Exploring Standardized Scales and Serum Biomarkers to Evaluate Changes in Pruritus due to Eczema after Japanese Kampo Treatment: A Prospective Case Series

BACKGROUND: We aimed to explore standardized scales and serum biomarkers for tracking changes in the symptoms and severity of pruritus due to eczema in patients treated with Kampo formulas. PATIENTS AND METHODS: This prospective, single-arm, pre-post comparison case series recruited patients with pruritus mostly due to eczema who consulted the Kampo Clinic at the Keio University Hospital from June 2019 to March 2020. The participants were prescribed a personalized Kampo formula for 12 weeks. Patient profiles and symptoms were assessed every 4 weeks using the visual analog scale (VAS), patient-oriented eczema measure (POEM) scale, 5-D itch scale (5D), Skindex-16, and eczema area and severity index (EASI). Blood biomarkers and intestinal permeability indicators were measured at the first consultation and 12 weeks later. RESULTS: Pruritus and eczema severity improved significantly over time. The VAS, POEM, 5D, and Skindex-16 scores were well-correlated. The serum interleukin-31 levels decreased significantly after a 12-week intervention. Changes in the interleukin-31 level correlated with the diamine oxidase level at week 0, suggesting the involvement of the Th2 immune system and intestinal permeability in the mechanism of Kampo formulas. CONCLUSION: The evaluated scales are suitable for evaluating subjective symptoms and eczema severity after Kampo treatment; further studies are required to verify the study findings.