Table 1: Functions of epidermal barrier components and possible protective role in prevention of atopic march.

Barrier component Type Function Possible role in preventing atopic march Claudin Tight junction protein Prevention of water loss Prevention of activation Desmoglein Desmosome formation Prevention of water loss Blocking allergen penetration Involucrin/envoplakin/periplakin Scaffolding protein Structural components to create epidermal barrier Allowing appropriate immunoregulatory T-cell environment Urocanic acid Chromophore Hygroscopic acid-base regulator/photoprotection Maintaining skin barrier function Filaggrin Protein Decreased permeability of water soluble molecules/epidermal differentiation Blocking allergen penetration Ceramide Lipid Contribution to skin permeability barrier and epidermal differentiation Blocking mast cell infiltration/expression of TNF Blocking Mast production of allergic cytokines. Blocking allergen penetration Skin protease inhibitors (SPINK) Protein Prevention of protease alteration in filaggrin and ceramide production Maintaining skin barrier function