To Örebro University

BACKGROUND: There is a need for alternative treatments for moderate to severe acne vulgaris. Preliminary experience suggests that topical methyl aminolaevulinate photodynamic therapy (MAL-PDT) may have potential.

OBJECTIVES: To investigate the efficacy and tolerability of MAL-PDT for treatment of moderate inflammatory facial acne.

PATIENTS/METHODS: Thirty patients aged 15-28 years with moderate to severe acne were included in a blinded, prospective, randomized, placebo-controlled multicentre study. Each side of each patient's face was randomly assigned to treatment with MAL (160 mg g1) or placebo cream, applied for 3 h prior to illumination. A second treatment was given 2 weeks later. On each occasion, patients assessed the intensity of pain using a 10-cm visual analogue scale. Inflammatory and noninflammatory acne lesions were counted at baseline and 4 and 10 weeks after the last PDT treatment. The investigator assessed the global severity of acne at baseline (seven patients had severe acne on at least one side of the face) and each study visit using a six-point rating scale. Data were analysed on an intention-to-treat basis, including all 30 patients.

RESULTS: There was a statistically significant greater reduction in the total inflammatory lesion count with MAL-PDT compared with placebo PDT at week 12; median reduction 54% [95% confidence interval (CI) 35-64%] vs. 20% (95% CI 8-50%), P = 0.0006. MAL-PDT was associated with more pain than placebo PDT, although intensity varied across centres and was reduced with repeated treatment. Local adverse events were consistent with this treatment modality.

CONCLUSIONS: MAL-PDT is effective in the treatment of moderate to severe inflammatory facial acne. Further studies are warranted to optimize this promising procedure.