The pH of the skin surface and its impact on the barrier function

The `acid mantle' of the stratum corneum seems to be important for both permeability barrier formation and cutaneous antimicrobial defense. However, the origin of the acidic pH, measurable on the skin surface, remains conjectural. Passive and active influencing factors have been proposed, e. g. eccrine and sebaceous secretions as well as proton pumps. In recent years, numerous investigations have been published focusing on the changes in the pH of the deeper layers of the stratum corneum, as well as on the influence of physiological and pathological factors. The pH of the skin follows a sharp gradient across the stratum corneum, which is suspected to be important in controlling enzymatic activities and skin renewal. The skin pH is affected by a great number of endogenous factors, e. g. skin moisture, sweat, sebum, anatomic site, genetic predisposition and age. In addition, exogenous factors like detergents, application of cosmetic products, occlusive dressings as well as topical antibiotics may influence the skin pH. Changes in the pH are reported to play a role in the pathogenesis of skin diseases like irritant contact dermatitis, atopic dermatitis, ichthyosis, acne vulgaris and Candida albicans infections. Therefore, the use of skin cleansing agents, especially synthetic detergents with a pH of about 5.5, may be of relevance in the prevention and treatment of those skin diseases. Copyright (c) 2006 S. Karger AG, Base

Development and preliminary testing of a standardized method for quantifying excess water in over-hydrated skin using evaporimetry

Although evaporimetry (the measurement of water vapour flux density from the skin) has often been used to study the impact on skin hydration of using products such as baby diapers and incontinence pads, it is difficult to interpret results and to compare data from different studies because of the diversity of unvalidated methodologies used. The aim of this work was to develop a robust methodology for measuring the excess water in over-hydrated skin and test it on volar forearm and hip skin which had been occluded with saline soaked patches. Three repeat measurements were made on the volar forearm and the hip of five young (31–44 years) and six older (67–85 years) women and moderately good within-subject repeatability was found for both skin sites for both subject groups. Measurements taken from the hip were significantly higher (P = 0.001) than those from the arm and had larger coefficients of variation (3.5–22.1%) compared to arms (3.0–14.0%). There were no significant differences between young and older skin, implying that women for future studies could be recruited without regard to age. This is the first time that a robust evaporimetric methodology for quantifying excess water in over-hydrated skin has been described and validated, and it will form a solid basis for future wor

Quadro clínico e tratamento da dermatite da área das fraldas: parte II Clinical presentation and treatment of diaper dermatitis: part II

A dermatite da área da fralda irritativa primária é a mais prevalente desse tipo, sendo provavelmente a afecção cutânea mais freqüente na primeira infância. Constitui fonte significativa de desconforto para a criança. O uso da fralda ocasiona aumento da temperatura e da umidade locais. Há conseqüente maceração da pele, que se torna mais susceptível à irritação ocasionada pelo contato prolongado da urina e das fezes. Freqüentemente surge infecção secundária por Candida albicans ou por bactérias como Bacillos faecallis, Proteus, Pseudomonas, Staphylococcus e Streptococcus. O uso de pós, óleos, sabões e pomadas irritantes agravam o quadro clínico. A melhor conduta é a prevenção que engloba um conjunto de medidas que têm como objetivos manter a superficie seca, limitar a mistura e dispersão da urina e das fezes, reduzir seu contato com a pele, evitar irritação e maceração, preservar a função de barreira cutânea e manter, sempre que possível, um pH ácido. O tratamento médico consiste em medidas simples, ajustadas de acordo com a gravidade e o tipo de dermatite