How Does PDT Work?
Photodynamic therapy (PDT) in dermatology is a treatment that uses a special topical photosensitizing medication applied to the skin that is then activated by a special blue light in order to provide the desired benefit. PDT is FDA-approved to treat pre-cancerous spots called actinic keratoses. It can as well be used off-label to treat a variety of other conditions including acne, rosacea, and sun damage.
In treating pre-cancerous actinic keratoses, the medication is preferably absorbed by the hyper-metabolic abnormal cells. The photosensitive agent is turned on when the light shines on the skin and the abnormal cells are destroyed.
The treated area is red like a sunburn for several days and then the skin peels for about a week. During the first 48 hours after treatment the skin is still chemically sensitive to light so one must plan to stay indoors away from bright windows for that period of time.