Abstract:

Objective To investigate the efficacy and safety of photodynamic therapy using different concentrations of aminolevulinic acid （ALA） in the treatment of moderate to severe acne. Methods One hundred and eighty patients with moderate to severe acne were randomly divided into 4 groups to apply different concentrations （5%, 10%, 15%, 20%） of ALA to acne lesions on the right side and placebo agent on the left side of faces as control. The whole face was irradiated with red light once a week for 4 sessions. The subsidence of lesions was evaluated by a dermatologist at the baseline and on week 2, 1 month, 3 month, and 6 month after the last treatment. Adverse effects were recorded at each follow-up visit. Results At the end of treatment, a stronger improvement was observed in ALA-treated lesions compared with those treated with red light alone （P < 0.05）. Six months after the last treatment, the effective rates were 79.55％, 88.37％, 95.24％, 97.73％ in lesions treated with ALA of 5%, 10%, 15% and 20% , respectively, significantly higher than those treated with placebo （11.51%, 9.82%, 13.50%, 10.07%, all P < 0.05）. With the elevation of ALA concentration, the effective rate together with incidence of adverse reactions including erythematous swelling and hyperpigmentation increased （all P < 0.05）. No scarring was noted. Conclusions The clinical effect of ALA-PDT is superior to that of red light alone in the treatment of moderate to severe acne. In view of effectiveness and safety, ALA-PDT using 10% or 15% ALA is recommended for the treatment of moderate to severe acne.

Key words: Acne, Aminolevulinic acid, Photochemotherapy, Concentration, Efficacy