BACKGROUND: Psoralen-UVA (PUVA) and narrowband UVB (311-nm) therapy are considered to be first-line phototherapies for patients with moderate to severe psoriasis. To reduce side effects as a result of systemic resorption of psoralens, topical PUVA therapies have been developed and proven to be effective in the treatment of psoriasis. OBJECTIVE: We sought to evaluate the combination therapy of narrowband UVB plus cream PUVA on selected psoriatic plaques compared with narrowband UVB or cream PUVA alone. METHODS: A total of 30 patients (Psoriasis Area and Severity Index score of 8-15) were included in the randomized study. The combination therapy consisting of narrowband UVB whole-body irradiation followed by cream PUVA therapy for selected psoriatic plaques was evaluated in 10 patients with chronic plaque-stage psoriasis. For comparison, the therapeutic efficacy, number of treatments, and cumulative UV doses until remission (Psoriasis Area and Severity Index score < 4) of cream PUVA therapy or narrowband UVB alone was determined in 10 patients, respectively. RESULTS: Both monotherapies induced clearance of psoriatic lesions in all patients within 5 to 7 weeks. Mean number of treatments for cream PUVA was 24 +/- 5; for narrowband UVB was 21 +/- 3. The mean cumulative UVA dose was 45.0 +/- 16.3 J/cm(2) and the mean cumulative UVB dose was 17.1 +/- 4.1 J/cm(2). Combination therapy resulted in complete clearance of lesions in all patients after 3 to 4 weeks. Mean number of treatment was 14 +/- 2, mean cumulative UVA dose was 18.7 +/- 4.7 J/cm(2), and mean cumulative UVB dose was 8.2 +/- 3.3 J/cm(2). The number of treatments (P <.001, analysis of variance), UVA dose (P <.001, t test), and UVB dose (P <.001, t test) were significantly reduced compared with both monotherapies. CONCLUSIONS: Our results indicate that a combination therapy of narrowband UVB plus cream PUVA appears to have a significantly higher efficacy compared with either monotherapy. The cumulative UV doses were significantly lower in the combination therapy. We conclude that cream PUVA can be used in addition to narrowband UVB for areas that tend to clear less quickly than the rest of the body.