Dermatology Clinic

Photodynamic Therapy

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Stanford Dermatology: Photodynamic Therapy

Photodynamic therapy (PDT) is an FDA approved treatment for precancerous skin lesions called actinic keratoses. Other treatment options for actinic keratoses (some of which you may have had before) include cryotherapy (freezing of individual lesions) or topical therapy with creams (fluorouracil, imiquimod or diclofenac) that you apply at home for 2-16 weeks. The advantage of PDT is that it requires less downtime compared with topical therapy regimens; however like the other therapies for precancerous lesions, multiple treatments may be necessary.

What are the most common side effects?

How to prepare for procedure day

  1. Please bring a wide-brimmed hat, sunglasses for treatment on the face and a long-sleeved shirt for treatment of your arms.
  2. Please make sure that your doctor has an updated list of all of your medications prior to the procedure, including any over-the-counter medications or herbal remedies that you are taking. .
  3. Please let your doctor know if you have a history of cold sores or fever blisters because they may want to give you medication to prevent an outbreak after your procedure. 
  4. Please let your doctor know if you have any urgent obligations that would require you to travel in the 48 hours post-procedure or if you have any events (i.e. weddings, vacations, or other important social engagements etc.) in the weeks following your procedure date as these may be reasons to reschedule your procedure.
  5. The incubation time (time between the application of the medication and when the light treatment is performed) varies. Your physician and/or nurse will guide you regarding this length of time. Because the incubation time can be at least 2-4 hours, consider bringing a book/magazine and drink/snack as there will be downtime during the incubation period.

What can I expect?
On the day of the procedure:
You will be asked to wash the treatment area, and we will use a scrub to further cleanse your skin. Then a topical medication (aminolevulinic acid 20% solution) will be applied to the treatment area. After the medication is applied, it will incubate on your skin for anywhere from 1 to 16 hours. It is important that you avoid sunlight and bright indoor lighting during this time. There is no pain involved with the application of the medication. Some patients may experience slight tingling of the skin.


During the treatment:
You will be asked to wear protective goggles. Your skin will be exposed to 16 minutes and 40 seconds of bright blue colored light. You will likely experience burning, tingling, stinging, and mild to moderate pain. These symptoms can be minimized by blowing air (with the hand-held fan) over the skin, applying ice packs, and by taking breaks in treatment (only if really needed).

After the treatment:
Burning, tingling, prickling, stinging, and limited pain may be noted within the first 24 to 48 hours of treatment. Treated areas may turn bright red and/or become swollen. Afterwards, you may notice peeling and significantly dry skin. Sometimes the treated area surrounding actinic keratoses turns red but this should improve with time.
To prevent a severe sunburn-like reaction you must strictly avoid direct sunlight, indirect sunlight through windows and skylights and even bright indoor lighting for the next 48 hours (sitting in a dimly lit room away from windows is best; computer screens and televisions are okay). In addition, applying sunblock (containing either zinc oxide or titanium dioxide) to the treatment area every 2-3 hours during the day is strongly encouraged. Keep in mind however that sunblock will not fully protect the area from the sun if you were to go outside. 

How do I take care of my skin after the treatment?
If you notice a burning or tingling sensation (similar to that noted during the treatment), find a location with less light. Besides being careful with bright lights, moisturizing the skin with bland emollients will help with some of the burning sensation and dry skin. Recommended emollients include Cerave or Cetaphil creams, Aquaphor or plain hydrolatum. You can even try keeping the creams in the refrigerator and apply the chilled emollient to the affected areas. Washing the treated areas with a gentle soap (such as Dove or Basis) or non-soap cleanser (such as Cetaphil or Purpose) and lukewarm water is recommended.  Pat the area dry (rather than rub) with a soft cotton towel, and immediately afterwards apply a liberal amount of one of the above recommended bland emollients. Reapply bland emollient/sunblock every 2-3 hours during the first week. 

In some cases, your physician may prescribe a topical steroid to use for a few days if you develop significant redness and swelling.

Lastly, taking ibuprofen as directed on the bottle (if you don’t have any problems with taking ibuprofen normally), within a few hours of treatment, can help relieve the initial sunburn like reaction.

Call us with any questions or concerns: 650-723-6316.

Download the PDT handout here.


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