Background: Acne patients who fail to respond to conventional treatments have been treated with isotretinoin, an effective treatment coming under strict regulation due to the risk of significant side effects. Photodynamic therapy (PDT) may be a viable alternative treatment for recalcitrant acne of various types and levels of severity.
Objective: To determine the safety and efficacy of combination PDT with topical 5-aminolevulinic acid (ALA) and activation by long-pulsed, pulsed dye laser (LP PDL, 595 nm) energy with topical therapy in patients with mild to severe acne.
Methods: A prospective, controlled pilot, proof-of-principle study of 19 consecutive patients (aged 16-47 years, Fitzpatrick skin types I-VI) with mild to severe cystic, inflammatory, or comedonal acne of the face was conducted. All patients had failed conventional therapy, including oral antibiotics, topical treatments, hormonal therapy, laser procedures (without ALA), and/or oral isotretinoin. Fifteen patients were treated with ALA PDT and 4 patients served as controls; all were continued on topical medications. Patients undergoing PDT were initially randomized to receive either blue light or laser energy. Because recrudescence occurred in 1 patient while undergoing multiple treatments with ALA and blue light, all subsequent patients were treated with ALA and laser energy. The total number of patients treated with LP PDL-mediated ALA PDT was 14. ALA was applied for a short 45-minute incubation followed by 1 minimally overlapping pass with the LP PDL (595 nm, 7.0-7.5 J/cm2 fluence, 10-ms pulse duration, 10-mm spot size, and dynamic cooling spray of 30 ms with a 30-ms delay). Patients treated with conventional therapy (oral antibiotics, oral contraceptives, and topical medications) or laser energy without ALA PDT served as control groups. Patients were followed monthly for up to 13 months.
Results: Complete clearance was achieved in 100% (14 out of 14) patients in the LP PDL PDT-treated group. A mean of 2.9 treatments (range 1-6; 2.0-3.7, 95% CI; n=14) was required to achieve complete clearance for a mean follow-up time of 6.4 months (range 1-13; 3.8-8.9 95% CI; n=14). The patient mean percent lesional clearance rate per treatment was 77% (64%-90%, 95% CI; n=14). Improvement in acne lesions became apparent within 1 to 2 weeks after the first treatment. Clearance in the LP PDL PDT group was superior to control groups. In the LP PDL-only control group (n=2), the patient mean percent lesional clearance rate per treatment was 32% without complete clearance after 3 to 4 treatments. In the oral antibiotics, oral contraceptives, and topicals control group (n=2), the clearance rate per treatment was 20%, the mean clearance rate per month was 4%, and complete clearance was not achieved after 6 to 10 months. In the LP PDL-mediated PDT group, treatments were well-tolerated with minimal erythema lasting 1 to 2 days. No cases of crusting, blistering, purpura, scarring, or dyspigmentation occurred. A reduction in the erythema in erythematous acne scars was observed.
Conclusion: For teenage to adult patients with recalcitrant comedonal, inflammatory, or cystic acne of various degrees of severity, ALA PDT with activation by LP PDL appears to be a safe and effective treatment with minimal side effects. LP PDL-mediated PDT may serve as an important alternative to isotretinoin. Cosmetically well-accepted, LP PDL PDT combined with topical therapy is the first PDT modality to achieve complete clearance with long-term follow-up as compared to controls.