Pruritus

We asked participants to self-assess their severity of pruritus. The worst case of pruritus anywhere on the whole body in the preceding 3 days was evaluated using a visual analogue scale (VAS). Participants were asked to rate their pruritus state using a 100-mm VAS graded from 0 (no pruritus) to 100 (worst imaginable pruritus). The severity of pruritus was classified as follows: no pruritus (VAS score = 0), mild 0 < VAS < 40 mm）, moderate (40 mm ≤ VAS < 70 mm), severe (70 mm ≤ VAS < 90 mm), and very severe (VAS ≥ 90 mm).⁹