Supplementary Material for: A Prospective Randomized Controlled Pilot Study to Assess the Response and Tolerability of Cold Atmospheric Plasma for Rosacea

Introduction: Rosacea is a common, facial, chronic inflammatory skin disease. Due to its complex pathogenesis, adequate therapy of rosacea can be challenging. An innovative recent therapeutic tool is cold atmospheric plasma (CAP), which is already established in the treatment of chronic wounds and promising in different other skin diseases. Methods: In a split-face pilot study we investigated dielectric-barrier-discharged CAP in erythemato-telangiectatic (ETR) and/or papulopustular rosacea (PPR). CAP treatment was applied on lesional skin of a randomized side once daily (90 seconds/area) for six weeks. The other untreated side served as control. Co-primary endpoints were ≥1 improvement of the Investigator Global Assessment (IGA) score on the treated side compared to control and a decline of the Dermatology Life Quality Index (DLQI) after six weeks. Secondary endpoints included inflammatory lesion count (papules and pustules), skin redness intensity and erythema size. Adverse events (AEs) were recorded constantly. Additionally, participants were weekly assessed for symptoms, skin condition, trigger factors, skin care, treatment success, and local tolerance parameters. All p-values were calculated using the Wilcoxon signed rank test. Results: Twelve subjects (ETR, n=3; ETR and PPR, n=9) completed the study. DLQI was significantly improved after six weeks (p=0.007). On the CAP-treated side, lesions (p=0.007) and erythema size (p=0.041) were significantly reduced compared to the control. IGA (p=0.2) and skin redness intensity (p=0.5) did not differ significantly between control and CAP-treated side. No serious AEs occurred and treatment was well tolerated. Conclusion: CAP is a promising new treatment of rosacea, especially for PPR.