IgE-defined endotypes reveal distinct clinical profiles of prurigo nodularis compared with atopic dermatitis: a multicenter study in China

Background Prurigo nodularis (PN) is a chronic inflammatory dermatosis that often coexists with atopic dermatitis (AD) but represents a distinct entity. Evidence directly comparing PN and AD in Chinese populations remains limited. Objectives To characterize clinical distinctions between PN and AD in Chinese adults and to explore whether total serum immunoglobulin E (IgE) status delineates distinct clinical profiles within PN. Methods This multicenter case–control study enrolled 2,621 adult patients (≥18 years) including 1,462 with PN and 1,159 with AD. Multivariable logistic regressions were used to evaluate independent associations differentiating PN from AD and to examine IgE-defined clinical heterogeneity within PN. Results Compared with AD, PN was independently associated with middle age, rural residence, lower education, smoking, and an overall reduced atopic profile, and was more frequently accompanied by type 2 diabetes mellitus and psychiatric disorders. Within PN, the IgE-high subgroup displayed a pronounced type 2 immune response-associated inflammatory profile, including peripheral eosinophilia and allergen sensitization, whereas IgE-normal patients showed comparatively attenuated atopic markers. In contrast, sociodemographic correlates that distinguished PN from AD were not consistently different between IgE-defined PN subgroups. Conclusions In Chinese adults, PN exhibits clinical heterogeneity with two distinct patterns: one characterized by variability in type 2 immunity-associated and atopic features, and the other by a substantial burden of specific sociodemographic and metabolic comorbidities. Serum IgE may serve as a practical marker for stratifying type 2 immunity and atopic variability in PN.