Psoriasis Ultraviolet Light Therapy

PUVA is an acronym for psoralen and UVA.

Psoralen is a light sensitizing agent.

In the presence of UVA, the psoralen combines with the cells in the skin to slow down their rate of reproduction. PUVA is usually used in adults with moderate to severe cases of plaque or guttate psoriasis or psoriasis of the palms or soles.

Nausea, itching, redness of skin. Higher risk of skin cancer. May be used alone or with steroids, UVB or some systemics.

Patient takes psoralen orally or it is applied to the skin. The patient then exposes the lesions to the UVA, typically standing in the lighting unit. The timing between taking the psoralen and entering the light box is critical. PUVA may be conducted 4 to 5 times a week, with the time of exposure increasing with each visit. Most people show some improvement after approximately one month and after two months, many are clear of psoriasis. Some patients may elect to continue once weekly maintenance therapy.

Expose lesions to an artificial UVB light source

UVB may be used when topical treatments have not been successful or there are numerous scattered patches of psoriasis. UVB slows the growth of skin cells. Can be used by adults and children.

May increase risk of skin cancer. This therapy may not be suitable for people who find it difficult to attend a treatment centre as frequently as required, or are not close to a treatment centre. May be used alone or with topical treatments or systemics.

Patient stands in a light box lined with UVB lamps, with affected areas exposed, for set amount of time. Sessions are usually 3 times per week for 10 weeks.