Clinical Profile of Elderly Atopic Dermatitis in China.

Background: With global population aging, elderly atopic dermatitis (AD) is emerging as a distinct subtype. This study investigated the clinical and hematological phenotype of elderly AD patients in a Chinese cohort. Methods: 593 patients who fulfilled the Chinese Criteria for Atopic Dermatitis (CCAD) were stratified into three age groups: 2-17, 18-59, and ≥ 60 years. Clinical features and risk factors were assessed via a standardized questionnaire and physical examination. Serum total IgE and complete blood counts were measured in a subset of patients along with age-matched healthy controls. Results: Approximately three-quarters of the elderly AD patients were late-onset (first presentation ≥ 60 years old), with male predominance (male-to-female ratio 2.03:1). Lesions displayed a "widespread" distribution pattern in elderly AD. Over 80% of elderly AD patients had moderate-to-severe disease (SCORAD ≥ 25), with greater pruritus, quality-of-life impairment, and worse management outcomes compared with younger groups. The endogenous subtype increased with age, accounting for 47% of elderly AD. The elderly AD had higher monocyte count and percentage but lower lymphocyte count than other age groups. The Eczema Area and Severity Index (EASI) positively correlated with eosinophil count, and negatively with lymphocyte count and percentage in elderly AD. Conclusion: Elderly AD exhibits a distinct clinical and hematological phenotype characterized by severe disease burden, widespread distribution, male predominance, and age-specific immune dysregulation. While the role of eosinophil is established, our findings underscore the need for age-tailored management strategies and highlight the monocyte-macrophage axis as a novel direction for future research.