Psoriasis - Phototherapy

Broadband Ultraviolet B (UVB) Radiation

Broad spectrum UVB is radiation measured at 290 to 350 nm and has been the standard UVB phototherapy treatment in US. It may be administered with or without medications. When used without medication (known as selective ultraviolet phototherapy), UVB treatment generally is administered as follows:

Treatment is typically first administered in the doctor's office or another medical setting. Once the disease has stabilized, the patient can obtain a prescription for equipment that can be used at home. Even at home, treatment must always be supervised, however.
In preparation, the patient fully undresses, although unaffected areas may be covered to avoid overexposure.
The initial session may last as little as a few seconds, depending on whether the patient has a lighter or darker skin, with the lightest skin exposed to the briefest session. The duration increases with each treatment until the skin clears or the patient experiences itching or irritation. (It should be noted that the condition may worsen initially.)
UVB therapy usually requires about 20 to 40 treatments (about three per week). Full results take about three weeks.
Patients should avoid natural sunlight on treatment days, since they risk becoming seriously sunburned at these times.
Maintenance treatment is sometimes required--usually twice weekly for one to two months and then once a week for about four months. This is generally effective in preventing relapse. Individuals vary, however, in their response.

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Use of Medication. UVB was commonly used with coal tar (the Goeckerman regimen) in past decades and then with anthralin (the Ingram regimen). Other medications are being investigated with some success and may prove to be more tolerable.

The Goeckerman regimen requires daily treatments for up to four weeks. The coal tar or anthralin are applied once or twice each day and then washed off before the procedure. Studies indicate that a low-dose (1%) coal tar preparation is as effective as high-dose (6%). Such regimens are unpleasant, but still useful for some patients with severe psoriasis, since they can achieve long-term remission (up to six to 12 months).

Some evidence suggests that by using a simple emollient (e.g., Vaseline, mineral oil) that enhanced UVB light penetration can be effective. (This increases the risk for sunburning, however, and care must be taken.)

Combinations of other topical and oral medications are being tried. For example, combining UVB with methotrexate or retinoids, such as a tazarotene gel or oral acitretin, is producing positive results. Combinations with any of these agents, however, must be supervised carefully to avoid adverse reactions.