A Single High-Dose 308-nm Excimer Laser in Treatment of Stable Plaque Psoriasis

Psoriasis is a chronic, genetically determined disorder affecting approximately 1-3% of population. Various modalities have been used for treatment of psoriasis, including ultra violet radiation (UV), narrowband UVB (311 nm) and 308 nm excimer laser. The excimer laser delivers high energy monochromatic ultraviolet (UV) at 308nm. Advantages of excimer laser over conventional UV sources include targeting of lesion, reducing cumulative dose and inducing faster clearance. This study evaluated the efficacy and adverse effects of a single high-dose 308-nm excimer laser in treatment of stable plaque psoriasis. Fifteen volunteers (8 males and 7 females) with plaque psoriasis were enrolled in the study whom had a mean age of 32.7±13. At the baseline, the mean Psoriasis Area and Severity Index (PASI) score was 10.9±1.9. The minimal erythematic dose (MED) was tested on unaffected skin of back or abdomen. Two plaques were selected, one plaque was treated with a single dose of either 8 or 12 multiples of MED, and the other on the opposite side was held as control. The patients and the PASI score of each lesion were evaluated 2 weeks, 1, 2, and 4 months after treatment. Ten patients showed significant (75% or more) improvement of PASI score within treated area compared with no change in the control areas. Three patients did not show any improvement. Generalized lesions of psoriasis developed in 2 patients, 2 and 4 months after treatment. There was no correlation between MED values and responsiveness. The response was not age and sex-related. In this prospective trial of treatment, 12 plaques of 10 patients showed significant improvement. This mode of treatment was well-tolerated. Only 2 patients complained of burning sensation and developed small vesicles which healed without scarring. These results suggest that single high-dose excimer laser can be considered as a valuable therapeutic option for treatment of selected forms of plaque psoriasis.