What is UVB and how does it work?
UVB and UVA are types of ultraviolet radiation.Present in natural sunlight, ultraviolet light B (UVB) is an effective treatment for psoriasis. UVB penetrates the skin and slows the rapid growth of skin cells associated with psoriasis. Treatment involves exposing the skin to an artificial UVB light source for a set length of time on a regular schedule. There are two types of UVB treatment, broad band and narrow band.
Narrow-band UVB is similar to broadband UVB in many ways and is becoming more widely used. Several studies indicate that narrow-band UVB clears psoriasis faster and produces longer remissions than broadband UVB. It also may be effective with fewer treatments per week than broad-band UVB.
Who is a candidate for UVB?
Both adults and children can benefit from UVB treatment. It is effective in treating psoriasis for at least two-thirds of patients who meet these conditions:
Thin plaques (minimal scale buildup)
Moderate to severe disease (involving more than 3 percent of the skin)
Responsive to natural sunlight (most people are)
A treatment program may include medicines applied to the skin or taken by mouth, as well as UVB. Topical medicines, such as anthralin, coal tar, calcipotriene (brand name Dovonex) and tazarotene (brand name Tazorac) are effective along with UVB in some people. Using systemic drugs such as methotrexate, biologics and acitretin (brand name Soriatane) with UVB may also improve the effectiveness of the treatment.
How is UVB administered?
Usually, the patient undresses to expose all affected areas to the ultraviolet light. He or she then stands in a treatment booth lined with UVB lamps. A person will generally receive treatments three times per week. It takes an average of 30 treatments to reach maximum improvement of psoriasis lesions. The first exposure to the light is usually quite short, lasting as little as a few seconds. Exposure time depends on the person's skin type and the intensity of the light emitted from the bulbs.
Since people with lighter skin absorb more light (and sunburn more easily), they start with shorter exposure times than people with darker skin. If there is no itching and/ or tenderness from the previous session, the next treatment will be longer. Administering UVB light is not an exact science. Each person's reaction to the light is not completely predictable.
UVB requires a significant time commitment. Individuals get the best results when they receive the regular follow-up treatments and strictly adhere to the action plan they make with their doctor.
What happens once the skin clears?
Once the skin clears, phototherapy may be stopped. Individuals may resume phototherapy to maintain skin clarity as the lesions begin to reappear.
However, studies show that continued UVB treatments after the skin clears can increase remission time. Most people need about eight maintenance treatments per month to prolong periods of skin clarity. However, it is different for every person.
If psoriasis lesions return, an individual may return to three treatments per week. Sometimes rotating different psoriasis treatments can give the skin a break from UVB. This minimizes longterm exposure and possible side effects.
For More Information, please visit the National Psoriasis Foundation.