Photodyamic Therapy (PDT)

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What is Photodyamic Therapy?


PDT is a therapy that combines the application of a light-sensitizing medicine called aminolevulenic acid (ALA) to the skin. This medicine is more selectively absorbed by sun-damaged skin. The area treated is then exposed to a light that activates the medicine and destroys sun-damaged cells including pre-skin cancers. This treatment is an alternative to other comprehensive treatments for pre-skin cancers, such as Efudex  or Aldara. It has the advantages of a shorter treatment period and a usually shorter recovery period. It does cause light sensitivity that requires strict sun avoidance for about 2 days.


What Does the Treatment Require?


This treatment is performed in our office and requires a treatment period of about 2-3 hours. The area to be treated is cleaned and then ALA is applied to the skin. Depending on the period that the ALA is allowed to incubate, a topical anesthetic may be applied to the skin.  After the incubation period, the ALA is activated with either the BLU-U light or the V-Beam laser or a combination of the two light sources for a period of less than 20 minutes. During this light exposure, the area treated may sting or burn. Following the light treatment, the skin will have a soothing cream and a physical sunblock applied.


What Can I Expect After Treatment?


The area treated will feel like a sunburn and will remain red for a period of days and then will peel. Patients are usually completely healed within 7-10 days. During the first 2-3 days, patients may experience swelling of the area around the lips and eyes. This can be decreased by cool compresses. Once healing is complete, patients should notice that pre-skin cancers have decreased or have been eliminated. Patients also frequently notice that the texture and tone of their skin is improved. Some fine lines and wrinkles may be diminished.  ALA PDT in conjunction with the VBeam laser can decrease telangectasias (redness and blood vessels) and be used to decrease the symptoms associated with rosacea.


What Are the Disadvantages of PDT?


The ALA applied to the skin continues to make patients light sensitive for about 2 days requiring strict avoidance of the sun and bright (such as halogen) lights. There is some discomfort associated with the light or laser application and following treatment the skin may feel like a sunburn. Patients who have porphyria are not candidates for treatment. Patients who are on photosensitizing medication may need to discontinue this medication for a short time prior to treatment. Patients with a history of cold sores will need to take medicine to suppress an outbreak during treatment. AS with any treatment for pre-skin cancers, treatment may need to be repeated to obtain optimum results.


What Are the Advantages of PDT Over Other Treatments for Sun Damage and Pre-skin Cancers?


Most patients who have used Efudex to treat pre-skin cancers preferred PDT because the duration and intensity of side effects were less with PDT. The length of treatment is also shorter and does not require the application of medicine repeatedly by the patient. Liquid nitrogen (or freezing) can sometimes leave white spots or uneven skin tone whereas PDT usually evens out skin tone.