Investigation of optimal aminolaevulinic acid concentration applied in topical aminolaevulinic acid-photodynamic therapy for treatment of moderate to severe acne: a pilot study in Chinese subjects

Summary Background Aminolaevulinic acid–photodynamic therapy (ALA‐PDT) is a novel and effective treatment in acne. However, little is known about the effect of different concentrations of ALA in the treatment of acne in Chinese patients with Fitzpatrick skin type III and IV. Objectives To investigate the efficacy and safety of ALA‐PDT in the treatment of moderate to severe acne in Chinese patients and to identify the suitable concentration of topical ALA. Methods One hundred and eighty patients with moderate to severe facial acne were recruited and randomly divided into four groups. Each group was treated with a different concentration (5%, 10%, 15% and 20%) of ALA to the facial lesions on the right side and placebo agent on the left side as control. Each patient was treated once every 10 days for four sessions. The numbers of inflammatory and noninflammatory acne lesions were counted at baseline and at weeks 2, 4, 12 and 24 after the last treatment. Adverse effects were recorded at each follow‐up visit. Results After 24 weeks, each side treated by ALA‐PDT showed clinical improvement compared with the control side treated by red light alone (P