Psoriasis Treatment: UVA Beats UVB

(WebMD)  PUVA, an older treatment that uses ultraviolet A light (UVA), works better than a safer, more convenient one using UVB, or ultraviolet B light, in clearing psoriasis outbreaks.

By itself, ultraviolet A light doesn't do much for psoriasis.

That's where the "P" in PUVA comes in. It stands for psoralen, an oral drug that makes the skin much more light sensitive. PUVA is a tried and true phototherapy treatment for chronic plaque psoriasis.

But it takes about 16 to 19 PUVA treatments to put a psoriasis outbreak into remission. Therein lies the risk. After 160 to 200 lifetime treatments, there is a chance PUVA will cause non-melanoma skin cancer.

Dermatologists hoped a safer treatment — using narrowband ultraviolet B (NB-UVB) light — would fight psoriasis as well as PUVA.

But in a head-to-head test on 93 patients with plaque psoriasis, a British study now shows PUVA is better.

"Compared with NB-UVB, PUVA achieves clearance in more patients, with fewer treatment sessions, and results in longer remissions," reports Sami S. Yones, MSc, and colleagues at King's College in London, England.

For the four most sensitive skin types (basically, anything other than the type found among blacks or in darker-skinned Mediterraneans or Hispanics):

PUVA cleared up psoriasis in 84 percent of patients, vs. a 65 percent clearance rate for NB-UVB.

On average, it took 17 PUVA treatments to clear psoriasis, vs. 28.5 NB-UVB treatments.

For most patients, remission after PUVA lasted eight months, while remission after NB-UVB lasted only four months.

The researchers note their findings closely match those from three previous studies of PUVA and NB-UVB.

"Our results suggest that PUVA, compared with NB-UVB, tends to clear psoriasis more reliably, with fewer treatments, and for longer," Yones and colleagues conclude. "[PUVA] should therefore still be used in appropriate patients."

The findings appear in the July issue of Archives of Dermatology.


SOURCES: Yones, S.S. Archives of Dermatology, July 2006; Vol. 142: pp. 836-842.

By Daniel J. DeNoon
Reviewed by Louise Chang, M.D.
© 2006, WebMD Inc. All rights reserved