Effectiveness of Photodynamic Therapy, 2% Salicylic Acid, and Their Combination for Moderate Acne.

Objective: This study aimed to investigate the effectiveness of photodynamic therapy combined with 2% salicylic acid for treating moderate acne.

Methods: This retrospective study included outpatients with moderate acne who consulted the Department of Dermatology at Suining First People's Hospital in Sichuan Province between April 2019 and December 2019. The patients were grouped into the photodynamic group, the salicylic acid group, and the combination therapy group, according to whether they received aminolevulinic acid photodynamic therapy, a 2% supramolecular salicylic acid topical masque applied once daily for 10 minutes and then washed off for four consecutive weeks, 2% salicylic acid therapy, or both treatments combined. The overall effective rate was calculated as the percentage of patients with a 60% or greater reduction in skin lesions. Adverse reactions were also collected.

Results: A total of 66 patients were included, with 22 patients in each group. The combination therapy group had an overall effective rate of 72.73%, which was higher compared to the photodynamic group at 40.91% and the salicylic acid group at 22.73% (5 cases, P < 0.003). The skin lesions decreased in the photodynamic group, salicylic acid group, and combination therapy group by 11.72±4.80%, 8.62±3.16%, and 15.12±7.61% (P=0.01) at week one; 26.26±5.52%, 24.19±5.88%, and 33.11±8.90% (P=0.01) at week two; 42.63±7.25%, 39.21±9.91%, and 47.31±9.15% (P=0.01) at week three; and 58.84±9.45%, 52.35±8.75%, and 65.97±7.20% (P=0.01) at week four. Some patients experienced mild discomfort (redness, itching, pain), but no severe adverse reactions were reported.

Conclusion: Photodynamic therapy combined with 2% salicylic acid therapy reduced the number of skin lesions in patients with moderate acne more than either treatment alone. The combination therapy may be tolerable with no severe adverse reactions.