UVB Phototherapy
This form of phototherapy relies on a specific wavelength of UV light known as UVB. This can be given as broadband UVB or narrowband UVB (narrowband uses a narrower range of light wavelengths than broadband UVB). Unlike PUVA, UVB therapy can be given on its own as it is absorbed mainly by the upper layer of skin and so does not need a chemical to sensitise the skin to its effects. However, it may also be combined with other topical or systemic treatments for psoriasis which allows for a reduced exposure to UVB.
How does it work?
UVB phototherapy prevents the rapid replacement of skin cells which can otherwise lead to patches of psoriasis.
When is it used?
Your healthcare team may recommend UVB therapy if you have moderate psoriasis.
How is it administered?
You will be given protective equipment before your UVB therapy. This will protect more delicate areas of your body, such as your eyes. You will be asked to lie under or stand next to a UV light source. The phototherapy booth often looks like a sun bed.
Your healthcare team will have decided on how much UVB you need (the strength of the UVB light, and the length of exposure to it) based on the severity and type of your psoriasis. UVB therapy is normally administered 2–3 times a week until your psoriasis improves. This may then be reduced.
Advantages and disadvantages
UVB therapy can be an effective treatment. It combines well with topical or systemic treatments because it works in a different way and side effects are uncommon. There is still presumed to be a risk of skin cancer with UVB therapy, but the evidence available suggests it is less of a risk than PUVA.
With UVB therapy, there is a slight risk of burns to the skin (similar to sunburn) and of premature ageing of the skin. This is due to the effect of the UV light on your skin, and is the same as the effects of too much exposure to direct sunlight.
If you have any questions about UVB, you may want to discuss them with a member of your healthcare team.