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Photodynamic Therapy, PDT
PDT is an established modern technique where a topical dilute specific acid application to the skin induces a tissue biochemical activation, followed by a laser treatment. This can achieve dramatic clearance of sunspots and many skin cancers, controls acne or rosacea, and rejuvenates the skin. It can be helpful in treating psoriasis and warts. Treatments are usually repeated 4 weeks later. Large areas or just localised lesions may be selected for PDT.
Before The Procedure
A diagnostic skin assessment is performed to exclude other skin cancers, and baseline photographs are taken. Topical preparatory skincare is prescribed for up to 4 weeks before PDT, desirable for more rapid healing. UV screens, Vitamin A, and alphahydroxy acids and moisturizers are recommended. Topical Vitamin C also helps with rosacea and more Celtic skins. Darker skin types may need pre-treatment with a pigment reducing cream at night as well to prevent an unwanted pigmentary response.
On The Day
Please arrive with no head or neck jewellery, and no skin applications or makeup. The areas to be treated will be prepared for treatment by cleansing and dermabrading, then a dilute photosensitizing acid is applied with a brush (alphalaevulinic acid). This is not painful, with a warm slight stinging sensation. A time interval for absorption and a biochemical change in the tissues is required. This creates a target for the ensuing laser activation. You will need to attend for 3-4 hours. Initial preparation takes 15- 30 minutes, a time delay for incubation of 30 minutes to 3 hours, and laser light activation takes 20-40 minutes.
Some redness and swelling is usual. We reduce this immediately post-treatment using ice and topical LED light therapy. Redness will be further reduced by rest, but it still may last for hours or days. Strict sun avoidance for 48 hours is important - the sun will continue to act as a laser initially, causing crusting. Applying moisturisers frequently is helpful and we supply patients with a post-laser treatment cream specifically formulated to help the skin return to normal as quickly as possible. Slight peeling can occur 3-4 days later. Age spots may darken for a few days. Results of treatment improve over 3-4 weeks. A freshened rejuvenated skin appearance usually results.
Control of inflammatory acne is the initial goal, in combination with appropriate topical therapy. The process destroys the active bacteria (Propionebacterium acne), and overabundant pilosebaceous units. This is an alternative to oral Roaccutane (Isotretinoin). Acne scarring can be treated with a CO2 laser, needle rollering, dermabrasion, or chemical peels.
Actinic or solar keratoses (AKs) are common after UV exposure, and are pre-malignant. Found in sun exposed areas, they can be scaly, pigmented or flat. 10-15% will progress to some form of skin cancer. Individual lesions can be treated. Treating whole areas as a “preemptive strike” clears existing AKs as well as new ones which may be forming but are not yet visible.
PDT is a suitable treatment option for non-melanoma cancer, most basal cell cancers (BCCs) , and selected superficial squamous cell cancers (SCCs or Bowens disease). It is an alternative to surgery, localised cryotherapy, or months of topical Aldara or Efudix treatment. Cryotherapy often causes permanent white scars, and just treats local areas of skin. Many cancers on the face can be removed by PDT as effectively as surgery, without needles or scarring. Lesions become irritated and red for 7-10 days post PDT, slowly resolving. Further PDT treatment may be needed for clearance and is easily repeatable if required.
This is characterised by fine red facial veins that may flush or blush with exercise, alcohol or some foods. Rosacea is familial and also caused by sun exposure. An acne-like lumpy rash on the nose and cheeks can be associated. Treatment may involve good UV screens and sun avoidance, oral antibiotics, topical Rozex, and Vitamin C. Unwanted red veins are coagulated and removed with a vascular laser. PDT is a great treatment for rosacea.
Common areas treated with PDT are the face, neck, décolletage, hands, forearms, and occasionally the scalp, legs and shoulders.
Who Should be Treated?
PDT would be deferred if you have had a recent sunburn, with recent or current Roaccutane use, during pregnancy or lactation, if you are medically unwell, or if you have active cold sores or a skin infection. It is contraindicated with known photosensitive skin, such as porphyria.