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In the present work, nasolabial skin condition and the influence of seasonal changes during autumn and winter were studied in 16 healthy female volunteers. Apart from visual scoring of erythema and skin scaliness, transepidermal water loss (TEWL), skin hydration, apparent skin pH, skin colour and skin desquamation were biophysically measured. The study results showed that nasolabial TEWL was significantly higher during wintertime than in autumn. Also skin colour measurements and squamometry scorings revealed higher values, indicating a more reddish and scaly nasolabial skin during winter compared to autumn. Results from tape stripping and skin surface lipid analysis by high-performance thin-layer chromatography demonstrated significant differences for triglycerides and cholesterol esters, indicating a functionally inferior hydrolipidic layer during the winter season., (Copyright 2008 S. Karger AG, Basel.)

The acidic pH of the outer surface of the mammalian skin plays several important roles in the epidermal barrier function. The 2 endogenous pathways that are currently known to elicit this acidic pH are the generation of free fatty acids from phospholipids and the exchange of protons for sodium ions by non-energy-dependent sodium-proton exchangers. In this study, we propose a third endogenous pathway, i.e. epidermal ceramidase activity, generating free fatty acids from ceramides. By topical application of N-oleylethanolamine, a well-known ceramidase inhibitor, we could demonstrate a significant increase in the stratum corneum pH and a corresponding decrease in the epidermal free fatty acid content. Moreover, we could show that the resulting change in the apparent skin pH also provoked a delay in early barrier recovery and an increased epidermal desquamation, corresponding to earlier observations made for the already known endogenous mechanisms., ((c) 2008 S. Karger AG, Basel)

"La raison d'être" of the epidermis, as beautifully portrayed by Kathy Madison in The Journal of Investigative Dermatology (2003;121:231-41), describes the primary function of the skin: The terminal differentiation of an initially multipotent stem cell produces a protective, semi-permeable SC that permits terrestrial life. The permeability barrier function of the SC is provided by lipid bilayers lamellae surrounding anucleated apoptotic corneocytes. This structure has been described by Peter Elias as the "bricks and mortar" model where the bricks are the cornecytes and the mortar refers to the adjoining lipids. How important is the barrier to the skin? Certain genetic defects are characterized by profound barrier abnormaities due to alterations in either stratum corneum lipid metabolism or protein components of the corneocytes, producing ichthyotic genodermatosis. In this review, the mechanisms that drive barrier formation are summarized and this in the light of our recent scientific findings and publications in the domain of epidermal structure and function.

Background/aims: Squamometry is a combination of sampling corneocytes by adhesive coated discs followed by colour measurements after staining the cells. In this study, the correlation between stratum corneum (SC) hydration and scaling was investigated using capacitance measurements and squamometry, respectively., Methods: Stratum corneum hydration and assessment of barrier function by transepidermal water loss (TEWL) measurements were carried out on different sites of left and right volar forearm skin of female volunteers (n = 13; 24 +/- 3 years). D-Squame samples were taken on the same test spots., Results: Visual evaluation of the coloured samples by light microscopy and the development of a four-point-scale scoring system was found to be necessary to detect and minimise overestimation of chroma C* values. Capacitance measurements revealed neither significant differences between corresponding sites on left and right forearms no between different skin areas on the same forearm. Squamometric measurements, on the contrary, did not show any symmetry between corresponding test sites on both forearms or between different sites on one forearm. No correlation could be found between squamometric measurements and SC hydration values obtained at the same test sites. No skin barrier function impairment lays at the origin of this observation since TEWL values were found to be similar at all test sites in comparison to control skin. In a randomised single blind study, hydration and TEWL showed a significant improvement of 25% and 15%, respectively, after a 14-day application period of a moisturising cream. Although visual scoring of the coloured samples of both treated and untreated test spots revealed a good correlation with chroma C* values, the quantitative results found with squamometry were very doubtful., Conclusion: Squamometry with visual scoring can be proposed as a screening technique for SC hydration rather than a quantitative method to appreciate skin moisturisation.

In experimentally-induced irritant (ICD) and allergic (ACD) contact dermatitis, an oil-in-water (o/w) cream was applied to investigate its effects on a disturbed barrier function compared to untreated physiological barrier repair. Transepidermal water loss (TEWL) measurements were performed. Before the start of the experiments, the skin tolerance of the cream was examined, revealing the non-irritating characteristics of the ingredients and the absence of any contact allergic patch test reaction. In the ICD study, sodium lauryl sulfate (SLS) patches were applied to the forearms of young female volunteers. Consequently, it was observed that repeated cream application (14 days, 2x/day) significantly improved the TEWL of SLS-damaged skin, leading to a complete recovery on day 15. In the ACD study, disruption of skin barrier function was obtained by a nickel-mediated contact allergy patch (CAP) test. The cream was then applied 2x/day for 4 consecutive days. Assessment of TEWL clearly showed that recovery of the disrupted skin significantly improved after cream application in comparison to untreated barrier repair.

Background: Nickel (Ni) allergic contact dermatitis (ACD) alters the skin barrier., Objective: Our aim was to compare the efficacy of combination therapies on ACD, using a topical corticosteroid and a corneotherapy agent (barrier cream), with that of a single therapy with corticosteroids., Methods: On day 1, 3 Ni test patches were applied on each forearm of 14 Ni-patch-test-positive females. Four contained 5% Ni and 2 physiological saline. Either topical corticosteroid or barrier cream were matched with the combination of both products on 3 of the 4 Ni ACD. The fourth was not treated. Clinical scoring, transepidermal water loss (TEWL) and stratum corneum (SC) capacitance were measured before (day 1) and after (days 4-8) ACD., Results: The combination therapy showed a significant decrease in TEWL values and an increase in SC capacitance., Conclusion: Combining a topical corticosteroid with corneotherapy agents prevents the delay in the healing process of skin barrier disruption due to ACD., (Copyright 2001 S. Karger AG, Basel)