Fig. 1.

Change in perceived itch intensity from the baseline resting state (‘REST’) to the allergen-evoked itch state (‘ITCH’), on a 0–100 scale, for all experimental sessions (N = 14, with 2 sessions per subject). The dashed line indicates the “urge to scratch” threshold (defined at the 33 level). The thicker, black line represents the mean across subjects and sessions. The asterisk indicates that the ratings during ‘ITCH’ were significantly different from those during ‘REST’ (paired t-test, p < 10⁻⁷).