Treatment of plaque-type psoriasis with the 308 nm excimer laser in combination with dithranol or calcipotriol.

The combination of excimer laser and topical treatment has not been studied in clinical trials. This within-patient comparison study evaluates the response rates of plaque-type psoriasis after treatment with topical only (dithranol or calcipotriol), laser only, and combination therapy with topical medication and laser. A total of 61 patients with psoriatic plaques located at symmetric body areas (PASI ≥ 6) were screened, 59 were enrolled, 54 completed treatment and 45 completed the 6 months follow-up. Treatments with the excimer laser were performed twice weekly until resolution or a maximum of 15 treatments. Each ointment was applied on one of the test lesions, which had to be at least 10 cm apart from each other. Efficacy was rated with a modified PASI score. At the end of the treatment phase only one patient in both topical therapy regimens met the criteria of partial clearance (modified PASI ≤ 2). The combined therapies resulted in 23 cases of partial clearance in both treatment arms. Four areas treated with calcipotriol, respectively six areas treated with dithranol resulted in total clearance at the end of the treatment phase. The average reduction of modified PASI scores was higher in combination than in topical treatment alone (49.8% calcipotriol + excimer versus 22.9% calcipotriol, 49.7% dithranol + excimer versus 26.8% dithranol). After six months there was a total clearance of 30.5% dithranol + excimer. Treatment of plaque-type psoriasis with laser in combination with topical treatment is a safe and effective therapy. The best long-term results can be obtained by the application of dithranol and excimer laser.