Pawel Posadzki, PhD; Josip Car, MD, PhD
Acne is a chronic, immune- and hormone-mediated, inflammatory disease with high prevalence (range, 70%-95%) especially among adolescents. Acne affects individuals’ quality of life and psychological health, and it has the potential for permanent scarring. A wide range of light therapies of different wavelengths, doses, and/or active substances are purported to safely and effectively treat acne.
This JAMA Dermatology Clinical Evidence Synopsis summarizes key findings from a Cochrane review of the light therapies for acne.
Our review examined a number of light therapies, but herein we focus on MAL-PDT (vs placebo or no treatment) because it has slightly stronger evidence for effectiveness. Please refer to the full Cochrane review for other light therapies for which there is insufficient evidence for clinical effectiveness, such as red, yellow, green, blue, blue-red, infrared, broad spectrum light, intense pulsed light, aminolevulinic acid-PDT, pulsed-dye lasers, 1450-nm lasers, or blue light–emitting diodes.
Summary of Findings
Of 71 included studies (51 comparisons), only 5 studies were homogeneous enough for pooling. Meta-analysis of 3 studies showed that 4 sessions of 80-mg/g MAL plus red light probably (the word “probably” in evidence synthesis language denotes “moderate certainty evidence” and moderate confidence in effect estimates) had little effect on investigator-assessed change in the number of inflamed lesions compared with placebo cream plus red light at 6 weeks (mean difference [MD],−2.85;95%CI,−7.51 to 1.81; 360participants; moderate certainty evidence). One additional study showed that 2 sessions of 160-mg/g MAL-PDT plus red light may improve this outcome compared with no treatment at 12 weeks (MD, −24.20 inflamed lesions; 95% CI, −36.95 to −11.45 inflamed lesions; 24 participants, low certainty evidence).Meta-analysis of the same 3 studies showed that 4 sessions of 80-mg/g MAL plus red light probably increased investigators’ global assessment of improvement compared with placebo cream plus red light at 6 weeks (risk ratio [RR], 1.74; 95% CI, 1.11-2.74; moderate-certainty evidence). One additional study showed that 4 sessions of 40-mg/g MAL plus red light probably had little effect on this outcome compared with placebo cream plus red light at 6 weeks (RR, 1.56; 95% CI, 0.47-5.20; 102 participants; moderate-certainty evidence). The magnitude of the effect was typically small, and none of these changes were clinically significant. There was 1 investigator assessed severe adverse effect in the treatment group of 4 sessions of 80-mg/gMAL plus red light compared with placebo cream plus red light at 6 weeks (risk difference, 0.00; 95% CI, −0.02 to 0.02; 360 participants; moderate-certainty evidence) (Table). The magnitude of the effect was typically small, and none of these changes were clinically significant for all the outcomes. In other words, light therapies were not effective enough to warrant changes to clinical care.
Keywords: Abridged Index Medicus ; Acne Vulgaris – therapy ; Index Medicus