Photodynamic therapy in dermatology: current treatments and implications.

This article provides an update on photodynamic therapy by discussing each of the essential components in sequence: mechanisms of action, common photosensitizers, typical light sources, and indications. In dermatology, photodynamic therapy (PDT) is mainly used in the treatment of superficial skin cancers: actinic keratoses, Bowen's disease and superficial basal cell carcinomas. However the range of indications has been expanding continuously. PDT is also used for the treatment of other oncological indications and non-malignant conditions such as acne vulgaris and photoaged skin. The 5-aminolevulinic acid (ALA) or its methyl ester (MAL) is applied topically as photosensitizer before activation with visible light. The advantages of topical PDT are: ability to treat multiple lesions simultaneously, low invasiveness, good tolerance and excellent cosmetic results.