Does light therapy (phototherapy) help reduce psoriasis symptoms?

UV light therapy approaches such as UVB phototherapy and psoralen plus ultraviolet A (PUVA) can effectively reduce psoriasis symptoms. But the treatment involves quite a lot of effort because you need several sessions per week. Repeated and long-term light therapy can also increase the risk of skin cancer.
Psoriasis can often be effectively treated with a good skincare routine and medication applied to the affected areas of skin. But this doesn’t always help enough in moderate and severe psoriasis. UV light therapy is then considered. This treatment, also known as phototherapy, can be used on its own or in combination with topical (externally applied) medication or tablets. It involves exposing the affected areas of skin to ultraviolet light (UV light). UV light reduces inflammation and slows the production of skin cells.
The treatment is usually given three times a week in a dermatology practice or hospital. It takes place in special cabins with fluorescent lamps that emit UV light of a certain wavelength. There are also lamps that can be used to treat individual parts of your body, such as your head, hands or feet.
Tanning beds can't be used for light therapy because they don’t allow you to control the exact spectrum and dose of light you are exposed to.