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/cm²) 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.