An English-language version of an instrument evaluating itch-related cognitions is necessary as cognitions can add to a worsening of itch. Chronic itch is predominant in English-speaking countries as well as internationally. The objective of the study is to confirm the English version of the Itch Cognition Questionnaire in patients with chronic itch caused by psoriasis or atopic dermatitis.

The German Itch Cognitions Questionnaire was interpreted into English and cognitive interview was performed to finalize item wording. Internal and test-retest reliability, responsiveness to change, item discrimination, and convergent and discriminant validity were evaluated in a sample of 137 people with chronic itch related to atopic dermatitis or psoriasis that were recruited online.

The results of the Cognitions Questionnaire reveals that internal reliability was very high with Cronbachs alphas of 0.93 used for the Catastrophizing subscale and 0.88-0.90 for Coping. Pearsons correlation evaluating 1-month test-retest reliability for the Catastrophizing subscale was r = 0.62 and for the Coping subscale was r = 0.61. The revised item-total correlation showed that items were relatively consistent with the scores for the subscales (correlations range 0.58 to 0.79), signifying promising item discrimination. Factor analysis, convergent and discriminant, and sensitivity to change analyses offered evidence for validity.

This study revealed good psychometric characteristics of the English version of the Itch Cognitions Questionnaire. Future studies are required to assess the use of the measure in clinical practice to aid the treatment planning and outcome evaluation related to itch.

Source: Heckman CJ, Schut C, Riley M, et al. Development and psychometrics of the English version of the Itch Cognitions Questionnaire. PLoS One. 2020;15(3):e0230585. Published 2020 Mar 19. doi:10.1371/journal.pone.0230585