Tools to study the severity of itch in 8-to 17-year-old children: Validation of TweenItchyQoL and ItchyQuant

Background/Objectives Validated pruritus-specific quality of life and self-reported severity instruments exist primarily for adults. Clinical trials to develop therapeutics for children with chronic pruritus are hampered by the paucity of appropriate outcome measures. To address this gap, we aimed to develop validated instruments to measure itch-specific quality of life and self-reported severity in children. Methods We conducted in-depth, open-ended interviews of itchy children and generated concepts to develop TweenItchyQoL. We administered TweenItchyQoL, ItchyQuant, a cartoon-annotated self-reported pruritus severity numeric rating scale (NRS), and a non-cartoon NRS to 175 itchy children aged 8-17 years. We analyzed the data for feasibility, preference, reliability, construct validity, and responsiveness. Results Average completion time was 4.8 minutes for TweenItchyQoL and 33 seconds for ItchyQuant. The majority of patients either preferred ItchyQuant or found no difference between ItchyQuant and the NRS. Cronbach's alpha for TweenItchyQoL total and subscales ranged from 0.84 to 0.95. Test-retest reliability coefficients were >= 0.7 for TweenItchyQoL and 0.4 for ItchyQuant. A 3-dimensional bifactor model was most appropriate (RMSEA = 0.048) on the confirmatory factor analyses. As a function of those reporting worsening, improvement, or no change at their final visit, TweenItchyQoL and ItchyQuant scores in those cohorts changed as expected. Conclusions This new set of validated and feasible instruments shows promise to quantify itch severity and QoL impact in older children.