Photodynamic therapy (PDT) also commonly known as Blue light therapy is an effective option for treatment of actinic keratosis. Actinic keratosis often appear as rough slightly red to pink spots on sun exposed skin; are commonly referred to as “pre-cancers.” If we were to look at the actinic keratosis microscopically we would see abnormal cells in the upper most layers of the skin. If left alone some of these abnormal cells can grow deeper at which point they would be classified as a skin cancer (squamous cell carcinoma).
Patient undergoing Blue Light Treatment:
There are several methods to treat actinic keratosis with the most common being application of liquid nitrogen (cryotherapy/freezing), or application of a prescription cream, or photodynamic therapy. PDT may be utilized to treat individual actinic keratosis but more commonly is used to treat an entire area such as the face or scalp referred to as field therapy which is one of the advantages of PDT over cryosurgery. Such field treatments can be beneficial as often there are subclinical, not yet visible, abnormal cells in areas where actinic keratosis form so by treating the entire area instead of just the spot, one can achieve better long term results. Furthermore, there is less risk of scarring (leaving white spots) with PDT compared to liquid nitrogen. Compared to the creams which application requires days or weeks, PDT gets the treatment over with in one day. Depending on patients medication insurance, the prescription creams often have more out of pocket cost compared to PDT which is covered as an office procedure. Most patients who have been experienced both treatment with a prescription cream and PDT have preferred the PDT treatment because its treatment course and resultant inflammation is shorter. The down side of PDT which will be discussed more in a moment is the pain incurred during treatment, and being sensitive to bright light (photosensitive) after the treatments.
The PDT treatment is a 2 step process. The first step involves application of a medication called Levulan to the affected area to be treated. The Levulan is preferentially absorbed into the cells of the actinic keratosis. This is painless. After application, time is allowed for the Levulan to be absorbed sufficiently. This incubation time may vary but typically is between 1 to 2 hours (depending on location on body being treated, severity of lesions, and patient’s sensitivity). Step 2 follows the incubation period when the patient is exposed to blue light or Blu U device. This Blu U device emits light in the blue wavelength of light. The Levulan is activated by blue light which results in destruction of the abnormal cells, i.e. actinic keratosis. Typically patients are exposed to the light for 1000 seconds or a little more the 16 minutes. During Blu U light exposure patients will feel pain or burning sensation in the treated areas; the severity of which may range from mild to severe. Although uncomfortable the discomfort is manageable. A cooling fan with cool water applications helps alleviate some of the discomfort during the treatment. The discomfort tends to be worst for the first few minutes and then tends to lessen as the treatment under the light continues. However for the next 2 days (48 hours), the treated area will remain very photosensitive (light sensitive) so that exposure to sun or very bright light will cause more burning and stinging. During this time patients are encouraged to stay indoors during the daytime.
After the blue light treatment, the treatment area will typically be more red, sunburn appearing. Besides redness many of the spots will get crusty. The redness begins to fade after one week at which point, like a sunburn, peeling will be noticed. By 2 weeks the skin most patients are noticing much smoother skin. Overall, for patients with multiple actinic keratosis on the face, PDT offers the highest clearance rate of actinic keratosis. Additionally, a nice side effect of PDT is that most patients see improved texture and appearance, in which the skin appears rejuvenated and more youthful.