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The application of UVB light is administered under the observation of a doctor, and is used both on of the extensive and in the localized sections of psoriasis. UVB is used when local topical drug treatments were not successful enough, or in a combination with the topical drug treatment.
Short-term risks during the application of UVB are minimal. Long-term risks are the same as with the chronic effect of solar radiation: cancer of the skin and aging of the skin. However, the prolonged studies, carried out on the large number of patients, who obtained UVB psoriasis treatment, did not show an increase in the development of t skin cancers, so this type of treatment can be safer than solar irradiation. UVB treatment is estimated to be one of the most effective and safest types of psoriasis therapy.
Some people with psoriasis purchase domestic UVB lamps and perform UVB sessions themselves. During the independent application of this procedure it is highly recommended to consult with a doctor periodically.
UVB light is divided into 3 parts:
- Broadband UVB (280-320 nm),
- Selective Broadband UVB aka SUP (305-325 nm),
- Narrowband UVB aka NB UVB(~311 nm).
Narrowband UVB is statistically the most effective in psoriasis treatment, so let's discuss it in more detail. The lamps of this spectrum have a maximum emission of 311-313 nm. It is considered that this emission is the most "valuable" for psoriasis from the entire UV spectrum range.
There is noted a high efficiency in the application of an ultraviolet light of precisely this range, smaller quantity of procedures, necessary for achievement of a positive effect, shortening of the exposure time due to an increase in the dosage, larger periods of remission, considerably smaller side-effects, the possibility of combination of this therapy with other types of psoriasis treatment. The carcinogenicity of this type of psoriasis treatment is the smallest compared with the remaining types of UV light.
There are several protocols for the application of NB-UVB. Usually 3-4 procedures a week are administered. The irradiation is conducted in a special compartment - on the localized zones or on the whole body with the disseminated type of psoriasis. The time of the procedure comprises from several seconds to several minutes.
Treatment begins with the determination of a MED (Minimal Erythemal Dose (erythema - abnormal reddening of skin)) of healthy skin, this is the border between the reddening of the skin and any signs of the burns of the first degree (similar to a sun burn) in a period of 24 hours. MED is necessary to determine for the establishment of a maximal UVB irradiation dose. MED depends on the skin type and some other factors. There are special irradiation testers for the determination of the MED. There also is a MED calculation method according to the skin-type table.
The exposure time of the affected sections is increases by 10-20% with each UVB procedure and can reach 3 times MED and even more in some occasions. Maximum UVB dose depends on the type of psoriasis, sight of psoriasis on the body and the skin reaction during the course of treatment. The dose is gradually reduced after the start of the steady disappearance of the psoriatic plaques. Between the UVB procedures it is recommended to apply moistening creams on the skin of the body.
The decrease of the thickness of the psoriatic plaques, as well as, the decrease of their peeling is usually observed by the 5th-10th procedure, after which, a substantial improvement, including, the complete clearing of the skin from the psoriatic plaques by the 15th-30th procedure.
Maximum permissible quantity of the UVB is 40-45 procedures, after which it is necessary to have a month without any treatment.
After the completion of the UVB therapy it is sometimes recommended to undergo periodic supporting procedures (maintenance- approximately once a week).
In the case of thick psoriatic plaques some dermatologists prescribe hormonal ointments in order to remove the top layer of the plaques which will not let the UVB light penetrate the skin and therefore will not allow achieving the therapeutic effect in the locations of especially thick psoriatic plaques.
The dark pigmentation which remains from the psoriatic plaques and lesions after UVB disappears during a course of 1-2 months after the end of the procedures. The period of the remission statistically differs from about 4 to 10 months. Sometimes the remission after UVB can even last for years.
In the absence of any positive action with ultraviolet light alone, they then will use a combined therapy of procedures - for example with the use of Acitretin (synthetic derivative of vitamin A).
Erythema (abnormal reddening of skin) is the main side effect from the UVB therapy - it is a burn similar to a Sun burn. Small erythema rapidly disappears and is not dangerous, although it is uncomfortable due to a burning sensation and tightening of the skin. But the burns, which approach
2nd degree should be definitely avoided, as they may cause the development of new psoriatic plaques at the places of the burns.
Patients should use softening and moistening neutral creams a few hours after each UVB procedure.
Before the beginning of the procedure the patient should remove all creams, ointments, cosmetics etc. from the skin zones that will be irradiated with UVB.
Skin diseases not connected with psoriasis (Porphyria (usually hereditary abnormalities of porphyrin metabolism, often causing rashes brought on by exposure to sunlight), lupus (various chronic skin conditions characterized by ulcerative lesions that spread over the body) etc.) can be counter-indications for the UVB treatments and require a more in-depth consultation with a doctor.
If ultraviolet light penetrates into the eyes, it then may possibly develop into a Keratitis (eye inflammation) and Conjunctivitis (inflammation of the eye's outer membrane), therefore the use of UVB-protective goggles is compulsory.
In spite of carcinogenicity of the ultraviolet, there was not noted any substantial increase in the risk of the carcinoma of basal or squamous cells, nevertheless there exists data about an increase of risk of such carcinomas in the case of a large number of UVB procedures (more than 300) with the joint use of Tar medicines in comparison with the group of those that used treatment of the NB-UVB alone in the moderate therapeutic doses. In this case, if the quantity of procedures exceeds the indicated number, you should consult with your doctor and have a further in-depth examination of your skin.
It is a good idea for a person with psoriasis to try to undergo a course of UVB procedures, whether at home or in a medical center. The UVB lamps that cover the whole body for home use are usually pretty expensive, but there also are smaller lamps for local applications - face, single plaques, brushes for scalp etc. So it is possible to treat the whole body in a medical center and to purchase a small UVB brush for the treatment of singular psoriasis spots.
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