Comparison of 15% 5-aminolevulinic acid and 10% 5-aminolevulinic acid photodynamic therapy for the treatment of acne vulgaris: a split-face randomized pilot study

Introduction: Acne vulgaris is a highly prevalent skin disorder, driving the ongoing search for innovative treatment modalities. While numerous studies have demonstrated the effectiveness of photodynamic therapy (PDT) in managing acne vulgaris, there remains a lack of clear guidlines regarding optimal treatment parameters. Aim: To assess the efficacy and safety of 10% concentration 5-aminolevulinic acid-(ALA) in comparison to 15% ALA PDT for treating facial acne vulgaris. Material and methods: A randomized, double-blind, split-face clinical trial was conducted on 25 patients with moderate to severe acne (Leeds grades 2-4). Patients were randomly assigned to two groups with different ALA concentrations applied on one cheek, while a placebo was applied on the other side. After a 1.5-hour incubation, illumination with 633 nm red light from a Light Emitting Diode (LED) lamp (96 J/cm(2)) was performed in three sessions with 7-10 days' intervals. Treatment effectiveness was assessed by the lesion reduction rate based on lesion counts before the study, after each session, and at 4 and 8 weeks after the last session. Results: Both 15% and 10% ALA-PDT treatments demonstrated significant reductions in inflammatory acne lesion counts compared to the placebo: 10% ALA-PDT showed a reduction of 27.36% versus 12.64% for the placebo (p = 0.04), while 15% ALA-PDT showed a reduction of 40.45% compared to 13.41% (p < 0.01). However, there was no significant difference between ALA-PDT and placebo in treating non-inflammatory lesions. Additionally, there was no difference between the effectiveness of 10% and 15% ALA in reducing any type of acne lesions. Conclusions: ALA-PDT is effective in treating acne vulgaris. However, ALA-PDT provides an advantage over red light only for inflammatory acne lesions. The study indicates that higher concentrations of ALA do not result in more significant reductions in acne lesions.