Phototherapy for psoriasis

Psoriasis is a chronic recurring disease. It is generally accepted that it is almost impossible to cure it - at best, the disease is transferred to a stable period of attenuation of the process. Specialists offer more and more new methods of treating psoriasis, and many of them really help to "forget" about unpleasant symptoms for a long time. Such methods include phototherapy, or light therapy - irradiation of the skin with ultraviolet rays. Phototherapy for psoriasis is used very often, although the irradiation procedure can also be used in relation to other dermatological pathologies.

Effectiveness of phototherapy in psoriasis

The effectiveness of phototherapy for psoriasis depends on how deeply the ultraviolet rays penetrate into the tissues. The most effective phototherapy is recognized as one that combines ultraviolet light irradiation and the use of long waves, with preliminary oral administration of photosensitizing drugs.

Phototherapy may involve the use of different rays:

• Narrowband UVB treatment targets the epidermal layer;
• UVA radiation penetrates deeper into skin tissue.

The therapeutic effect of ultraviolet radiation is due to their intervention in the processes of synthesis of tissue hormonal substances - the so-called cytokines, which have the property of immunosuppressors, that is, suppress the immune system. At the same time, under the influence of ultraviolet radiation, there is a renewal (transformation) of cellular structures, which helps to remove cells from the state of programmed cell death (apoptosis).

Advantages and disadvantages of phototherapy

Phototherapy for psoriasis is a procedure that has a number of undeniable advantages over other similar methods of treating psoriasis:

• Almost all patients tolerate the treatment well;
• the method is safe for medical professionals who are directly involved in the procedure;
• the results after phototherapy almost always meet expectations;
• With local use of phototherapy, the dosage of radiation can be precisely controlled, which allows minimizing the degree of carcinogenic hazard and general radiation exposure;
• With the general use of phototherapy, the appearance of psoriasis on healthy areas of the skin can be prevented.

But, as with any other method, phototherapy sometimes has side effects that you should know about in advance. Such manifestations can occur immediately after the procedure, or make themselves known months or even years later.

Among the early manifestations, the following can be distinguished:

• excessive dryness of the superficial layers of the skin;
• itching sensation;
• areas of hyperemia in the form of phototoxic erythema.

Late side effects are detected much later and may manifest as:

• photoaging of the skin;
• hyperpigmentation, skin spots;
• atypical skin degenerations (malignancies).

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Indications for the procedure

Phototherapy for psoriasis is prescribed mainly to establish a stable period of remission in the exudative and simple (classical) course of the disease - for example, in psoriasis of the head, palmar and plantar surfaces.

This method can be used for therapy in the presence of pustules and erythroderma, especially in complex cases. For the treatment of such patients, devices are used that are usually intended for local action.

As a photosensitizing substance, tablet preparations are taken: Ammifurin or Methoxsalen.

Selective phototherapy is prescribed to eliminate the symptoms of the classical and exudative psoriatic process - both in moderate manifestations of the disease and in the stage of increasing symptoms.

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Technique of phototherapy for psoriasis

Currently, medicine uses three phototherapy methods that are similar in technology for psoriasis:

1. photochemotherapeutic method, which is a combination of ultraviolet irradiation with oral administration of photosensitizing agents;
2. selective phototherapy, combining the use of long and medium waves;
3. Narrowband phototherapy, which is carried out using UVB irradiation with a maximum emission of narrow-wave rays of 311 nm.

• Photochemotherapy is considered the most effective, as a positive outcome after treatment is observed in 88% of cases. The treatment involves 3 to 4 sessions per week, with a total course duration of up to complete cleansing of the skin from psoriatic plaques. Usually, this may require 15 to 25 procedures. The initial radiation dose may vary in the range of 0.5-1 J per cm². Every second session is carried out with an increase in the dose of exposure by 0.5-1 J per cm². If the skin clears slowly, the doctor may decide to use local irradiation.
• Selective phototherapy for psoriasis is considered to be approximately 85% effective. Five sessions are performed per week with an initial dosage of 0.05-0.1 J per cm². The total duration of therapy is approximately 25 procedures.

It is characteristic that selective phototherapy for scalp psoriasis involves the use of a special UV comb, which allows for exposure even through the hair barrier. Such a comb can be used not only on the head, but also on the legs, chest, groin area and armpits.

