What is PDT?
Photodynamic light therapy (PDT), also known as Red or Blue Light, is a “field type” treatment
for actinic keratoses. Actinic keratoses (AKs) are red, rough, scaly spots on the skin. AKs are
considered a “pre-cancer” or a precursor lesion because they have the potential to progress into
squamous cell carcinoma (SCC). Because predicting which AKs will evolve into SCC is unreliable
on a clinical basis, conventional wisdom suggests all AKs be treated. For every one actinic
keratosis on the surface, there can be 5-10 underneath the surface, therefore, when patients
have numerous actinic keratoses in one area, we recommend treatment with a field treatment.
Field treatments can include red light, blue light or topical creams.
PDT combines a photosensitizing drug (Levulan or Ameluz) and a type of light, Blue or Red Light.
These lights are safe light and are within the visible light spectrum. Precancerous cells absorb
the medication and make these cells extremely sensitive to the light. Once the AKs are exposed to
the light, a chemical reaction occurs that leads to the eventual destruction of the precancerous
cells. PDT was approved by the FDA in 2001.
What are other options for treatment of actinic keratosis?
We will work with you to design a treatment that is most effective for your condition. Alternate
treatments may include a combination of PDT, topical creams and/or liquid nitrogen.
What should I expect during a PDT treatment session?
Please arrive to the clinic with the area that is to be treated clean and free of any lotions,
makeup or sunscreen. We advise that you eat your meals at your regularly scheduled time and take
your medications as you normally would. If you use topical retinoids (e.g. Renova or Retin-A) or
alpha-hydroxy acids, discuss with your provider prior to scheduling your treatment. Additionally,
if you have a history of cold sores, or “fever blisters”, please inform your provider prior to
scheduling your appointment.
We ask that you bring a wide brimmed sun hat, sunglasses and a scarf. When you arrive at the Skin
Surgery Center, we will have you wash your skin with soap and water. We will prep the skin with an
alcohol scrub and possibly debride some thicker lesions. Next, we will apply the photosensitizing
medication. This medication will stay on for 60-180 minutes. After the waiting period, we will
have you wash your face or other treated area with soap and water and position you under the light.
The treatment time under the light ranges from 10 minutes to 16 minutes and 40 seconds per area.
While under the light, most patients feel a sensation of heat in the treated areas. Typically
patients will describe this as a “hot” or “burning” sensation. The discomfort may be alleviated
with use of a bottle of water to spritz on the skin as well as a fan. Typically the discomfort
dissipates or levels out halfway through the treatment under the light. Every person, however,
reacts differently. It may be helpful to have a support person, such as a spouse or friend,
with you to help with the fan and spritz bottle.
It is very important that patients avoid all exposure to natural sunlight and strong artificial
light for 48 hours after treatment. Since the medication is active for 48 hours, any additional
sun or light exposure can result in a continued and stronger than desired reaction. This can
include exposure to light from a tablet or computer.
How is recovery after PDT treatment?
Recovery is relatively uneventful for most patients. Typically within the first 72 hours, patients
have a mild-moderate sunburn like reaction with redness, swelling and tightness. After 72 hours,
many patients will have dryness and scaling of the skin. These symptoms usually resolve in 10 days
time. A small percentage of patients will experience more significant reactions that may take up to
2 weeks to resolve.
VERY IMPORTANT REMINDER. It is important to remember even brief (1-2 minutes) sun exposure during the
immediate post treatment time can cause a much more severe reaction. This can include tasks such as
getting the mail or walking to the car. It is best to plan to stay indoors and avoid any direct sunlight
for 48 hours. If you must go outdoors during the 48 hours following light treatment, it is imperative that
you use proper sun protection including sunscreen and hat or cover up clothing.
Can I return to work or school?
This depends on your job duties, your comfort level and light exposure. Many patients are able to return to work
or school within 72 hours after treatment with PDT. It is important to note your skin may appear very red initially.
Patients have informed us that they frequently have to explain their redness is due to a treatment.
Is there pain after PDT?
No two individuals and their skin are exactly the same and therefore individual reactions and tolerance to
discomfort levels vary. Most patients report skin redness and irritation including a tight feeling to their skin.
This discomfort is usually improved with frequent application of bland topical emollients such as Aquaphor. A small
number of patients report they have little pain or peeling.
Ibuprofen is a good medication to take to alleviate any discomfort. This should be taken with food as directed on
the medicine bottle (usually 400mg every 8 hours) and only if you know that this is a medication that you can
Will my AKs recur?
While PDT is a very effective treatment, many individuals continue to need periodic treatments for AKs over time.
Individuals have layers of sun damage from cumulative years of sun exposure that rise to the surface over time.
Patients with extensive sun damage will likely need periodic treatments (e.g. twice yearly to every 5 years) for
these layers of sun damage. The skin of every individual is different as is the amount of damage each patient has
Where is this treatment offered?
Currently, PDT with red light is offered in Bellevue and with Blue light in Seattle. If you are found to be
a candidate for PDT and it would be more convenient to receive treatments elsewhere, we would be happy to help
identify someone qualified to assist. Most patients will need 1-2
treatments of light. The treatments are spaced 2-8 weeks apart. Patients should plan on being in our office for
2-4 hours. Patients should come prepared to wait in the waiting area and bring a broad-brimmed hat to wear during
and after the treatment.
Will my insurance cover this?
Currently, PDT is most effective for treatment of the head and neck and as such is a covered treatment for
most insurances. If patients are interested in treating other areas, this may be arranged.