Date of Award


Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)



First Advisor

Keith A. Choate


Abstract: THE DEVELOPMENT AND VALIDATON OF A NOVEL ICHTHYOSIS SEVERITY ASSESSMENT INSTRUMENT. Qisi Sun, Amy Paller, Keith A. Choate. Department of Dermatology, Genetics & Pathology, Yale University School of Medicine, New Haven, CT.

Ichthyosis clinical trials require reliable, validated severity assessments to identify appropriate subjects and quantify treatment outcomes. There is no validated scale to measure ichthyosis severity across the entire body. We aim to create and validate a comprehensive and user-friendly instrument to measure total body ichthyosis severity in adults and children.We divided the body into 10 regions to score special regions of interest. Likert scales (0-4) were established to quantify scale and erythema, with descriptors and photographic standards. An 83-image teaching set was created from photographs of ichthyosis patients, Six dermatologists scored all test photographs twice to evaluate intra-rater reliability. Intra-class correlation coefficients (ICCs) determined the overall reliability of our instrument.

The ICC for combined scale and erythema scores across the entire body is 0.903 (95% CI, 0.77-0.974). ICCs for scale and erythema sub-scores are 0.911 (95% CI, 0.789-0.976) and 0.882 (95% CI, 0.723-0.968), respectively. Body sites exhibited moderate-good inter-rater reliabilities for scale, except elbows and lower extremities. Erythema reliabilities across all body sites were moderate-excellent. Intra-rater reliabilities were excellent (ICC >0.9).The ISS is validated as a comprehensive tool for assessing ichthyosis severity across the entire body.

Open Access

This Article is Open Access