A comparison of PUVA-etretinate and PUVA-placebo for palmoplantar pustular psoriasis.

Seventeen patients with palmoplantar pustular psoriasis and three with hyperkeratotic psoriasis of palms and soles were treated with either PUVA-etretinate (1 mg/kg) or PUVA-placebo. Patients were randomly allocated to each group and the trial was conducted according to a double-blind protocol, so far as the side-effects of etretinate made this possible. PUVA was given three times a week for a maximum of 18 weeks, after 2 weeks on daily placebo or etretinate alone. All ten patients in the PUVA-etretinate group cleared, but there were four failures in the PUVA-placebo group (P = 0.03). The PUVA-etretinate treated patients required significantly fewer PUVA treatments (13.1 +/- 2.9; mean +/- s.e.) and cleared in a significantly shorter time (30.3 +/- 7.1 days) than the PUVA-placebo group (23.2 +/- 4.2 treatments; 59.2 +/- 11.5 days, P less than 0.05). The cumulative UV-A dose to clear was less in the PUVA-etretinate group (53.9 +/- 18.5 J/cm2) than the PUVA-placebo group (113.1 +/- 33.4 J/cm2). This difference was not significant due to the exceptionally large dose of UV-A used on one patient but the results were significant when it was excluded. The therapeutic advantage of adding etretinate to PUVA is offset by the side-effects of cheilitis, hair loss and peeling skin which occurred in eight of the ten PUVA-etretinate patients, and an increase in fasting triglyceride concentrations and serum alkaline phosphatase activity.