Barrier Properties of Atopic Eczema Skin: Supramolecular Structure and Evaluation Method

As a barrier, the skin prevents organisms and xenobiotic substances, including toxins, from entering the body and protects the body from losing essential substances, especially water and electrolytes. This vital barrier function is compromised in diseased skin, particularly atopic eczema (AE), due to significant structural changes in the intercellular lipid of the stratum corneum. Unraveling the complex correlation between three key domains: lipid composition, structural lipid organization, and skin barrier properties, gives a valuable perspective on the prediction of disease severity and product efficacy. In this comprehensive review, the crucial role of the intercellular stratum corneum space on chemical movement across the skin is discussed first, along with the foundational stratum corneum model, as a basis for the lipid organization concept. Subsequently, data from the original articles concerning the direct effect of lipid composition on barrier properties were thoroughly discussed, aided by review articles, to draw the correlation between the three domains as stated previously. The synthesized results showed that in AE, levels of long-chain ceramides and fatty acids decrease. This reduction ostensibly compromises the skin's barrier function by diminishing the formation of essential orthorhombic crystalline structures and long-periodicity phases (LPPs).