Keratin and intercellular keratinous material in stratum corneum

The stratum corneum is the outermost layer of the epidermis, serving as the primary physical barrier of the skin (StatPearls, NBK554423). It consists of corneocytes, which are dead cells packed with keratin filaments, and an intercellular matrix containing lipids and proteinaceous structures like corneodesmosomes (PubMed, 22435313). Keratin provides mechanical strength, while the intercellular material regulates cell-to-cell adhesion and the natural process of desquamation (UniProt, P04264). In diseases such as psoriasis, ichthyosis, and acne, the normal process of shedding is disrupted, leading to hyperkeratosis and barrier dysfunction (StatPearls, NBK554423). Keratolytic drugs, including salicylic acid and urea, target this material by solubilizing the intercellular cement or denaturing keratin proteins to facilitate skin softening and exfoliation (PubMed, 22435313). These interactions are crucial for treating thickened skin conditions and improving the delivery of other topical therapeutics.

Other names

Stratum corneum keratinCorneocyte keratinIntercellular cementCorneodesmosomesKeratinous matrix

Keratolytic agents promote the shedding of the stratum corneum by disrupting the intercellular bridges (corneodesmosomes) and increasing the hydration of keratin, which reduces the cohesion between corneocytes (StatPearls, NBK554423; PubMed, 22435313).