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Methyl aminolevulinate-photodynamic therapy more effective than light therapy for acne

Methyl aminolevulinate-photodynamic therapy displayed a quicker and higher response rate than red light therapy alone in treating patients with acne vulgaris, according to study results.

Researchers in Chile studied 36 patients with mild to moderate facial acne. Eighteen patients (mean age, 22.1 years; 13 women) received methyl aminolevulinate-photodynamic therapy (MAL-PDT) with a commercial MAL cream 160 mg/g; the other 18 patients (mean age, 20.7 years; 10 women) received only red light therapy for two sessions at two weeks apart. In the MAL-PDT group, cream was applied in a 1-mm thick layer and covered with an impermeable dressing for 90 minutes. Both groups received 9 minutes of illumination with a PDT 1200 lamp (average wavelength 635 nm, light dose 37 J/cm2 and a fluence rate of approximately 70 mW/cm2. Masked evaluators assessed acne severity grade, inflammatory and noninflammatory lesions at baseline, 2, 4 and 10 weeks.

In 82.3% of the MAL-PDT group, acne improved at week 2 from grades II-IV to grades 0-I compared with 14.2% of patients in the red light group. The MAL-PDT group showed rapid clinical improvement with 100% response at 10 weeks, while the red light-treatment cohort had gradual improvement with 77% response at week 10.

While both treatments were significantly effective for improving lesions, the MAL-PDT had a greater response (P<.001). Side effects included pain, erythema and epithelial exfoliation. A skin biopsy performed on one MAL-PDT patient indicated decreased amounts of sebocytes, lipids and atrophic sebaceous glands after treatment.

“The results of our study indicate that red light MAL-PDT and red light alone are significantly effective for improving inflammatory and noninflammatory lesions,” the researchers concluded. “Nevertheless, red light MAL-PDT has a quicker onset of action and a higher response than red light alone.”