The best and worst of light therapies for acne

Dermatologists turning to the literature for guidance on the effectiveness of light therapies on acne vulgaris might come up empty-handed. The body of research looking at lasers and other light therapies for acne fails to offer robust evidence on efficacy and more, according to a systematic review published in October in the British Journal of Dermatology.

But a few notable clinical takeaways did surface.

Pooled data from three studies, reflecting a total 360 subjects with moderate-to-severe acne, showed that photodynamic therapy with red light-activated methyl aminolevulinate had a similar effect on changes in lesion counts as a placebo with red light. On this topic, the authors judged the quality of evidence as moderate, and they mentioned that current evidence doesn’t support methyl aminolevulinate photodynamic therapy as a standard moderate-to-severe acne treatment.

A standard therapy for moderate-to-severe acne used today - 20 percent aminolevulinic acid-photodynamic therapy activated by blue light - was not supported by a body of low and very low quality evidence in this review. It failed to show superior effectiveness when compared to blue light, alone.

But evidence, overall, suggests that using aminolevulinic acid doses at 15% and 10 percent, along with light modalities that aren’t blue light might be of benefit. Several studies suggested a higher aminolevulinic acid dose of 20 percent increased risk of blistering and other adverse effects.

The authors did not find studies to justify recommending blue light as monotherapy. But red light, alone, emerged as promising in several studies. The problem with the red light studies, according to the authors, was they were at high risk of bias.

More recent studies in the review suggest blue-red light might be more effective than blue light, alone, or placebo.

In small studies, green light therapy was more effective than placebo or more treatment.

Other therapies that did not show clinically significant effects on acne vulgaris in studies were yellow light, which researchers compared with placebo and no treatment; infrared light, compared to no treatment; gold microparticle suspension versus vehicle; and clindamycin/benzoyl peroxide and pulsed dye laser compared to clindamycin/benzoyl peroxide alone.

While most studies reported adverse effects, they do so inadequately, according to the authors. Blistering, which the authors defined as a severe adverse effect, was reported in studies on infrared light, intense pulsed light, 37J/ cm² methyl aminolevulinate-photodynamic therapy with occlusion and Aminolevulinic Acid–photodynamic therapy.

About the review

Researchers conducted a Cochrane review to better understand the efficacy of using laser and other light sources to treat acne vulgaris patients. They looked not only for studies that analyzed whether the devices improved acne, but also what patients thought of the treatment and how it might have impacted their quality of life.

The review of 71 studies, with a total of 4211 subjects, included papers up to September 2015. It looked at lasers and other light sources, individually, and at photodynamic therapy. Study subjects were predominately young adults with mild-to-moderate acne.

Reporting issues came to light. Variations in the way researchers conducted studies resulted in a lack of clarity in important measures, including lesion count changes. The review also yielded inadequate reporting of side effects. This lack standardization in a majority of studies occurred despite the availability of free tools to improve reporting of randomized control trials, they write.

Long-term data is lacking, according to the review.

And more than half of the studies in the review were industry-funded. In some cases, authors reported conflicts of interest, but, sometimes, industry and other ties weren’t included.

As a result, the review’s authors write, drawing firm conclusions from the exiting literature isn’t possible. It isn’t clear, according to the authors, if the light therapies studied are better than other options, including other treatments, placebos or no treatment.

Quality of life impact, assessed in only three studies, is also lacking and fails to paint a picture about whether acne patients see beneficial effects from lasers and other light source treatments.

The authors write their conclusions differ than those of previous reviews in a few areas, including the efficacy of pulsed-dye lasers, or yellow light, for acne. In a systematic review published in 2013, for example, which looked at pulsed dye laser efficacy in treating inflammatory skin diseases, the authors gave pulsed dye laser treatment a B level of recommendation, writing the light therapy can be recommended as an effective and safe treatment for localized acne vulgaris.

On the other hand, this latest review is in agreement with previous reviews regarding the general direction of evidence for green light, blue light, blue-red light and infrared light lasers, with other authors also calling for better quality comparative studies.

There is a need for more robust, standarized, larger, longer-term studies comparing the efficacy of light therapy acne treatments with other types of commonly used acne therapies, the authors write.

DISCLOSURES

A.M. Layton reported conflicts of interest with research projects from Galderma, GlaxoSmithKline, MEDA, LeoPharma, Intendis, Valeant, Dermira, Pfizer, Novartis, Wyeth and L'Oreal; and honoraria for lecturing at educational meetings or supported work conducted in an advisory capacity.

REFERENCES

J. Barbaric, R. Abbott, P. Posadzki, et al. "Systematic Review:  Light therapies for acne: abridged Cochrane systematic review including GRADE assessments," British Journal of Dermatology (BJD). Accepted manuscript online: March 24, 2017 DOI: 10.1111/bjd.15495 http://onlinelibrary.wiley.com/doi/10.1111/bjd.15495/abstract

Erceg A, de Jong EM, van de Kerkhof PC, Seyger MM. The efficacy of pulsed dye laser treatment for inflammatory skin diseases: a systematic review. J Am Acad Dermatol. 2013 Oct. doi: 10.1016/j.jaad.2013.03.029.