Failure of short-term psoralen and ultraviolet A light maintenance treatment to prevent early relapse in patients with chronic recurring plaque-type psoriasis.

Background: Photochemotherapy using psoralen and ultraviolet A light (PUVA) is a highly effective treatment option for patients with severe psoriasis. Maintenance treatment has been advocated to provide for sustained remission. However, only a few studies have been conducted to assess the efficacy of maintenance treatment and these have provided inconsistent results.

Methods: We performed a prospective intrapatient left-right comparison study in 34 patients with chronic relapsing plaque psoriasis. PUVA treatment for clearing was given four times weekly. After complete or near-complete clearing, all patients were placed on a halfside maintenance schedule with irradiation twice weekly and then once weekly for 4 weeks each. The psoriasis area and severity index score was determined at baseline, end of the clearing phase and at 2-monthly intervals after discontinuation of treatment.

Results: Using a short-term maintenance protocol, a moderate delay in relapse of psoriasis was observed in only three patients (8.8%; 95% CI: 1.8-23.6%). In the remaining patients (91.2%), maintenance treatment had no effect on the length of remission. The mean time interval until relapse without and with maintenance irradiation was 4.5 +/- 3.4 and 4.6 +/- 3.4 months, respectively.

Conclusion: Our data indicate that short-term maintenance treatment is not effective in preventing early relapse of psoriasis and should be avoided.