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Photodynamic therapy (PDT)

Photodynamic therapy activates a topical drug using a light, producing a chemical reaction that reduces acne, acne scars, wrinkles and other skin conditions.

Before You Go

Questions to ask your doctor:

  • Can lasers, peels, and injections interfere with PDT?
  • What are the best home creams and products to use in between sessions?

Pre-procedure prep for Photodynamic therapy (PDT): Photodynamic therapy makes use of a photosensitizing cream (Metvix) or liquid (Levulan) and light, but the first needs to be smeared on in advance. Depending on what condition and body part you're treating, you may need to apply the drug an hour to a full day before your light treatment. The only person who can give you exact instructions is your physician.

On the day of treatment: You may be asked to show up to your PDT appointment with a clean face. That means if you use lotions, sunscreen, and makeup, you'll have to skip your daily routine for the day.

What To Expect

Photodynamic therapy can be administered in a physician's office or in a clinical outpatient setting. As for the actual treatment, here's what you can expect. Once your skin is washed, your dermatologist will apply the chosen topical drug to your oily, pimply, and blotchy skin patches. Then, you wait.

This at least hour-long lag is known as the incubation period, allowing the photosensitizing agent time to seep into your skin. When it comes time for the light therapy, this can be done comfortably from a sitting or reclining position. Your skin may appear red, patchy, and swollen after treatment.

Who should do it: Dermatologists who offer photodynamic therapy should be board-certified members of the American Academy of Dermatology.

If you think PDT may be right for you, talk to a dermatologist who can customize your treatment and prescribe the right cream/lotion-and-beam combo for your skin.

Duration: If the PDT is aimed at your forearms or legs, the incubation period (the time in which the photosensitizing cream is left on your skin) can take up to 18 hours. (Don't worry; you won't have to wait in the office the entire time.) Once the drug is fully absorbed, the PDT light is used to activate the photosensitizing agent for five to 45 minutes.

How Painful Is It?

The photosensitizing agent shouldn't cause any discomfort, but the light source can give you a warm, tingling, hot, or burning sensation. This tends to happen around the third to seventh minute, when the light-sensitizing drug becomes active. (At least you know it's working!) Pain level is a 2 out of 10.

Options for anesthesia: No other sedation or anesthesia is necessary for PDT. Most recipients experience mild discomfort, or none at all. Fans may be used to cool and soothe the skin if you are particularly sensitive.

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