Ichthyosis Scoring System Can Be Applied Across Phototypes
Excellent interrater intraclass correlation coefficients seen for individuals with Fitzpatrick I to III, IV to VI skin types
By Dermsquared Editorial Team | July 11, 2025
WEDNESDAY, July 9, 2025 (HealthDay News) -- The Ichthyosis Scoring System (ISS) can be used across phototypes to measure the severity of ichthyosis, according to a study published online July 9 in JAMA Dermatology.
Angela J. Luo, from the Yale School of Medicine in New Haven, Connecticut, and colleagues examined the reliability of the ISS in individuals with Fitzpatrick IV to VI skin types in a cross-sectional study. Fourteen dermatologists used the ISS to rate 94 test photographs, 47 each from individuals with Fitzpatrick I to III and IV to VI skin types. Four body sites were chosen (upper back, legs, upper arm, and dorsal feet) due to limited comprehensive, high-quality photography among individuals with Fitzpatrick IV to VI skin types. Sixty-one patients with ichthyosis were represented in the 94 photographs. Interrater reliabilities were determined using intraclass correlation coefficients (ICCs).
The researchers found that scale and erythema ICCs varied from 0.97 to 0.99 and from 0.91 to 0.95, respectively, among individuals with Fitzpatrick I to III skin types. The corresponding ICCs varied from 0.97 to 0.99 and from 0.90 to 0.94 among those with Fitzpatrick IV to VI skin types. ISS reliability was demonstrated across phototypes by overlap of ICC confidence intervals.
"This cross-sectional study shows that validating the ISS in individuals with skin of color is a critical step toward ensuring that assessment tools fully capture disease severity, which is both a criterion for trial enrollment and a measure of therapeutic efficacy," the authors write.
Several authors disclosed ties to the biopharmaceutical industry.