DEAR EDITOR, Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by disrupted epidermal barrier functions. 1 The stratum corneum (SC) consists of corneocytes and a lipid-rich extracellular matrix, which plays a key role in epidermal permeability barrier functions. 2, 3 Major lipid constituents of the SC are ceramides, free fatty acids (FFAs), cholesterol and triglycerides. 2, 3 Staphylococcus aureus colonization is an important trigger of AD. 4 Comprehensive profiling of SC lipids using S. aureus colonization status, and association between S. aureus colonization and skin lipid composition have never been documented.

In our study cohort, 27 patients with AD and 15 healthy individuals with no history of skin disorders (age≥ 18 years) were enrolled under an institutional review board-approved protocol. All participants with AD had elevated transepidermal water loss (TEWL), thymus and activation-regulated chemokine (TARC)/CCL17, total serum IgE levels and eosinophil counts (clinical markers of AD severity) 5 compared with nonatopic participants before and after adjustment for age and sex (Fig. 1). We extracted SC lipids using a high-yield, one-step,