Transepidermal water loss (TWL) measurements in subjects having one of four distinct forms of ichthyosis were determined hygrometrically. The observed TWL was highest in epidermolytic hyperkeratosis but was significantly elevated above normal in all forms. The increased TWL rates through greatly thickened horny layers as compared to normal layers imply inefficient water barrier function of the stratum corneum in these disorders.
Frost P, Weinstein GD, Bothwell JW, Wildnauer R. Ichthyosiform DermatosesIII. Studies of Transepidermal Water Loss. Arch Dermatol. 1968;98(3):230-233. doi:10.1001/archderm.1968.01610150016002