PUVA therapy for psoriasis
PUVA therapy for psoriasis is a physiotherapeutic method of treatment using a photoactive drug against the background of irradiation of the affected skin with ultraviolet light. This technique was developed back in the last century and has been successfully used by American and European scientists since 1978 for the treatment of psoriasis and other skin pathologies. According to the available data, treatment success is achieved on average in 85% of cases.
Content:
- How does PUVA therapy work for psoriasis?
- Types of PUVA therapy for psoriasis
- How is the PUVA therapy procedure for psoriasis?
- Indications for PUVA therapy for psoriasis
- Contraindications to PUVA therapy for psoriasis
- Side effects of PUVA therapy for psoriasis
How does PUVA therapy work for psoriasis?
Psoriasis or lichen scaly is a chronic skin condition that is not contagious, although it is widespread throughout the world. Psoralens, when applied to the skin or after ingestion, do not have a therapeutic effect on their own. They begin to work only after ultraviolet light hits the dermis.
Psoralens bind to epidermal DNA and begin to inhibit the activity of certain molecules. However, the natural functions of skin cells are not affected.
1.5 hours after irradiation, reactions are triggered in the skin, the result of which is the creation of cross-linking "DNA-photosensitizer". They, in turn, have the following effects:
- Prevents the occurrence of pathological skin keratinization processes;
- It has a detrimental effect on pathologically active keratocytes and lymphocytes;
- Stimulates the production of active oxygen;
- They start the metabolic processes of arachidonic acid;
- Reduces the level of DNA synthesis of the epidermis without affecting its natural functions.
Ultraviolet radiation is widely used in the treatment of psoriasis. It has antibacterial, immunomodulatory and anti-inflammatory effects. The application of psoralens to the skin increases the efficiency of the irradiation several times.
Types of PUVA therapy for psoriasis
PUVA therapy for psoriasis can be implemented in three ways:
- Systemic therapy. The patient needs to take drugs in pill form. Psoralens are taken 2 hours before the start of the irradiation procedure. This method of treatment is the most widespread.
- Local therapy. The patient applies psoralens to the skin. They can be applied in the form of ointments, emulsions or creams. The irradiation procedure begins immediately after the application of the drug.
- Taking therapeutic baths. The patient takes a bath in which one or another photosensitizing drug is dissolved.
Types of psoralens. Psoralens can be of two types - natural preparations obtained from plants and synthetic, which are a product of chemical origin.
Natural psoralens are obtained by the extraction method. The drugs in this group are: Methoxalen and Ammifurin.
Synthetic psoralens are most commonly used to treat vitiligo rather than psoriasis. The drug in this group is Trimethylpsoralen.
Both synthetic and natural psoralens can be ingested and used externally. Calculation of the dose of the drug for oral administration: 0.6-0.8 g / kg body weight.
How is the PUVA therapy procedure for psoriasis?
PUVA therapy can be carried out in a polyclinic, in specialized medical institutions, in dispensaries. The drugs are taken orally, washed down with milk or eating low-fat food. After 2-3.5 hours, the patient is exposed to ultraviolet radiation. An irradiation session lasts several minutes. Each subsequent procedure is longer in time.
Depending on the patient's condition, a general effect on the whole body or local irradiation is possible. The dose is calculated based on the patient's skin type.
For the first time, a small area of the dermis (no more than 2 cm) should be exposed to ultraviolet rays. After 2-3 days, the results of the procedure are evaluated. The initial dose is 0.5 to 3 J / cm 2.
After carrying out PUVA therapy while taking psoralens, a person will need to protect their eyes from the sun with glasses for 24 hours. This is necessary for the prevention of cataracts.
For patients with psoriasis, topical application of psoralens is most often recommended. As practice shows, it is the local impact on the lesion focus that allows you to achieve the best results.
As for the frequency and number of procedures, they are determined depending on the individual condition of the patient. A full course can consist of 10-30 procedures. The break between procedures is one day. In the future, it is possible to carry out maintenance therapy, or a gradual decrease in the radiation dose with the rejection of the PUVA technique.
Indications for PUVA therapy for psoriasis
With the help of PUVA therapy, all forms of psoriasis can be treated, provided that the lesions affect 20-30% of the body or more. Prescribe ultraviolet irradiation with the use of psoralens for pustular, plaque, punctate and palmar-plantar psoriasis. Therapy can be used for erythrodermic and exudative psoriasis.
PUVA therapy is recommended when medical or other physiotherapeutic treatment does not give the desired effect. The technique can be used even against the background of a progressive disease, however, it is first necessary to carry out therapy aimed at removing intoxication from the body.
Contraindications to PUVA therapy for psoriasis
Do not prescribe PUVA therapy for the following conditions:
- Hypersensitivity to psoralens.
- Diseases such as: systemic lupus erythematosus, albinism, porphyria, pigmented xeroderma.
- Melanoma.
- Carrying a baby.
- Afakia.
Care should be taken to prescribe PUVA-therapy procedures to fair-skinned patients, patients with impaired immunity, against the background of identified malignant tumors and other oncological diseases. Patients with cataracts and renal failure should be under special supervision.
Side effects of PUVA therapy for psoriasis
If psoralens are used orally, there is a risk of developing the following side effects:
- Nausea and vomiting;
- Decreased appetite;
- Stomach ache;
- Allergy accompanied by itchy skin;
- Headaches, insomnia, dizziness, depression;
- Drop in blood pressure.
With external use of drugs, it is possible to increase the dryness of the skin, increase itching, and develop dermatitis. However, such reactions are most often the result of an incorrect procedure. Without fail, all patients who have undergone PUVA therapy should be observed by an ophthalmologist over the next 12 months.
The author of the article: Kuzmina Vera Valerievna | Endocrinologist, nutritionist
Education: Diploma of the Russian State Medical University named after NI Pirogov with a degree in General Medicine (2004). Residency at Moscow State University of Medicine and Dentistry, diploma in Endocrinology (2006).
