Skin surface and stratum corneum proteins and lipids (SC)

The skin surface and stratum corneum (SC) represent the outermost layer of the epidermis, serving as the body's primary physical and chemical barrier against environmental stressors [StatPearls: NBK513299]. This structure is characterized by a bricks and mortar arrangement, where protein-rich corneocytes are embedded in a continuous matrix of specialized lipids, including ceramides, cholesterol, and free fatty acids [PubMed: 18254807]. The protein component is largely composed of keratin filaments and the cornified envelope, which provides structural rigidity and a scaffold for lipid attachment [PMC3175844]. Biological functions of this layer include preventing transepidermal water loss (TEWL), maintaining acidic pH to inhibit pathogen growth, and facilitating desquamation through enzymatic degradation of corneodesmosomes [PMC2835893]. In diseases such as atopic dermatitis, psoriasis, and ichthyosis, alterations in protein expression (e.g., filaggrin) or lipid composition lead to barrier failure and chronic inflammation [PubMed: 24656726]. Therapeutic strategies involve the use of emollients to restore lipid integrity, humectants to enhance hydration, and keratolytic agents to manage hyperkeratosis [PMC3175844]. Consequently, the stratum corneum is a major focus for topical drug delivery and dermatological health maintenance.

Other names

Stratum corneumSkin barrierHorny layerCornified envelopeEpidermal barrier

Drugs targeting the skin surface and stratum corneum act by physically sealing the surface (occlusion), attracting water into the tissue (humectancy), filling gaps between cells (emolliency), or chemically breaking down structural proteins to facilitate shedding (keratolysis) [StatPearls: NBK513299, PMC3175844].