Novel Scoring System Shows Promise in Assessing Severity of Ichthyosis

Researchers have created a scoring system they say is proven reliable for measuring the severity of ichthyosis in adults and children.

Assessing the validity of their Ichthyosis Scoring System (ISS), the researchers concluded the system will be able to have a significant impact for both clinical use and research, allow for a more accurate assessment of disease burden, and enable better decision making and monitoring.

“There have been attempts to grade scale thickness and erythema with various instruments, such as optical coherence tomography and reflectance spectroscopy, respectively. However, we aimed to design an instrument that could be used regardless of clinical resources in settings ranging from medical missions to academic centers,” described the researchers in their paper, also noting that there are currently no scales that measure disease severity across the entire body. “Medical treatment of patients with ichthyosis requires a systematic method to evaluate global severity, but current grading systems provide limited use regarding whole-body disease burden.”

Publishing their findings in JAMA Dermatology, the researchers modeled their ISS after the Visual Index for Ichthyosis Severity—limited to 4 parts of the body—and the Ichthyosis Area Severity Index. Notable attributes of the novel scale include:

• Extensive scale descriptors, which slows for better reflection of the disease variability
• The documentation of site-specific disease severity for body parts that significantly affect the patient’s perceived severity of disease, including the face and palms
• Recognition of a different scoring basis for children, who have different proportions of body regions from adults

The reliability of the scoring system, which divided the body into 10 regions, was determined using 2 groups of dermatologists: a group of 6 who did not receive training in ISS scoring and a group of 5 who were formally trained.

Using 83 test photos of patients with ichthyosis amongst the dermatologists, the system showed significant reliability, with the researchers highlighting the notability of the findings due to the heterogeneity of patients used in the photos. Interclass correlation coefficients (ICCs) for total, scale, and erythema scores were 0.90, 0.91, and 0.88, respectively.

“Individual regions were assessed for interrater and intrarater correlations, ensuring that even individual scores could be used with accurate assessment,” noted the researchers. “Thickening and inflammation of palms and soles can be debilitating to patients, and the palms and soles display unique scale morphology, including yellow thickening, desquamative scale, and fissuring. As a result, these regions deserved their own set of scale descriptors and were included among the 10 sites.”

Among both groups of dermatologists, soles had the highest ICCs for scale. The dermatologists had the most challenges with assessing elbows and lower extremities, translating into lower ICCs. According to the researchers, this could be due to natural elbow wrinkles obscuring small adherent scales, particularly in older patients, and lower extremities having the largest surface areas, often with different scale severity.

Reference

Sun Q, Asch S, Bayart C, et al. Development and initial validation of a novel system to assess ichthyosis severity. JAMA Dermatol. Published online February 16, 2022. doi:10.1001/jamadermatol.2021.5917