Validation of the Spanish Version of the Itch Severity Scale: The PSEDA Study

Abstract

Background and objectives The Itch Severity Scale (ISS) facilitates objective assessment of the intensity of pruritus. The aim of this study was to validate a Spanish version of the ISS in patients with atopic dermatitis. Material and methods A prospective epidemiological study was undertaken in patients diagnosed with atopic dermatitis at least 1 year previously and a control group without the disease. Patients with atopic dermatitis were stratified according to the status of the lesions (active or inactive) and questionnaires were completed at baseline and 3-month and 6-month follow-up. Data were collected on sociodemographic variables relating to atopic dermatitis (including the modified Eczema Area and Severity Index [mEASI]), concomitant disease, and patient measures such as ISS, Dermatology Life Quality Index (DLQI), and Children's DLQI (cDLQI). Results A total of 207 children (2-17 years) were included: 56 control subjects, 103 patients with active lesions, and 48 with inactive lesions. The mean (SD) age of the participants in this age group was 8.1 (4.0) years. A total of 261 adults (≥ 18 years) were included: 89 control subjects, 124 patients with active lesions, and 48 with inactive lesions. The mean age of the adult participants was 32.3 (13.4) years. A response rate of > 80% was obtained on the pediatric ISS (feasibility) and the responses correlated with the mEASI and cDLQI at baseline ( P < .001) as an indicator of validity. An effect size of 0.988 was observed (sensitivity to change) along with a Chronbach α of 0.840 (internal consistency). A response rate of >95% was obtained on the adult ISS (feasibility) and the responses correlated with the mEASI and DLQI at baseline ( P < .001) as an indicator of validity. An effect size of 1.0 was observed (sensitivity to change) along with a Chronbach α of 0.825 (internal consistency). Conclusions The Spanish version of the ISS is feasible, valid, sensitive to change, and displays good reliability based on internal consistency in both children and adults.