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Glycerol is a trihydroxy alcohol that has been included for many years in topical dermatological preparations. In addition, endogenous glycerol plays a role in skin hydration, cutaneous elasticity and epidermal barrier repair. The aquaporin-3 transport channel and lipid metabolism in the pilosebaceous unit have been evidenced as potential pathways for endogenous delivery of glycerol and for its metabolism in the skin. Multiple effects of glycerol on the skin have been reported. The diverse actions of the polyol glycerol on the epidermis include improvement of stratum corneum hydration, skin barrier function and skin mechanical properties, inhibition of the stratum corneum lipid phase transition, protection against irritating stimuli, enhancement of desmosomal degradation, and acceleration of wound-healing processes. Even an antimicrobial effect has been demonstrated. Topical application of glycerol-containing products improves skin properties in diseases characterized by xerosis and impaired epidermal barrier function, such as atopic dermatitis. The increase of epidermal hydration by glycerol is critical in skin conditions aggravated by dry and cold environmental conditions, e.g. winter xerosis. This paper provides a review on effects of glycerol on the skin, the mechanisms of its action, and the potential applications of glycerol in dermatology.

Sensitive skin is a frequent complaint in the general population, in patients, and among subjects suffering from itch. The International Forum for the Study of Itch (IFSI) decided to initiate a special interest group (SIG) on sensitive skin. Using the Delphi method, sensitive skin was defined as "A syndrome defined by the occurrence of unpleasant sensations (stinging, burning, pain, pruritus, and tingling sensations) in response to stimuli that normally should not provoke such sensations. These unpleasant sensations cannot be explained by lesions attributable to any skin disease. The skin can appear normal or be accompanied by erythema. Sensitive skin can affect all body locations, especially the face". This paper summarizes the background, unresolved aspects of sensitive skin and the process of developing this definition.

We report increased serine protease activities in acute eczematous AD, especially in deeper layers of the SC, including SC tryptase-like enzyme, plasmin, urokinase and leucocyte elastase activities. These elevations in protease activities were associated with impaired barrier function, irritation, and reduced skin capacitance. Increased SC cohesion was apparent despite elevated TEWL during tape stripping, which would indicate reduced SC thickness in acute eczematous lesions of AD. Indeed, this was observed using an estimate of SC thickness.

We demonstrated the relation of formation of an acidic pH as well as underlying mechanisms in the induction of a fully hydrated SC over the first weeks of human life as a dynamic functional adaptation.

Early postnatal life is a period of active functional reorganization and cutaneous physiological adaptation to the extrauterine environment. Skin as the outermost organ of mammalians is endowed of multiple functions such as protection, secretion, absorption and thermoregulation. Birth stimulates the epidermal barrier maturation and the skin surface acidification especially in premature infants. In full-term infants the developed stratum corneum accomplishes competent barrier function, in contrast to prematures. Complete barrier maturation in preterm infants is fulfilled by 2-4 weeks of the postnatal life. However, in preterms with 23-25 weeks gestational age this process takes longer. Versatile regulatory mechanisms, namely skin surface acidity, calcium ion gradient and nuclear hormone receptors ⁄ ligands are interrelated in the complex postnatal newborn adaptation. The skin of newborns is adjusting quickly to the challenging environmental conditions of the postpartum.However, certain functions, for example, microcirculation, continue to develop even beyond the neonatal period, that is, up to the age of 14-17 weeks. Different environmental factors (for instance, dry and cold climate, diapers and cosmetic care procedures) influence the postnatal development of skin functional parameters such as stratum corneum hydration and the permeability barrier especially in premature infants. The aim of this article is to summarize the current knowledge on skin physiology in newborn and infants with a practical approach and to discuss the possible clinical consequences. This review offers the readership a critical and practical overview of skin physiology in newborns and infants. It emphasizes possible new research fields in neonatal and infantile skin physiology.

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The concentration of PCA in the stratum corneum collected by tape stripping showed it to be a feasible biomarker of the FLG genotype.