Clinical phenotyping of atopic dermatitis using combined itch and lesional severity: A prospective observational study

Abstract

Background: Patients with atopic dermatitis (AD) have heterogeneous clinical phenotypes, including different combinations of itch and lesional severity. Little is known about the characteristics and course of these subtypes.

Objective: To determine the characteristics, associations, burden, and course of patients with AD using combined itch and lesional severity.

Methods: A prospective practice-based study was performed using questionnaires and physical examination (n=592). AD subsets were defined using verbal rating scale for average itch combined with either eczema area and severity index, objective-scoring atopic dermatitis (SCORAD), or validated investigator's global assessment as follows: mild-moderate itch and lesions (MI-ML), mild-moderate itch and severe lesions (MI-SL), severe itch and mild-moderate lesions (SI-ML), and severe itch and lesions (SI-SL).

Results: At baseline, there were only weak-moderate correlations of numerical rating scales for worst itch or average itch or SCORAD itch with eczema area and severity index, objective-SCORAD, body surface area, and validated investigator's global assessment (Spearman's rho = 0.32-0.62). Most patients had MI-ML (59.4%-62.3%), followed by SI-ML (21.3%-29.1%), SI-SL (6.0%-12.9%), and MI-SL (3.8%-6.4%). Patients with SI-SL, followed by SI-ML and MI-SL, described their AD as being more severe overall and had worse impairment in sleep, mental health, and quality of life. However, those with MI-SL or SI-SL were far more likely to be classified as severe by a physician (multivariable logistic and linear regression, P < .005 for all). Baseline MI-SL, SI-ML, and SI-SL were associated with similar longitudinal courses over time and more AD flares and itch triggers than MI-ML.

Conclusion: Combined itch and lesional severity seem to describe unique AD phenotypes. Further studies are needed to confirm these findings and understand the optimal treatments for these groups.