AAD 2009: Combination Laser and Photosensitizer Improve Acne Treatment

Bob Roehr

March 17, 2009

March 17, 2009 (San Francisco, California) — Fine-tuning the combined use of photodynamic therapy and photosensitizers can improve treatment for acne, according to a report here at the American Academy of Dermatology 67th Annual Meeting.

Yale University School of Medicine professor Macrene Alexiades-Armenakas, MD, PhD, explained that "blue-light therapy alone results in a 25% to 52% acne improvement rating following a series of treatments. But the problem is that excessive numbers of treatments have been required, the effects have been modest, and recurrences are common."

Red light alone or in combination with blue light has similarly resulted in a modest response, although combined treatment with the 2 lasers has almost doubled the response rate. The goal of this pilot study "was to further boost the acne clearance rate while decreasing the number of treatments to 1 or 2," Dr. Alexiades-Armenakas said. This limits the time and cost to patients.

The study involved 10 patients with mild to severe cystic acne resistant to traditional treatments. Patients were treated with the photosensitizer topical 5-aminolevulinic acid (ALA) and allowed to incubate for 1 hour. Numbing cream was applied, and both blue- and red-light lasers — 1450 nm diode laser and the pulse-dye laser — were used off label.

"The preliminary results show a higher clearance rate of the acne per treatment, decreased pore size, and lower sebum production," Dr. Alexiades-Armenakas said.

A control group of 4 patients was treated with conventional systemic or topical therapy, or with lasers, but without ALA photodynamic therapy. None of them achieved complete clearance of their acne.

Using before and after photos of patients, she noted "not just a dramatic clearing of the acne cysts," but also an improvement in skin texture that is "much more dramatic" than occurs with the use of either laser alone.

"The 1450-nm wavelength is very highly absorbed in lipids, so there is a great deal of absorption in the sebaceous follicle," Dr. Alexiades-Armenakas explained to Medscape Dermatology. The action of this laser shrinks the oil glands in much the same way as isotretinoin does. "It gets to the target of acne."

The pulse-dye laser works in a similar manner and also through a mechanism of apoptosis. "There is an independent effect on the blood vessels in the upper layer of the skin. We must remember that acne is an inflammatory disease; there is an immune-system component." Dr. Alexiades-Armenakas believes that the procedure reduces the number of cellular targets that stimulate the inflammatory immune response, dampening that process.

Harvard University Medical School researcher Alexa Boer Kimball, MD, said that combining existing interventions is a good way to improve response and patient tolerability. This study is a useful addition toward that end.

The pilot study did not receive commercial funding. Dr. Alexiades-Armenakas and Dr. Kimball have disclosed no relevant financial relationships.

American Academy of Dermatology (AAD) 67th Annual Meeting: Presented March 8, 2009.


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