Associations of Total IgE, Eosinophils, and IL-5 with SCORAD-Defined Severity in High-IgE Atopic Dermatitis: A Retrospective Exploratory Study.

BACKGROUND

Atopic dermatitis (AD) is characterized by marked immune heterogeneity, and high-IgE AD is commonly associated with Th2-skewed inflammation and greater disease burden. However, the relationships between downstream Th2-related peripheral blood markers and multidimensional disease severity in high-IgE AD remain incompletely understood.

METHODS

This single-center retrospective exploratory study included adult patients with AD diagnosed between June 2023 and June 2025. Among 140 eligible patients with complete core data, 92 patients with high-IgE AD, defined as baseline serum total IgE ≥100 IU/mL, were included in the primary analysis. Patients were stratified according to SCORAD scores. Associations of total IgE, eosinophil (EOS) count, and IL-5 with SCORAD, EASI, NRS pruritus score, and DLQI were analyzed.

RESULTS

Total IgE, EOS count, and IL-5 levels were significantly higher in patients with SCORAD-defined moderate-to-severe high-IgE AD than in those with mild disease. Total IgE showed consistent positive correlations with SCORAD, EASI, NRS pruritus score, and DLQI, and remained statistically associated with SCORAD after multivariable adjustment. In exploratory logistic analysis, the IgE-EOS-log10(IL-5) combination showed moderate apparent discrimination for SCORAD-defined severity stratification, with an apparent AUC of 0.745 and a bootstrap-corrected AUC of 0.717. However, the combined marker set was not statistically superior to total IgE alone by the DeLong test.

CONCLUSION

Among the evaluated biomarkers, total IgE showed the strongest and most consistent association with multidimensional disease severity in adult high-IgE AD. Although the IgE-EOS-log10(IL-5) combination provided exploratory adjunctive information for SCORAD-defined severity stratification, it did not show statistically significant added value over total IgE alone. External validation is required before clinical application.