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 2 min 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.