Photodynamic Therapy (PDT) for Actinic Keratoses

PDT is also known as “blue light”. It is used for the treatment of actinic keratoses (AKs). AKs are pre-cancerous lesions which are usually pink and rough like sandpaper. If left alone they have the potential to develop into squamous cell carcinoma. In an effort to remove these lesions and prevent skin cancer development PDT can be used. It is beneficial when one would like to treat an entire affected area. It can clear the precancerous changes while providing a cosmetic improvement in the appearance of the skin.

How does it work?

PDT involves the application of a photosensitizer to the skin. This is a cream that is placed on the area to be treated (usually the face, neck, scalp, forearms or hands) and then left to “incubate”. This incubation period can vary depending on the patient and location being treated, however it is typically 2-3 hours. After the cream is applied in the office you may leave and then return after the specified incubation period. During this incubation period the cream that was applied is absorbed by the AKs and is converted into a light sensitive by-product. We then activate this chemical by placing you under the blue light for 16 minutes and 40 seconds.

What should I expect?

• During the blue light treatment you should expect some discomfort and burning. This is alleviated by use of a handheld fan and usually improves after about 6 minutes. Once the treatment is finished you will wash the treated area and apply sunscreen.
• The treatment area should become red and start to peel that evening. This peeling may last for 1-2 weeks. It may be a mild or significant reaction. Given that some reactions will be significant with peeling lasting for up to 2 weeks we recommend that one has no significant social or work events in the 2 weeks after the treatment.
• As the areas peel you should avoid scrubbing the area. Instead gently cleanse with soap and water then apply Vaseline or Aquaphor to the healing areas several times daily.
• It is necessary to exercise strict sun avoidance for 48 hours after the treatment. The photosensitive chemical remains in the skin for about 40 hours after it is applied. UV light as well as strong overhead lights will continue to activate the cream for the first 2 days, eliciting a burning sensation.
• Cold sores (also known as fever blisters or herpes simplex infections) can occur after PDT in people that are prone to them. It is important to tell your provider that you may be predisposed to cold sores prior to the treatment so that anti-viral prophylaxis is used.
• One can expect an improvement in the precancerous changes as well as the appearance of the skin following PDT. It removes many of the imperfections caused by UV light exposure over time leading to a brighter smoother complexion. Some patients will require 2 or more treatments.