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Broad spectrum or broadband UVB is radiation in the wavelength of 290 - 350 nanometers, and is the standard UVB phototherapy treatment in the United States. It is not as potent as the treatments that use narrowband UVB or PUVA, and is not useful for chronic psoriasis.
Broadband UVB may be given with or without medications. When used without medication (known as selective ultraviolet phototherapy), UVB treatment is generally given as follows:
- Treatment starts in the doctor's office or another medical setting. Once the disease has stabilized, the patient can get a prescription for equipment that can be used at home. Research finds that home UVB treatment is just as safe and effective as hospital-based treatment, and patients may be more likely to get the treatments they need if they administer them at home. Even at home, treatment must always be supervised.
- In preparation, the patient fully undresses, although unaffected areas may be covered to avoid overexposure.
- The initial session may last for just a few seconds, depending on whether the patient has lighter or darker skin. The lightest skin is exposed to the briefest session. The duration increases with each treatment until the skin clears or the patient experiences itching or irritation. The condition may worsen initially.
- UVB therapy usually requires about 20 - 40 treatments (about three per week). Full results take about 3 weeks.
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 studied with some success, and may prove to be better tolerated.
The Goeckerman regimen requires daily treatments for up to 4 weeks. The coal tar or anthralin is 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 a high-dose (6%) preparation. Such regimens are unpleasant, but are still useful for some patients with severe psoriasis, because they can achieve long-term remission (up to 6 - 12 months).
Some evidence suggests that using a simple emollient (such as Vaseline or mineral oil) that enhances UVB light penetration can be effective. This addition to the treatment increases the risk for sunburns, however, and patients must be careful to avoid sun exposure. Researchers are trying combinations of other topical and oral medications. 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 drugs, however, must be supervised carefully to avoid serious reactions.
Side Effects of UVB. The treatment can cause itching and redness. UVB radiation from sunlight is known to increase the risk for skin cancers. There is no strong evidence that UVB treatments pose any risk for skin cancers except on male genitals. This risk, however, can be significant (4.5%) at high doses.
Narrowband Ultraviolet B (NB-UVB) Radiation
Narrowband radiation may be safer than other approaches, and some scientists now believe it should be the first option for patients with chronic plaque psoriasis.
NB-UVB is used without medications and is very strong. Whether it has any effect on the disease process itself is unclear. The light wavelength is between 310 - 312 nanometers, which is the most beneficial part of sunlight.
Exposure times are shorter, but of higher intensity than with broadband UVB. This therapy is probably less likely than PUVA to cause skin cancers.
Clearance of 75% typically occurs after 10 - 12 treatments. NB-UVB treatments performed three times a week achieve results that are equal to twice-weekly PUVA treatments. Weekly NB-UVB treatments are not effective. Studies so far are mixed on whether NB-UVB remission rates are equal to those of PUVA.
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Review Date: 10/21/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School. Also reviewed by David Zieve, MD, MHA,
Medical Director, A.D.A.M., Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
