Photodynamic Therapy

Photodynamic Therapy is primarily used to treat such skin conditions as actinic keratosis, basal cell carcinoma and Bowen disease. It has been used off-label for skin rejuvenation as well as acne although not approved by the FDA for these indications. In essence, photodynamic therapy is the enhancement of the effects of commonly used lasers and light sources with the so-called photosensitizing agents. These agents work by absorbing visible light and emitting it on lower energy wavelengths (usually infrared) and/or generating free radicals and other unstable and locally damaging chemicals. They can enhance the destructive effects of the laser or intense light on the skin, which, if properly targeted, can be used to remove lesions and induce skin remodeling. The most common photosensitizing agents are 5-aminolevulinic acid (ALA) and methylaminolevulinate (MAL). Common light sources include intense pulsed light (IPL) and Blu-U light. Unfortunately, the optimum settings for skin rejuvenation are unknown. Physicians have to empirically determine optimum number of sessions, filters, irradiance, frequency and so forth. As a result, outcomes tend to be variable and inconsistent. Studies are needed to determine best practices and full value, if any, of enhancing nonablative laser/light therapy with photosensitizing agents.