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

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 alpha 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 alpha 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. (C) 2011 Elsevier Espana, S.L. and AEDV. All rights reserved.