Photodynamic therapy (PDT) is a procedure that uses a photosensitizing drug to apply light therapy selectively to target pre-skin cancer, acne and sun damage.
What it can help/cure
PDT can help clear the skin of actinic keratoses which are premalignant growths in sun-exposed areas, mainly the face, chest, arms and hands. It is also effective for moderate to severe acne. A series of treatments can put acne into remission for months as well as reversing some scarring without taking oral medications. When used with lasers or sun-damaged skin, the results achieved are better and faster than when using the light alone. There are many less common conditions that PDT can be used for, including hidradenitis suppurativa, Bowen’s disease, superficial basal cell carcinoma and others.
What to expect before, during and after the procedure
The skin will be cleansed thoroughly; practitioners will perform an acetone scrub, microdermabrasion or mild chemical peel immediately before application of the drug to increase penetration. The aminolevulinic acid, a clear liquid, will be applied to the entire surface of the skin that is to be treated. This will incubate, or be absorbed, for 30 minutes to 3 hours, depending on your condition and the light used. Multiple different light sources can be used including blue light, red light, intense pulsed light, pulsed dye laser and some others. Occasionally you will feel some burning discomfort during the treatment lessened by fans or cold air. After the treatment the skin involved will be extremely light sensitive for 48 hours until the medication is completely metabolized. Hats, scarves and thick sun block with zinc oxide and light avoidance are required to protect the skin during that time. Most of the time, some redness and mild peeling occur over the first two to three days. Occasionally, there can be a burning discomfort for 24 hours and more prolonged peeling and redness five to 14 days can occur.
Complications that can occur
Although not a “complication," the “PDT effect” is the most common problem associated with this procedure. “PDT effect” is the redness and peeling that occurs after the procedure. This can be pronounced with significant crusting and some discomfort. Severe reactions occur usually for one of two reasons. If someone has a large number of pre-skin cancers, much more of the drug will be absorbed and there will be a stronger reaction. People sometimes think that driving in their car is “staying inside” or they are going to just run a few errands, but the sun’s rays penetrate through window glass and even high SPF sun block is not adequate protection during the first 48 hours. However, the PDT effect resolves within one to two weeks. People who have severe reactions often have excellent results.
Questions to ask your dermatologic surgeon
Ask how many treatments they think you will need and what to expect. Ask them what kind of maintenance treatments you can have and how to keep your skin in good condition after you have completed the treatment course.
For more information and referrals
For more information on skin conditions and treatments, along with a list of ASDS members in your state, please visit the Find a dermatologic surgeon section of our website.