Photodynamic Therapy (PDT)
What is PDT?
PDT is a treatment performed with a topical photosensitizing agent called Levulan® (5-aminolevulinic acid or ALA) which is applied to the skin for a certain length of time based on what body area is being treated. The Levulan® is absorbed by a target tissue and it becomes activated when exposed to a certain wavelength of light. A chemical reaction occurs which produces free radicals which damage the target tissue. The Levulan® is only picked up by abnormal cells so this reaction allows controlled destruction of the abnormal cells.
What is PDT used for in dermatology?
• Moderate to severe acne-
PDT is an FDA approved treatment for acne. The treatment kills the Propionibacterium acnes which is responsible for inducing inflammation in acne lesions. PDT also has a unique ability to decrease the size of the oil glands which reduces oil production.
• Actinic Keratoses- Sun-induced pre-cancerous growths
PDT is one of the many ways that actinic keratosis can be treated. PDT allows selective tissue destruction of these pre-cancerous cells. Although the levulan may be absorbed all over by the skin in the treated area, more of the levulan is absorbed by these abnormal cells and when the levulan is activated by the light source these abnormal cells are destroyed and the normal cells are preserved. Once the treated areas have healed following PDT, the areas are reexamined to see if any additional treatments or biopsies are needed.
• Photorejuvenation- Sun damage, brown spots, redness
Intense Pulsed Light (IPL) is now the gold standard of non-ablative treatments. IPL with the addition of Levulan® applied one hour prior to the treatment gives a much more enhanced effect than IPL alone. One IPL treatment with Levulan® is equal to 3 IPL treatments without the Levulan®.
How many treatments can I expect?
To achieve maximum improvement of pre-cancerous growths, sun damage, redness and mottled pigmentation a series of 2-3 treatments spaced every 4 weeks is very effective. Treatments need to be done at periodic intervals in the future to maintain the rejuvenated appearance of the skin.
What should I know about PDT treatments?
Following PDT, the treated areas can appear red and swollen with some peeling for 5-7 days. Temporary swelling of the lips and tissue around the eyes can occur for a few days. Darker spots (age spots) can become temporarily darker before peeling off leaving normal skin which can take 7-10 days. Even though Levulan® is washed off the face after the procedure it remains active in the skin for 48 hours so patients must remain completely indoors for 2 days following the procedure or the skin will burn. This is a very important thing to remember when scheduling your treatment.