Pdt Blue Light: What It Is and What to Expect
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor provides Pdt Blue Light?
Blue light photodynamic therapy is usually performed by a dermatologist. Some plastic surgeons and family doctors with special training also offer it. The doctor must be trained to use the light device and the skin solution that goes with it.
What it is
Photodynamic therapy (PDT) uses a special light to treat damaged skin. The doctor applies a liquid medicine that soaks into damaged cells and makes them sensitive to light. A blue light then activates the medicine, and the treated cells break down over the next day or two.
Why a doctor might recommend it
Doctors most often use blue light PDT for actinic keratosis, rough, scaly patches caused by years of sun exposure. These patches are not skin cancer, but they can turn into squamous cell carcinoma over time, so treating them lowers that risk. It is also useful when there are many patches, since treating each one separately would be hard.
How to prepare
- Avoid strong sun exposure and tanning beds for a few days before the visit.
- Ask your doctor which skin products to stop using on the treated area.
- Arrange time indoors for the next day or two, away from sunlight and bright indoor light.
What happens during it
The visit usually takes about an hour. The skin is cleaned, the liquid medicine is applied, and it sits for under an hour to a few hours. The blue light is then placed over the skin for several minutes, often feeling warm, tingly, or mildly stinging, before the medicine is washed off.
Recovery
The treated skin usually turns red and may swell, blister, or peel for several days. Most people look and feel much better within a week. The most important rule is to stay out of the sun and away from bright lights for at least the first day or two, because the medicine stays active in the skin.
Risks and side effects
The most common side effects are redness, swelling, stinging during the light, and peeling. Some people develop small blisters or a temporary change in skin color. Infection and scarring are rare but possible, and the treated area will be very sensitive to sunlight at first.
Who performs it
A dermatologist performs this treatment in most cases. Some other specialists and trained primary care doctors offer it too. When you look for a provider, ask how many of these treatments they have done.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either one can be a good first stop for rough or scaly skin patches. If your skin needs blue light PDT, they will refer you to a dermatologist and can help with follow-up.
Common questions
Does the treatment hurt?
Many people feel warmth, tingling, or stinging while the blue light is on. This usually stops soon after the light is turned off. Tell your doctor if it becomes hard to tolerate.
How many treatments will I need?
Some people need only one session, while others need a second one later. It depends on how many patches you have and how your skin responds.
Can I go outside after the treatment?
Stay out of direct sunlight and bright indoor light for at least the first day or two. After your doctor says it is safe, use sunscreen and protective clothing.
Sources
- American Academy of Dermatology - Actinic keratosis: Diagnosis and treatment
- MedlinePlus - Blue discoloration of the skin: MedlinePlus Medical Encyclopedia
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
