Rethinking Head and Neck Atopic Dermatitis: Pathogenic Axes and Emerging Therapeutic Directions
摘要
Head and neck atopic dermatitis represents a common and clinically challenging phenotype of atopic dermatitis, characterized by anatomical selectivity, chronicity, and variable therapeutic response. Increasing evidence indicates that head and neck atopic dermatitis is not merely a regional extension of generalized disease, but a distinct phenotype shaped by the convergence of regional barrier fragility, a lipid-rich sebaceous microenvironment, microbiome imbalance, particularly involving Malassezia species, and a mixed immune signature integrating type 2, type 17, and type 22 inflammatory pathways. These factors promote persistent inflammation, psoriasiform features, and relative treatment refractoriness in the head and neck region. The clinical relevance of this phenotype has increased in the era of targeted therapies, as persistent or de novo facial involvement has been reported during biologic treatment, most notably with interleukin-4Rα blockade. Dupilumab-associated head and neck dermatitis exemplifies a pathway shift characterized by suppression of type 2 inflammation alongside exaggerated interleukin-22 and aryl hydrocarbon receptor-driven epithelial stress responses, providing mechanistic insight into paradoxical inflammation and incomplete regional control. Advances in immunobiology are beginning to translate into more tailored therapeutic strategies. Interleukin-13-selective biologics, systemic and topical Janus kinase inhibitors, and emerging agents targeting tissue-resident memory T-cell pathways offer new opportunities to address the dominant inflammatory circuits active in this region. Although comparative data remain limited, these approaches raise the possibility of improved control in selected patients with difficult-to-treat head and neck involvement. This review synthesizes current evidence on the pathogenic hallmarks of head and neck atopic dermatitis, integrates emerging mechanistic and clinical data, and discusses evolving therapeutic strategies aimed at phenotype-driven region-specific management of this complex manifestation of atopic dermatitis.