Validation and Banding of the ItchyQuant: A Self-Report Itch Severity Scale

Abstract

Because of the significant emotional and psychosocial impact of chronic pruritus, it is important to accurately assess and measure itch severity. This study aims to validate and apply clinically meaningful bands to the ItchyQuant, an illustrated self-report numeric rating scale (NRS) for itch severity. A total of 76 adults with chronic pruritus were recruited. Participants rated their itch on the ItchyQuant, on a traditional 11-point NRS, and with verbal categorizations (no, mild, moderate, or severe). There was a significant, high correlation between the ItchyQuant and NRS (>0.92, P < 0.0001), demonstrating concurrent validity. Significantly more patients (47.2%) preferred the ItchyQuant than the NRS (23.6%) or had no preference (29.2%), P = 0.0015. Significantly more patients found the ItchyQuant easier to use (45.8%) than the NRS (20.8%) or had no preference (33.3%), P = 0.008. The set of clinically meaningful bands with the highest weighted kappa coefficient of agreement (κ = 0.69) was as follows: 0 (no itch), 1-3 (mild itch), 4-7 (moderate itch), 8-10 (severe itch). The ItchyQuant is a clinically meaningful measure of itch severity, demonstrating face and concurrent validity, that many patients prefer and find easier to use when compared with a traditional NRS. We suggest that the ItchyQuant can be added to the existing armamentarium of itch severity scales. We plan to investigate the ItchyQuant further in cognitively challenged populations.