Long-wave UV combo therapy may trump short-wave UV in psoriasis treatment

August 4, 2006

London -- A new study suggests that phototherapy with long-wave ultraviolet light, combined with a psoralen-class drug, may be more effective than short-wave UV therapy for treating patients with chronic plaque psoriasis.

London - A new study suggests that phototherapy with long-wave ultraviolet light, combined with a psoralen-class drug, may be more effective than short-wave UV therapy for treating patients with chronic plaque psoriasis.

The study, conducted by researchers at London’s St. Thomas Hospital, reports that among patients with lighter skin, the psoralen-UV-A (PUVA) therapy achieved better clearance rates with fewer treatments compared with short-wave therapy. The PUVA treatment also achieved longer periods of remission.

The study, reported in the July issue of Archives of Dermatology , involved 88 patients with chronic plaque psoriasis. Of these, 71 had skin types I though IV (and 17 had types V or VI. Half received twice-weekly PUVA treatments including the drug Deltapsoralen (8-methoxypsoralen), and half received short-wave UV therapy with a look-alike placebo.

Both treatments achieved low psoriasis clearance rates in patients with darker skin. But when the researchers focused on the 71 patients with lighter skin types, they noted that in this group, PUVA cleared psoriasis in significantly more patients (85 percent) than did short-wave treatment (65 percent).

The median number of treatments required until clearance was also significantly lower in the PUVA group (17 versus 28.5), and at six-month follow-up, 68 percent of the PUVA group remained in remission, compared with 35 percent of the short-wave group.

The study noted, however, that PUVA was associated with significantly more erythema than short-wave treatment (49 percent of patients versus 22 percent) and that two patients switched to another drug because of nausea, a known side effect of PUVA therapy. The study also noted previous research establishing that PUVA has a tendency to be associated with skin cancer after 160 to 200 lifetime treatments and that the treatment requires the use of eye protection, cannot be used during pregnancy and cannot be used in patients with hepatic impairment.

Given those caveats, the study concludes that because PUVA tends to clear psoriasis with fewer treatments and for longer remission periods, it can safely be used in treating appropriate patients.