Photodynamic therapy

Generic name: Photodynamic therapy

Brand(s):

Function / Purpose:
Primarily used to treat such skin conditions as actinic keratosis, basal cell carcinoma and Bowen disease. Has been used off-label for skin rejuvenation as well as acne although not approved by the FDA for these indications.

Details:
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 wavelengths (usually infrared) and/or generating free radicals and other unstable and locally damaging chemicals. There effects augment the destructive impact 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).

Photodynamic therapy is an approved treatment for actinic keratosis and has been shown effective in a number of studies for basal cell carcinoma and Bowen disease. It is not approved for skin rejuvenation but has been used off-label by dermatologists for that purpose. The photosensitizing agent is usually ALA; common light sources include 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, fluence, 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 rejuvenation treatments with photosensitizing agents.

Acne is another off-label use of photodynamic therapy. Studies indicate that photodynamic therapy causes some degree of destruction of sebaceous glands, thus decreasing oil production and potentially leading to long-term improvement in acne. In most studies, photodynamic therapy with ALA and IPL or Bru-U has been used for acne. However, optimal settings and protocols for photodynamic acne treatment remain to be determined.