Comparison of blue laser and red light-emitting diode-mediated aminolevulinic acid-based photodynamic therapy for moderate and severe acne vulgaris: A prospective, split-face, nonrandomized controlled study

Background: Acne is a chronic inflammatory skin disease. Photodynamic therapy (PDT) is a highly effective and safe drug-device combination treatment, typically using red and blue light. However, direct comparisons of aminolevulinic acid (ALA)-based PDT using these two light sources are lacking. Therefore, we compared the efficacy and adverse effects of ALA-based 450 nm blue laser-mediated PDT (BL-PDT) and 630 ± 10 nm red light-emitting diode-mediated PDT (RL-PDT) in the treatment of moderate-to-severe acne vulgaris, including analyses of different lesion types. Methods: Sixteen patients with moderate-to-severe acne vulgaris were recruited. All patients underwent BL-PDT on the left side of the face and RL-PDT on the right side. Treatments were administered thrice at 2-week intervals, and follow-up continued for 2 weeks after the final treatment. The average rates of improvement in inflammatory and non-inflammatory acne lesions, IGA (Investigator's Global Assessment) scales, and IGA success rates were calculated. In addition, adverse effects during and after each treatment were recorded. Results: At the 2-week follow-up after the final treatment, the average rates of improvement in total acne, inflammatory, and non-inflammatory lesions were 48.0 %, 63.0 %, and 30.0 % in the BL-PDT group and 42.2 %, 58.1 %, and 27.5 % in the RL-PDT group, respectively. The IGA scores for the two groups decreased by 1.8 and 1.7 points, respectively, and the IGA success rate was 53.3 % in both groups. There were no significant differences between the BL-PDT and RL-PDT groups in any measure of effectiveness. However, the BL-PDT group exhibited more severe adverse effects, especially pain and hyperpigmentation. Conclusions: BL-PDT and RL-PDT have similar efficacies in moderate-to-severe acne vulgaris and are particularly effective for inflammatory acne lesions. RL-PDT benefits from milder adverse effects than those of BL-PDT.