This leaflet aims to provide you with information on what you might
experience and how to care for your skin, particularly the treatment
site, following Conventional (red light) Photodynamic therapy (PDT).
What is photodynamic therapy?
This is a treatment for certain types of lesions such as actinic
keratosis and basal cell carcinoma which involves the application of
a photosensitising gel and illumination under a red light.
The gel starts a process which helps destroy the damaged skin cells
and leave the healthy skin cells intact when the red light is applied.
What do I need to do before my appointment?
Your doctor or nurse may ask you to apply a moisturiser daily for
the week before your appointment to the affected area to soften any
crusts/scales on your skin.
What can I expect on the day of treatment?
In total, your PDT treatment takes around 4 hours, although there will
be an interval of 3 hours between application of the gel and the redlight
illumination. You may be able to go out or even home between
the two parts of the process, but your doctor or nurse will discuss
that with you.
When you arrive at the hospital/clinic, one of the team will explain
the procedure and ask for your consent to the treatment. The area to
be treated will be cleaned with an alcohol wipe, then any remaining
crusts/scales will be gently removed, and the area marked up.
The gel will be applied to the area followed by 1 or 2 dressings to
keep any light out. As the gel is activated by light it is important to
make sure that no light reaches the area too soon.
It takes around 3 hours for the gel to take effect and the staff will
inform you of what time you need return to the clinic for the light
illumination.
After 3 hours, the dressings will be removed, and any excess gel
wiped off. You will be asked to lie or sit in a comfortable position.
The area will be illuminated by a lamp that shines a non-thermal red
light. The lamp will be positioned about 6 cm from the lesion(s). You
will be given special goggles to protect your eyes from the red light
and the procedure takes around 10 minutes. During that time, you
may feel some tingling and discomfort. This is perfectly normal and
is a result of the gel reacting with the light to destroy the damaged
cells. The operator can cool the area with water or fan to help relieve
these symptoms.
Please avoid sun exposure on the treated areas and surrounding
skin for approximately 48 hours following treatment. This can be
ensured by keeping the treated area covered with a dressing or
clothing (e.g. a hat). In most cases, an appropriate dressing will be
applied by the nurse, and this must be kept in place for 48 hours.
What happens next?
You can also expect the area to be inflamed and crusty for up to
two weeks while the damaged cells are shed and replaced with
new healthy ones. Some lesions, such as basal cell carcinomas,
need to be treated twice, 7 days apart, and you will be told if this is
necessary for you.
Your doctor or nurse will normally ask to see you again in around 3
months to assess the results and will decide if treatment may have to
be repeated at this time.
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Author Dermatology Department
Approved by Dermatology Business Meeting
Date of Publication 03/09/2024
Reference No PL/082 (v8)
Review Date 01/09/2027
