Adverse Effects of ALA-PDT for the Treatment of Moderate to Severe Acne Vulgaris: a Prospective Study

Inclusion Criteria: * (1) Patients diagnosed with moderate to severe acne and graded grade III-IV according to Investigator's Global Assessment (IGA) ; * (2) Patients unsuitable for drug treatment owing to various reasons and who voluntarily participated and signed informed consent following information about other alternatives; * (3) Patients who read the instructions and were willing to follow the program requirements. Exclusion Criteria: * (1) Patients who had a history of photosensitive diseases; * (2) Patients who had Modified-PDT; * (3) Patients who had oral isotretinoin in the past 3 months, used oral contraceptives or antibiotics and underwent local or facial surgery in the past 4 weeks; * (4) Female patients who were pregnant or lactating.