Narrowband UVB phototherapy

Narrowband UVB is now the most common form of phototherapy used to treat skin diseases (2008). Narrow-band refers to a specific wavelength of ultraviolet (UV) radiation, 311 to 312 nm. UVB phototherapy was formerly provided as a broadband source (290 to 320 nm).

This range of UV radiation has proved to be the most beneficial component of natural sunlight for psoriasis. Narrowband UVB may also be used in the treatment of many other skin conditions including atopic eczema, vitiligo, pruritus, lichen planus, polymorphous light eruption, early cutaneous T-cell lymphoma and dermographism.

Compared with broadband UVB:

• Exposure times are shorter but of higher intensity.
• The course of treatment is shorter.
• It is more likely to clear the skin condition.
• Longer periods of remission occur before it reappears.

Side effects

Narrow-band UVB can result in burning, just like sunlight and broadband UVB. Frequent emollients should be applied to burned skin, and if recommended by the therapist, topical steroids. It sometimes provokes polymorphous light eruption.

Long term exposure to ultraviolet radiation ultimately causes skin ageing and skin cancers. Although the risk from narrow-band UVB is unknown, research to date suggests it is no more risky than broadband UVB and probably less risky than photochemotherapy (PUVA).

Blistering due to UVB

What does the treatment involve?

Patients attend two to five times weekly. The patient is placed in a specially designed cabinet containing fluorescent light tubes.

The patient stands in the centre of the cabinet, undressed except for underwear, and wears protective goggles. Usually the whole body is exposed to the UVB for a short time (seconds to minutes).

The amount of UV is carefully monitored. A number of protocols exist depending on the individual's skin type, age, skin condition and other factors.

The skin may remain pale or turn slightly pink (the Minimal Erythemal Dose) after each treatment. Let your therapist know if you experience any discomfort.

Patches of psoriasis generally start to become thinner after five to ten treatments. Most patients with psoriasis require 15 to 25 treatments to clear.