A prospective study was conducted in 38 ichthyosis patients (20 children, 18 adults) to determine the reliability of 3 Likert scales to assess disease severity. The scales assessed skin scaling, erythema and hair loss. Ratings were done by the subject and 2 health professionals; each rater was blinded to the ratings provided by the other 2 raters. Test-retest validation was conducted with 21 patients who completed follow-up surveys a month later. The Likert severity scales had excellent inter-rater and test-retest reliability with intraclass correlation coefficient (ICC) of > 0.7, although the hyperkeratotic scale test-retest reliability was only moderate (ICC = 0.4). This pilot study offers promise for assessing disease severity in ichthyosis patients ...