International guidelines for the in vivo assessment of skin properties in non‐clinical settings: part 1. pH

Abstract

BackgroundSkin surface pH is known to influence the dissolution and partitioning of chemicals and may influence exposures that lead to skin diseases. Non-clinical environments (e.g. workplaces) are highly variable, thereby presenting unique measurement challenges that are not typically encountered in clinical settings. Hence, guidelines are needed for consistent measurement of skin surface pH in environments that are difficult to control.MethodsAn expert workshop was convened at the 5th International Conference on Occupational and Environmental Exposure of Skin to Chemicals to review available data on factors that could influence the determination of skin surface pH in non-clinical settings with emphasis on the workplace as a worst case scenario.ResultsThe key elements of the guidelines are: (i) minimize, to the extent feasible, the influences of relevant endogenous (anatomical position, skin health, time of day), exogenous (hand washing, barrier creams, soaps and detergents, occlusion), environmental (seasonality), and measurement (atmospheric conditions) factors; (ii) report pH measurements results as a difference or percent change (not absolute values) using a measure of central tendency and variability; and (iii) report notable deviations from these guidelines and other relevant factors that may influence measurements.ConclusionGuidelines on the measurement and reporting of skin surface pH in non-clinical settings should promote consistency in data reporting, facilitate inter-comparison of study results, and aid in understanding and preventing occupational skin diseases.

Measurement of transepidermal water loss, stratum corneum hydration and skin surface pH in occupational settings: A review

“…The acidity of the skin provides an optimal environment for ceramide and lipid functioning, as well as normal functioning of enzymes. Furthermore, it is important for maintenance of the integrity and cohesion of the stratum corneum and homeostatic regulation of the skin barrier function . Acidic SSpH (below 5.0) is more beneficial for the general condition of the skin, when compared to skin with a pH above 5.0, as indicated by measurements of barrier function, moisturisation and scaling .…”

“…Measurements of TEWL, SCH and SSpH are affected by various endogenous, as well as exogenous factors, which have been discussed in detail elsewhere . Endogenous factors include the age, gender and ethnicity of the participants, anatomical positions on which measurements are taken, state of the skin (moisture, sweat, sebum, disease state), as well as genetic predisposition . Exogenous factors include ambient temperature, relative humidity, time of day, skin contamination, application of cleanser, creams or detergents, topical application of cosmetic products, occlusion and even topical antibiotics.…”

“…Besides the health effects, the impact that such exposure can have on the employee, as well as the employer, is of significant relevance. These include economic losses to both parties, due to decreased productivity, medical expenses and loss of work due to illness . It is therefore of utmost importance that the skin integrity remains intact throughout the entirety of a work shift—and over the span of an employee's career.…”

Effect of Fluid Intake on Hydration Status and Skin Barrier Characteristics in Geriatric Patients: An Explorative Study

“…The assessment of skin surface pH was conducted according to international guidelines [19]. Skin surface temperature (°C) was measured with the skin-Thermometer ST 500 (Courage and Khazaka Electronic).…”

Comparison of two kinds of skin imaging analysis software: VISIA® from Canfield and IPP® from Media Cybernetics

“…However, it is difficult to compare the results from different investigators or research institutions because of the influence of subjective factors and the low repeatability, which lead to limitation of academic communication. Over the last few years, some dermatologists, skin biophysical engineers, and cosmetic research centers have been working on the research of noninvasive measuring techniques and various devices, such as the Mexameter, spectrophotometer, reviscometer, silicone replicas, PRIMOS, and laser Doppler flowmetry, which were invented for noninvasive and dynamic identification of skin surface microscopic structure, mechanical rules, color change, secretion metabolism, and other physiological characteristics of the skin . Objective quantitative skin evaluation is based on these instrumental measurements, in which various biophysical parameters are measured.…”