Treatment of acne with photodynamic therapy.

Photodynamic therapy (PDT) with aminolevuninic acid (ALA) and methylaminolevulinate (MAL) can improve acne vulgaris. Topical application of these molecules results in significant build-up of porphyrins in sebaceous glands and the efficacy of PDT in acne is believed to be related in part to a decrease in sebaceous gland activity following light activation of the photosensitizer. Clinical development of photodynamic therapy with ALA or MAL for the treatment of acne has been limited by complexity of the PDT procedure, the pain caused during light exposure and by the intense phototoxic reaction observed in the days following treatment. These side effects can be significantly decreased by using a shorter incubation time, avoiding occlusion or using a lower light fluence but several studies have suggested that when milder PDT conditions are used the efficacy is not as good and is mostly driven by the effect of light alone. Using current knowledge many physicians are offering PDT as an alternative to their patients with acne. However more research is needed to determine the optimal treatment parameters and to design strategies to improve treatment tolerability.