasziou, PhD

Disclosures

Ann Fam Med. 2019;17(6):545-553. 

In This Article

Abstract and Introduction

Abstract

Purpose: Antibiotic use in acne treatment raises concerns about increased resistance, necessitating alternatives. We assessed the effectiveness of blue-light therapy for acne.

Methods: We analyzed randomized controlled trials comparing blue light with nonlight interventions. Studies included people of any age, sex, and acne severity, in any setting, and reported on investigator-assessed change in acne severity, patients' assessment of improvement, change in inflammatory or noninflammatory lesions, and adverse events. Where data were sufficient, mean differences were calculated.

Results: Eighteen references (14 trials) including 698 participants were included. Most of the trials were small and short (<12 weeks) and had high risk of bias. Investigator-assessed improvement was quantitatively reported in 5 trials, of which 3 reported significantly greater improvement in blue light than comparator, and 2 reported improvement. Patients' assessments of improvement were quantitatively reported by 2 trials, favoring blue light. Mean difference in the mean number of noninflammatory lesions was nonsignificant between groups at weeks 4, 8, and 10–12 and overall (mean difference [MD] = 3.47; 95% CI, -0.76 to 7.71; P = 0.11). Mean difference in the mean number of inflammatory lesions was likewise nonsignificant between groups at any of the time points and overall (MD = 0.16; 95% CI, -0.99 to 1.31; P = 0.78). Adverse events were generally mild and favored blue light or did not significantly differ between groups.

Conclusion: Methodological and reporting limitations of existing evidence limit conclusions about the effectiveness of blue light for acne. Clinicians and patients should therefore consider the balance between its benefits and adverse events, as well as costs.

Introduction

Approximately 50 million Americans have acne vulgaris;[1] it is the eighth most prevalent disease globally[2] and one of the most common reasons for clinical consultations,[3] including among primary care physicians and general practitioners (GPs). Among respondents to the James Lind Alliance's Acne Priority Setting Partnership survey, for example, 65% reported having sought help for acne from their GP or family doctor (higher than from a dermatologist, 45%; a pharmacist, 34%; or any other source).[4]

Several effective pharmacological treatments for acne exist, such as topical benzyl peroxide and topical or oral retinoids and antibiotics. With antibiotics, however, there is increasing concern about the global development of resistance from the use of topical and oral antibiotics. The incidence of resistance in Proprionibacterium acnes has been increasing: more than 50% of P acnes strains are resistant to erythromycin in Egypt, France, Greece, Italy, Spain, and the United Kingdom and to clindamycin in Egypt, Greece, Hong Kong, Italy, and Spain.[5,6] This resistance not only reduces the effectiveness of antibiotic treatment for acne but also can spread to untreated contacts and hence affect greater population antibiotic resistance patterns.

Alternatives to antibiotics for acne treatment are thus desirable. One recent option is the use of various forms of light therapy, particularly blue-light therapy. Light in the 407- to 420-nm wavelength range has been shown to have a bactericidal effect on P acnes.[7] The proposed mechanism is the excitation of bacterial porphyrins (coproporphyrin III and protoporphyrin IX) leading to the release of singlet oxygen and reactive free radicals that exert bactericidal effects.[3,8]

The US Food and Drug Administration (FDA) has approved light-emitting diode (LED) devices (blue, red, and blue/red light devices) for at-home use,[9] and the market for light therapy devices for acne is growing: the first device received FDA approval in 2009, and 35 devices are on the market now.[10] Patient interest in these devices is correspondingly increasing, with "Which physical therapies, including lasers and other light-based treatments, are safe and effective in treating acne?" being the top acne treatment uncertainty identified by patients responding to the James Lind Alliance survey, at 35% of respondents.[4] Given the increased availability over-the-counter treatments, patient interest, and decreasing price—as well as the concerns about adverse events and antibiotic resistance caused by present treatments—interest is likely to keep increasing.

Application of blue light does require considerable commitment by the user, however, with typical at-home devices being used twice a day for 30 to 60 minutes for 4 to 5 weeks. Therefore, evidence of the size and sustainability of any effect would be important to potential users. A 2016 Cochrane review of all types of light therapy for acne found 71 trials, with little evidence for most, but low certainty of evidence for green or blue lights.[11] Further trials of blue light have been published since, however. We therefore undertook a systematic review of randomized controlled trials examining the effects of blue-light therapy for acne compared with any other nonlight therapy, in people of any age, sex, and acne severity. The present systematic review will also underpin a proposed entry for blue-light therapies for acne in the Handbook of Non-Drug Interventions (HANDI), which aims to promote effective nondrug treatments for general practice or primary care.[12]

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