Serum occludin as a novel biomarker in adult atopic dermatitis: a pilot case-control study

Atopic dermatitis is a chronic inflammatory skin condition characterized by immune dysregulation and dysfunction of the epidermal barrier. Although occludin, a vital tight junction protein, is essential for preserving barrier integrity, very little is known about its potential as a serum biomarker in atopic dermatitis. This pilot case-control study measured serum occludin levels in 30 adult atopic dermatitis patients and 30 age- and sex-matched healthy controls between May and August 2025, using a commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kit. Findings showed serum occludin levels were significantly higher in atopic dermatitis patients (mean: 2.50 ± 1.10 ng/mL) compared to healthy controls (mean: 0.68 ± 0.69 ng/mL; p < 0.001), with levels showing a decreasing trend with age. Serum occludin exhibited high diagnostic performance [area under the curve (AUC) = 0.92] and represents a sensitive and specific, non-invasive biomarker for atopic dermatitis. These preliminary findings lay the groundwork for future studies exploring serum occludin as a potential biomarker for atopic dermatitis assessment.