Light therapies for acne: abridged Cochrane systematic review including GRADE assessments.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 28338214 · doi:10.1111/bjd.15495
What was done
A Cochrane systematic review and meta-analysis evaluating randomized controlled trials of light-based interventions for acne vulgaris searched through September 2015. Quality of evidence was assessed using GRADE. The review included 71 RCTs totaling 4,211 participants (median sample size 31).
What was found
A single trial (n = 266, low quality of evidence) showed little or no difference in participant-assessed improvement between 20% aminolaevulinic acid (ALA) photodynamic therapy (PDT) activated by blue light versus vehicle plus blue light. A dose-comparison study (n = 180) found 20% ALA-PDT with red light was no more effective than 15% ALA-PDT, though better than 10% and 5%. Pooled data from three trials (n = 360, moderate quality of evidence) showed methyl aminolaevulinate PDT with red light had a similar effect on lesion counts compared to placebo cream plus red light. Studies evaluating yellow light, infrared light, gold microparticles, and pulsed dye laser combined with clindamycin/benzoyl peroxide showed no clinically significant effects. Blistering was reported only in studies on intense pulsed light, infrared light, and PDT (very low quality of evidence).
Why it matters
This review indicates that current light-based acne therapies lack robust evidence of clinically meaningful efficacy over placebo or vehicle, challenging their widespread clinical and commercial use.
Limits
The majority of included RCTs had small sample sizes (median n = 31), lacked standardization in outcome measures, and rarely compared light therapies to standard first-line acne treatments. Adverse effects were inadequately reported across studies.