• Narrowband phototherapy for psoriasis is close in effectiveness to photochemotherapy. This method causes complications such as burns, hyperemia, and malignant degeneration of the skin less often than others.

For therapy, specific lamps are used, which are produced exclusively by Philips. The lamps contain a special gas and are made of glass, which is capable of transmitting only light waves of a certain length.

This procedure can be performed locally and segmentally. Sessions are repeated 3 to 5 times a week with an initial dosage of 0.1 J per cm². If the response to treatment is good, then each subsequent session is performed with an increase in dosage by 0.1 or 0.2 J per cm². The total number of procedures is about 25.

Contraindications to the procedure

There are few absolute contraindications, in which phototherapy for psoriasis is absolutely impossible. These include the following cases:

• The presence of tuberculosis (phototherapy can sharply worsen the course of tuberculosis due to the sharp stimulation of metabolic processes).
• Diseases of the visual organs (during the procedure, phototoxicity may increase).
• Skin diseases accompanied by photosensitivity.
• Manic or hypomanic states that are present at the present time or have occurred previously.
• Background treatment with drugs that affect the photosensitivity of the skin.
• Porphyrin disease (porphyria).

Phototherapy may be used for psoriasis under strict medical supervision in the presence of hyperthyroidism, as well as during treatment with Methotrexate or Chloroquine.

Additional contraindications to the use of phototherapy include:

• malignant neoplasms;
• acute or chronic renal failure;
• severe liver pathologies;
• hypertension with a tendency to hypertensive crises;
• cardiac insufficiency;
• diabetes;
• severe atherosclerotic changes in blood vessels;
• stroke;
• increased risk of hemorrhages, blood clotting disorders;
• increased hair growth (hirsutism);
• dermatitis;
• systemic lupus erythematosus;
• acute period of malaria;
• hereditary or congenital hypertrophic photosensitivity of the skin;
• photodermatosis;
• collagenoses;
• excessive exhaustion of the body;
• cataract;
• mental disorders occurring against the background of increased nervous excitability.

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Consequences after the procedure

As we have already described above, phototherapy for psoriasis can be accompanied by a number of side effects - early and late.

Early manifestations include itching, dryness and redness of the skin at the sites of exposure.

Late symptoms may include actinic lesions and hyperpigmentation of the skin.

Photochemotherapy using photosensitizing drugs - psoralens - increases the risk of damage to the eye lens. Photosensitizing substances get inside it and under the influence of UV radiation create photoadditive metabolites with protein amino acids. Such metabolites are very tightly bound compounds that accumulate inside the lens during repeated photochemotherapy sessions, provoking the development of pathological changes. To avoid such negative consequences, it is recommended to use specially designed prophylactic glasses during the procedure and for 24 hours after it.

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Reviews of phototherapy for psoriasis

Phototherapy is a relatively new method in the treatment of psoriasis. Many patients note that the first few procedures can significantly slow down the growth of skin layers in the affected areas.

When irradiating, ultraviolet rays of different spectra are usually used: B and A.

When irradiating with ultraviolet B, the session continues until the skin becomes pinkish (about a minute). Gradually, the procedure time increases. When using such types of rays in the form of narrow-band irradiation, the risk of side effects is significantly lower than when using other types of phototherapy. As experts note, this is due to the fact that only the length of rays necessary for the treatment of psoriasis is used for the effect, and no more.

Ultraviolet A spectrum penetrates much deeper, and the session lasts longer. The frequency of side effects in this case increases significantly.

However, the greatest number of side effects are observed after the use of photochemotherapy, although this method is recognized as more effective.

Taking into account all the facts, patients increasingly choose narrow-band phototherapy for the treatment of psoriasis. Only this type of treatment can "boast" both the quality of treatment and the minimum set of side symptoms.

According to patient reviews, in order to completely clear the skin of psoriatic plaques, it is necessary to undergo approximately 20 phototherapy procedures. After that, twice a year you need to visit your doctor for observation and to exclude negative consequences of radiation.

Phototherapy for psoriasis has many positive and undesirable aspects. However, it should be taken into account that at present this method is one of the most effective and efficient for getting rid of this unpleasant disease.