Understanding Photodynamic Therapy (PDT) & Blue Light for Actinic Keratosis and Other Skin Conditions

With rising global rates of non-melanoma skin cancers linked to increasingly exposed skin to the sun, effective treatment options are in high demand. [1] Photodynamic Therapy (PDT) and Blue Light therapy have emerged as the latest treatment options in managing conditions such as Actinic Keratosis.

PDT uses photosensitizing agents and blue light, thus targeting the abnormal cells with a very high degree of selectivity. This article explores PDT and blue light therapy, describes mechanisms of action, applications in dermatology, and risks involved with these novel treatments.

What is Photodynamic Therapy?

Photodynamic therapy, or PDT, is a non-invasive medical treatment. It utilizes photosensitizing agents and light to find and destroy abnormal cells and tissues. This therapy has three essential components: a specific wavelength of light, a photosensitizing agent, and oxygen. [2]

PDT is widely used in dermatology to treat various skin conditions because it targets the involved sites well and is minimally invasive, with more acceptable cosmetic results compared with surgical procedures.

What is Photodynamic Therapy Used to Treat?

The treatment method is applied to a wide range of medical conditions, mainly related to dermatology and oncology. The following are some of the primary medical conditions treated with PDT:

• Actinic Keratosis: PDT effectively treats precancerous lesions caused by sun damage on the skin. [3]
• Basal Cell Carcinoma: PDT applies to superficial basal cell carcinoma.
• Acne: PDT reduces acne by targeting and destroying the bacteria that cause breakouts.
• Psoriasis: It reduces the symptoms of psoriasis because PDT slows down the rapid growth of skin cells and, therefore, reduces inflammation.
• Dermatological conditions: PDT is also used to treat different skin conditions such as warts, rosacea, and dermatitis.

How Does Photodynamic Therapy Work?

The Process of PDT

Photodynamic therapy destroys these abnormal cells through the following multi-step procedure, leaving the healthy tissue intact. All the steps of the process are looked at in detail in the following section:

Step 1: Application of Photosensitive Drug

The first step involved in PDT is applying the photosensitizing agent to the area to be treated. There are two significant photosensitizing agents in photodynamic therapy: Porfimer sodium, which is FDA-approved and is activated by red laser light, and Aminolevulinic acid, or ALA or Levulan, activated by blue light, which treats actinic keratosis and skin cancers. [4]

It can be in cream or gel form, but it can also be administered locally; this is why, sometimes, it is simply injected into the bloodstream directly. The photosensitizing drug has been designed to accumulate selectively in abnormally formed cells, at least to some degree. These cells are thus more predisposed to damage by light.

Step 2: Incubation Time

After photosensitizing drug administration, the drug requires an incubation time. Depending on the drug under use and the disease condition, it may vary from a few minutes to several hours.

As such, during the incubation time, target cells absorb this drug, while healthy cells are pretty much left out. Therefore, in this incubation period, the photosensitizing agent builds up to its maximum concentration inside the abnormal cell to make sure the process of light activation is as effective as possible.

Step 3: Light Activation

The final step of PDT is the exposure of light of an appropriate wavelength on the treated area, which is generally blue or red, depending upon the photosensitizing agent used. The light activates this drug, thus introducing and triggering a chemical reaction that generates a reactive form of oxygen. [5]

The reactive oxygen species thus generated are highly toxic to the abnormal cells and cause their destruction. The light can be delivered via lasers, depending on the situation, or LEDs, or other devices.

How Long Does PDT Take?

The photodynamic treatment usually takes between 15 and 90 minutes, depending on the size of the area to be treated. [6]

Which Types of Skin Cancer is Photodynamic Therapy (PDT) Blue Light Used For?

PDT with blue light is used in the treatment of non-melanoma skin cancers such as the following:

• Actinic keratosis.
• Superficial basal cell carcinoma.
• Bowen’s disease (squamous cell carcinoma in situ).

What are the Possible Side Effects of Photodynamic Therapy?

Though PDT is generally well-tolerated, associated side effects include:

Common Side Effects

• Redness and Swelling
• Burning or Stinging
• Crusting and Peeling
• Sensitivity to Light

Less Common Side Effects

• Cough
• Blistering
• Trouble swallowing
• Stomach pain
• Infection

• Changes in Skin Pigmentation

Who is the Ideal Patient for Photodynamic Therapy and Blue Light Therapy?

The ideal patient for photodynamic therapy(PDT)  in dermatology is:

• Chronic Sun Damage and Pre-Cancers: Ideal for extensive sun damage and multiple actinic keratosis lesions without scarring risk.
• Acne Vulgaris: This is helpful for antibiotic-resistant acne. It improves both the active lesions and scars with ALA-PDT.
• Superficial Skin Cancers: Treat basal cell carcinoma or Bowen’s disease in sensitive areas with cosmetic concerns.
• Comprehensive Skin Rejuvenation: Targets actinic keratosis and rejuvenates sun-damaged skin for a smoother complexion.
• Non-Invasive Option: It has minimal downtime and less risk for scarring compared to surgical treatments, which makes it a very appealing therapy for those in comprehensive skin care.

