A randomized two-sided placebo-controlled study on the efficacy and safety of atmospheric non-thermal argon plasma for pruritus

Background To look into new potential indications for physical plasma and because some reports suggest plasma having antipruritic effects, we investigated the treatment of pruritus that often represents a therapeutic challenge. Objectives To assess the efficacy and safety of cold atmospheric argon plasma as add-on-therapy in pruritic diseases. Methods We treated 46 patients with various pruritic diseases with cold plasma for 2min daily in addition to standard treatment. All patients served as their own control, when their pruritic disease was treated with argon gas (placebo). The outcome measure was a long-term and short-term reduction in itching measured by means of a visual analogue score (VAS). Results The VAS scores at baseline were comparable (plasma 4.57, SD 2.38, argon 4.34, SD 2.35). We did not find any significant differences in VAS reduction between plasma and argon: long-term VAS difference of 1.97 (SD 1.33) for plasma and 1.74 (SD 2.37) for argon [P=0.224, 95% CI: (0.15; 0.60)], short-term VAS difference of 1.92 (SD 1.33) for plasma and 1.97 (SD 1.29) for argon [P=0.544, 95% CI: (0.21; 0.11)]. In both groups, patients experienced a significant reduction of pruritus at the end of therapy compared to baseline [plasma 1.97 (P<0.0001), placebo 1.74 [P<0.0001)]. No relevant side effects occurred, and treatment was well tolerated. Conclusions Treatment with cold plasma did not result in higher pruritus reduction than treatment with placebo. A significant reduction of pruritus compared to no effect was found at the end of therapy in both groups. Both treatment options had similar safety profiles.