According to a study published in the Journal of Cosmetic Dermatology, photodynamic therapy using higher concentrations of 5-aminolevulinic acid (ALA) gel was effective for significantly reducing inflammatory lesions in people with severe acne.

The investigators of this randomized, double-blind, split-face study sought to compare the efficacy and safety of photodynamic therapy using 5% ALA vs 10% ALA to treat patients with severe facial acne.

The study included 23 adult outpatients with severe facial acne who were randomly assigned to receive photodynamic therapy with 5% ALA or 10% ALA applied on the left or right side of the face. All patients participated in 4 photodynamic therapy sessions with a light dose of 96 J/cm² conducted at 10-day intervals. Inflammatory and noninflammatory lesion counts were evaluated at each visit and the reduction in lesion counts was compared between 5% and 10% ALA at 4 weeks and 12 weeks follow-up. The primary outcome was the effective rate of treatment calculated at the 12-week follow-up visit. Pain was assessed immediately following each treatment session using a numeric rating scale from 0 to 10; erythema and hyperpigmentation were also evaluated throughout the study, along with other side effects.

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Lesion counts decreased overall, but the decrease in inflammatory lesions was greater in the 10% ALA group vs the 5% ALA group at both the 4-week follow-up (79.2% vs 62.5%, respectively; P =.009) and the 12-week follow-up (88.5% vs 78.3%, respectively; P =.02). The decrease in noninflammatory lesion counts between groups was not statistically significant at either time period. The decrease in papules and pustules was greater in the 10% ALA group vs the 5% ALA group although the decrease in nodules and cysts was not significant between groups. The effective rate was significantly higher in the 10% ALA group compared with the 5% ALA group (95.7% vs 69.6%; P =.02). All participants reported mild to moderate pain following treatment, but differences in pain scores did not reach statistical significance between the 2 groups except in the first treatment session: 4 for the 5% ALA group vs 5 for the 10% ALA group; P =.01.

Photodynamic therapy using 10% ALA gel was more effective for severe acne than using 5% ALA gel. While both concentrations saw a significant reduction in inflammatory lesion counts, they were less effective for noninflammatory lesions. This may be because nodules and severe cysts are deeper than the red light penetrates; further studies of the effects of photodynamic therapy for noninflammatory lesions are warranted.

This study was sponsored by the National Science Foundation. For a complete list of disclosures, please see the full text of the study online.

Reference

Zhang J, Zhang X, He Y, et al. Photodynamic therapy for severe facial acne vulgaris with 5% 5-aminolevulinic acid vs 10% 5-aminolevulinic acid: A split-face randomized controlled study [published online June 12, 2019]. J Cosmet Dermatol. doi:10.1111/jocd.13038

This article originally appeared on Dermatology Advisor