The skin barrier, primarily comprised of cornified envelope, corneocyte lipid envelope, filaggrin, keratin, corneodesmosome, lamellar body, intercellular lipid matrix, and tight junction, maintains the homeostasis of internal systems by restricting transepidermal water loss and protecting the body from hostile environment. Genetic mutations, allergens, pathogenic microbes, and ultraviolet irradiations, may affect the structure, metabolism, and function of the skin barrier, result in dermatoses such as ichthyosis and atopic dermatitis. Further elucidation of the relationship of abnormalities in skin barrier structure and function to dermatoses would be beneficial to the development of more appropriate and effective assessment, management, and prevention strategies.