This type of phototherapy treatment consists of 2 components: psoralen and UVA light. When used alone, these two therapeutic elements are not as effective as their combination. Psoralens are naturally occurring compounds belonging to the furanocoumarin group of compounds. They increase the skin’s sensitivity to UV rays. One of the most widely used psoralens is methoxsalene. There are different forms of administration – ointments, tablets, injections. The type of PUVA therapy depends on the form of medicine chosen (see below). Psoralen is taken 2-4 hours before the planned UVA phototherapy. Psoralens are incorporated into the cell’s DNA chain and, when exposed to UVA light, become chemically active and initiate certain changes in the cell. Effects of PUVA therapy:
- Inhibits accelerated cell proliferation (i.e. cell proliferation).
- Inhibits angiogenesis (formation of new blood vessels).
- Promotes cell death.
- Immunomodulatory: alters the balance of inflammatory molecules, promoting inflammatory cell death.
- Stimulates melanogenesis (skin pigment production).
Types of PUVA therapy
Systemic PUVA: 1-2 hours before the scheduled procedure, a psoralen tablet is taken, the dose of which is chosen according to the patient’s weight. It is recommended to take the drug at least 1 hour after a meal. Nausea occurs in about 30% of patients, so the drug can be taken with certain foods, e.g. cheese, milk. Psoralen starts to act after 1 hour and reaches its peak of activity within 2-3 hours, after which its activity gradually decreases until it is finally eliminated from the body overnight. After a set period of time (usually 1.5-2 hours), the patient goes to the phototherapy booth and receives the necessary UVA treatment. The duration of the phototherapy (i.e. the time spent in the booth) is increased gradually. The treatments are carried out 2-4 times a week. It is recommended that the treatments be carried out no more frequently than every 48 hours. The treatment is continued until the rashes have visibly healed, gradually reducing the frequency of treatments. The most common course of treatment consists of 15-20 treatments, but each case is individual and further treatment tactics are discussed with the dermatologist. Dark sunglasses should be worn all day after the treatment, as the drug has a 24-hour effect on the body.
Wave PUVA therapy. This treatment is applied to the whole body as well as to localised areas (e.g. arms or legs only), and the required concentration of the solution is prepared accordingly. The bath is used for 15 to 20 minutes, followed immediately by the UVA treatment. The advantage of PUVA baths is that it is not necessary to wear dark glasses, the drug is not systemic and there is less chance of liver damage.
PUVA cream. Most commonly used in the presence of limited skin damage. It should be applied to the rash 1 hour before UVA phototherapy.
The advantages of PUVA, PUVA cream are that there is no systemic effect of the drug, so the procedure is safe for pregnant women. With topical PUVA therapy, psoralen disappears within 2-3 hours, and there is no need to wear dark sunglasses or apply additional UV protection.
Indications for PUVA therapy:
- Atopic dermatitis.
- Atopic dermatitis.
- Cutaneous lymphoma (fungal granuloma, mycosis fungoides).
- Severe eczema of the hands and feet.
- Vitiligo (whiteheads).
- Polymorphic sun rash (sun allergy).
These are the main diseases that can be successfully treated with PUVA therapy. However, this treatment method is also used for other, less common skin conditions. PUVA is decided on a case-by-case basis after consultation with a dermatologist.
Preparation for the procedure
- Assessment of the liver condition (i.e. certain blood tests).
- In some cases, an ophthalmologist’s consultation is also recommended.
It is important to find out about any medications the patient is taking. Some of them increase the skin’s sensitivity to UV rays and may interact with psoralen, increasing the likelihood of adverse reactions. Such drugs include diuretics of the thiazide group, tetracycline, certain painkillers, tar, etc.
Contraindications to PUVA therapy:
As with any medical intervention, PUVA therapy has certain limitations when it should not be used, such as:
- Pregnant and lactating women.
- Patients with lupus erythematosus, dermatomyositis, porphyria.
- Patients with xeroderma pigmentosum (a genetic disorder leading to extreme sensitivity to the sun’s UV rays, which leads to the development of malignant skin tumours as early as childhood).
- Severe liver or kidney damage.
- People with dysplastic (atypical) mole syndrome.
Adverse reactions are divided into 2 groups: acute, occurring during treatment, and remote, occurring after the end of treatment. The latter can occur even several years after phototherapy.
Acute adverse reactions:
- Skin redness, itching, pain.
- Redness and flaking of the skin all over the body.
- Increased skin pigmentation.
- Recurrence of blisters.
- Increased heart rate.
- Shortness of breath.
- Nail abnormalities.
- Swollen ankles.
Distant adverse reactions:
- Actinic keratoses (precancerous skin disease).
- Squamous cell carcinoma.
- Increased hairiness.
- Premature skin ageing.
- Slags in the skin.
Course of treatment
The UVA dose is selected according to the patient’s skin phototype or minimum phototoxic dose (MFD). Determination of the MFD: the inner surface of the forearm or the lower back is exposed to UVA starting from 0.5 mJ/cm2 to 5 mJ/cm2. A total of 6 skin areas of 1cm2 are exposed. The evaluation shall be done after 48-72 hours, when the psoralen effect will have peaked. The MFD is defined as the lowest dose of UVA radiation that results in homogeneous, well-defined reddening over the entire area of UVA exposure. Treatment shall be initiated at 50-70% of the MFD dose rate.
- Protective goggles shall be worn during the treatment.
- The genitals are covered.
- The face and unaffected areas shall be lubricated with sunscreen.
- After the procedure, tinted glasses must be worn throughout the day.
- During and after the PUVA course, it is recommended to visit a dermatologist regularly (at least once a year) for a check-up to assess moles and other skin lesions.
- Regular ophthalmologist consultation for the development of cataracts.
The Laser Dermatology Centre uses the state-of-the-art Waldman® phototherapy system.
This type of treatment is available at our centres in Vilnius and Klaipėda.
Patients who have already undergone phototherapy (whether in our centre or not) are entitled to a reduced price.