Background: Low-fluence (low irradiation energy density) pulsed-dye lasers (PDLs) have been used for atrophic acne scarring, and anecdotal experience suggests that long-term improvements in inflammatory acne can be seen after one PDL treatment. Our aim was to compare the efficacy and tolerability of such PDL treatment with sham treatment in patients with facial inflammatory acne in a double-blind, randomised controlled trial.
Methods: We recruited 41 adults with mild-to-moderate facial inflammatory acne. We randomly assigned patients to PDL (n=31) or sham treatment (n=10). Treatment was given at baseline and patients were seen after 2, 4, 8, and 12 weeks. Assessors and participants were unaware of treatment allocations. Primary outcome measures were acne severity after 12 weeks and adverse events at any time. Secondary measures were change in lesion counts after 12 weeks and change in acne severity with time. Analysis was by intention-to-treat.
Findings: After 12 weeks, acne severity (measured by Leeds revised grading system) was reduced from 3.8 (SD 1.5) to 1.9 (1.5) in the PDL group and 3.6 (1.8) to 3.5 (1.9) in the sham group (p=0.007). Treatment was well tolerated. Total lesion counts fell by 53% (IQR 19 to 64) in PDL patients and 9% (-16 to 38) in controls (p=0.023), and inflammatory lesion counts reduced by 49% (30 to 75) in PDL patients and 10% (-8 to 49) in controls (p=0.024). The most rapid improvements were seen in the first 4 weeks after treatment.
Interpretation: PDL therapy improves inflammatory facial acne 12 weeks after one treatment with no serious adverse effects.