Photodynamic therapy (PDT) is a FDA approved treatment for actinic keratoses (AKs). It is used when there are multiple AKs that need to be treated in an area. It works by applying a topical medication called aminolevulinic acid to the skin. This medication is preferentially taken up by the precancerous cells and is converted to a substance which is activated by the blue light. When the blue light is turned on, it will destroy the precancerous cells which have taken up the medication.
In general, one area will be treated at a time (i.e. scalp, face, or arms and hands). The topical medication will be applied to the affected area and it will be left in place for approximately 1 hour. A blue light will then be placed over the affected area. You will be under the blue light for almost 17 minutes. During the treatment you may experience some tingling, burning and pain, but this is tolerable for most people.
After the treatment, it is extremely important to practice strict sun avoidance for 48 hours. The medication will remain on your skin for this period of time and we do not want any further activation of the medication to occur. If you notice that the treated skin is tingling or burning after your treatment, then you need to be careful that you are not exposing yourself to too much light. Remember, you will be exposed to sunlight through windows, so be careful with windows in your house, office or car. Please bring protective clothing with you to your light treatments. For example, if we are treating your scalp or face, make sure you bring a wide-brimmed hat, sunglasses and even a scarf or bandana. Bring gloves and wear a long sleeve shirt if we are treating your arms and hands. You can expect to be in our office for about 2 hours for your treatment. Bring some reading material or anything else you might like to keep you entertained during your wait.
After your treatment you can expect increasing redness and inflammation for approximately 2 days. Cool compresses and topical emollients (i.e. Vaseline petroleum jelly, aquaphor, cetaphil cream or cerave cream) may be helpful. Over the next 7-10 days, the redness should subside. Remember to practice strict sun protection for 48 hours. After this, you should wear daily sunscreen and practice sun protective measures as usual.
It is usually recommended that a second treatment be performed 8 weeks later to achieve maximal response.