Photodynamic therapy, or PDT, entails the use of light-sensitizing compounds, or photosensitizers, to capture and transmit light’s energy for therapeutic purposes. This approach has emerged as an effective off-label treatment for acne, the most common skin condition treated by physicians worldwide. PDT can kill the main infectious agent (Propionibacterium acnes, or P. acnes) even in the presence of antibiotic resistance.
In the typical way that PDT is used for acne, the photosensitizer is applied as a gel or cream, and the acne is exposed to either blue or red light, with the light treatment delivered up to several hours after administration of the sensitizing agent. In some cases, the use of intense pulsed light may also be effective for the treatment of acne. Though PDT with aminolevulinic acid (ALA-PDT) is considered to be an effective therapy for acne, relatively strong side effects have limited its wider acceptance and usage. Researchers at Nippon Medical School in Japan, and at the University of Pittsburgh (USA) sought to assess the safety and efficacy of ALA-PDT in 11 Japanese patients with advanced acne.
The study used a treatment protocol for using 5% ALA that would be applied and left on the skin for two hours, followed by illumination with a broadband light source. Although 10 out of 11 patients experienced side effects, such as erythema (temporary reddening of the skin), these effects were fairly minimal and disappeared within a few days of treatment. The authors concluded that the protocol was effective for acne in Japanese and did not cause severe side effects in any of the patients, as reported in the 1 July 2014 issue of Laser Therapy.
Chlorophyll-Based PDT for Acne
Various chlorophyll compounds have been tested as photosensitizers for acne treatment, and one of these novel agents is Chlorophyll-a, also referred to as a chlorophyll-lipoid complex. Dermatology researchers from the Seoul National University College of Medicine at Seoul National University (Korea) sought to evaluate the clinical efficacy and safety of chlorophyll-a PDT for acne.
Eight treatment sessions were performed in 24 individuals over a four-week period in people with acne on both sides of the face. After treating half the face with a cream containing Chlorophyll-a, that half was exposed to a blue and red light-emitting diode, while the other half received only phototherapy using an LED light.
The lesion counts and acne severity were assessed by an examiner who was blinded as to the treatments received. Facial acne improved on both treated sides. However, on the side treated with chlorophyll-a PDT, there were significant reductions in acne lesion counts, acne severity grades, and sebum levels compared with the side treated with phototherapy alone.
These findings suggest that chlorophyll-a PDT for the treatment of acne can be effective and safe with minimal side effects, as reported online ahead-of-print in the 12 June 2014 Journal of the American Academy of Dermatology. Researchers at the First Hospital of China Medical University in Shenyang, China, recently conducted a comprehensive review of the evidence concerning the efficacy of PDT for treating acne. Their review included 14 randomized controlled trials and a total of 492 patients.
The Shenyang team concluded that PDT shows good efficacy in the treatment of acne with acceptable side effects. A combination of ALA-PDT with red light was found to be the optimal choice. Nevertheless, the authors state that more RCTs are needed to more reliably determine the optimal types and concentrations of photosensitizers and light sources, and the duration of light activation and incubation, as reported online ahead-of-print in the 5 June 2014 European Journal of Dermatology.
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Asayama-Kosaka S, Akilov OE, Kawana S. Photodynamic Therapy with 5% δ-Aminolevulinic Acid is Safe and Effective Treatment of Acne Vulgaris in Japanese Patients. Laser Ther. 2014 Jul 1;23(2):115-20.
Song BH, Lee DH, Kim BC, Ku SH, Park EJ, Kwon IH, Kim KH, Kim KJ. Photodynamic therapy using chlorophyll-a in the treatment of acne vulgaris: A randomized, single-blind, split-face study. J Am Acad Dermatol. 2014 Jun 12. [Epub ahead of print]
Zheng W1, Wu Y2, Xu X2, Gao X2, Chen HD2, Li Y2. Evidence-based review of photodynamic therapy in the treatment of acne. Eur J Dermatol. 2014 Jun 5. [Epub ahead of print]
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