Background and objective: Phototherapy for acne with a combination of blue and red light-emitting diodes (LEDs) appears to have excellent potential in treating inflammatory acne. However, a standard twice-weekly protocol administered 3 days apart may not be practical for patients. This study aims to seek the efficacy of LED treatment in moderate to severe acne, comparing between once and alternating twice-weekly regimens.

Study design/materials and methods: Thirty subjects with moderate to severe acne, as defined by Burton's grading score, were recruited in the study. The subjects were randomly divided into two groups- one group received alternating blue (470 nm) and red (640 nm) light in two visits per week for 4 consecutive weeks, while the other group got blue and red light treatments consecutively on the same visit for 4 consecutive weeks. During the study period, conventional treatments were prohibited. Clinical assessments were performed by lesion counts and blinded comparative photographs before treatment and at 1, 4, and 8 weeks after the final treatment.

Results: There was no statistically significant difference between once- and alternating twice-weekly regimens. Both regimens provided marked improvement only for inflammatory lesions. The median percentage of acne reduction was significantly demonstrated for 1 week after finishing the course of treatment and was sustained until the end of the study. There were no side effects noted throughout the study period.

Conclusion: LED therapy is safe and effective for treatment of inflammatory acne. The treatment outcomes of once and alternating twice-weekly regimens were comparable, hence, once-weekly treatment could be considered as an alternative choice for patient's convenience. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.