Exposure to UVA light is the treatment used to treat psoriasis. It is not possible to cure psoriasis but it can be kept under control by using the ultraviolet radiation method. In this method the psoriasis affected person is subjected to ultraviolet rays either from the sun or by artificial source.

The UV rays will kill the T cells which are the main cause behind psoriasis because immune system disorder is also one cause for psoriasis. The person has to get into a box whose size is equal to that of the telephone booth size. The lamp present in the box emits UV light on the person which slows down the rate of skin cell division resulting in reduced rate of psoriasis. This treatment has to be taken three to five times a week.