Does Photodynamic Therapy Treat Cancer?

Photodynamic therapy and blue light therapy effectively treat actinic keratoses and some skin cancers, such as basal cell and squamous cell carcinomas. Initially FDA-approved for skin cancer, PDT targets and destroys abnormal cells using activated oxygen molecules, sparing healthy skin. [7]

In the beginning, PDT was used only for the face and scalp; today, it is used to treat the neck, chest, arms, legs, and trunk. The treatment usually requires three sessions at intervals of four weeks apart but can be modified according to the severity of the lesion.

How Does Photodynamic Therapy Improve Acne?

Photodynamic therapy is effective in the treatment of various types of acne by shrinking oil glands, reducing sebum production, and unclogging pores. ALA-PDT (5-aminolevulinic acid with PDT) is ideal for patients who cannot use isotretinoin. It kills the acne-causing bacteria and improves skin texture. [8]

Treatment involves microdermabrasion, applying Levulan for 20 to 60 minutes, and blue light therapy for about 15 to 20 minutes. Three to five sessions are typically needed, spaced four weeks apart, with noticeable improvement after one session.

What is Blue Light Photodynamic Therapy?

Photodynamic therapy with blue light is a non-invasive treatment that selects abnormal skin cells for destruction by administering a photosensitizing agent and then applying the blue fluorescent light. Very effective for treating actinic keratoses, among other conditions, it offers little downtime and can even treat large areas of damaged skin at one time.

PDT/ Blue Light for Actinic Keratoses

Years of sun exposure give people scaly patches of rough skin, sometimes cancerous but more often just sunspots, most commonly found on the face, scalp, hands, and forearms. A combination of blue light and a particular photosensitizing medicine targets those pre-cancerous cells and then stops their growth by depriving them of oxygen. [9]

There are three steps to the effective treatment:

1. Application: This light-responsive medical solution is applied to the affected part.
2. Light Exposure: Following an incubation period to allow the medication time to be absorbed into the skin, which can range from 2-48 hours, depending upon the medication, the skin is exposed to a special blue light.
3. Post-Treatment Care: The treated area is then moisturized and covered with zinc oxide sunscreen.

This relatively simple process makes it an excellent procedure to remove pre-cancerous skin lesions and avoid one’s skin cancers.

How Can I Prepare for My AlA-PDT and Blue Light Treatment?

• Consultation: Talk to your dermatologist about your medical history, medications, and allergies.
• Avoid Sun Exposure: Avoid exposure to the sun and tanning beds for at least two weeks before.
• Discontinue Certain Medications: Such may include photosensitizing medications and topical products.
• Clean Skin: Your skin must be free of makeup, lotions, or other products on treatment day.
• Protective Measures: Wear a wide-brimmed hat and protective clothing after treatment.
• Transportation: Arrange for someone to drive you home if needed.
• Comfortable Clothing: Wear loose, comfortable clothing to help avoid irritation to treated areas.

What to Expect Following Photodynamic and Blue Light Therapy

After Photodynamic Therapy, temporary side effects include redness, swelling, and a sensation of burning similar to that of mild sunburn. [10] These are anticipated effects of the treatment in practical action.

You will be very sensitive to light for approximately 48 hours of treatment. Thus, avoid direct sunlight protective clothing and broad-spectrum sunscreen in case you need to go out. Best of all, it has minimal downtime and is an outpatient procedure so you can return home immediately after the treatment.

In the long term, you can expect improved skin appearance, reduced lesions, and minimal scarring, with a lowered risk of skin cancer.

What Should I Avoid After PDT and Blue Light Therapy?

After PDT and Blue Light Therapy, you should avoid:

• Sun and UV Exposure: Avoid sunlight and UV exposure for 48 hours post-treatment to prevent skin damage and increased sensitivity.
• Avoid Scrubbing: Refrain from picking or scrubbing the skin to prevent scarring or infection.
• Saunas and Steam Rooms: Avoid heat exposure, including saunas and steam rooms, to prevent skin irritation.
• Bright Lights: Avoid bright indoor lights and reflective surfaces due to increased light sensitivity.
• Exfoliating Products: Avoid using exfoliating skincare products such as retinoids or alpha hydroxy acids.

What Is the Recovery Time After Photodynamic Therapy?

PDT is a minimally invasive outpatient procedure. It involves almost no downtime. The significant and expected side effects include redness, itchiness, and swelling seen during the treatment, which resolves within 2-3 days. It is recommended to avoid exposure to UV light for 24 hours because the skin becomes sensitive after the therapy.

The Bottom Line

PDT with blue light is a highly effective, minimally invasive treatment for many skin conditions, most of all actinic keratoses and some non-melanoma skin cancers. Since the treatment has minimal downtime and is an outpatient procedure, the patients usually appreciate it.

Furthermore, PDT provides overall skin rejuvenation and is, therefore, one of the best treatments to go for when good results with minimal side effects are achieved. At UVTreat, our professionals can help guide you through the process—fill out our form today to begin your journey towards healthier skin.