Frictional properties of human skin: relation to age, sex and anatomical region, stratum corneum hydration and transepidermal water loss

Differences in the dynamic skin friction coefficients (mu) were investigated with respect to age, sex, and anatomical region. A total of 29 volunteers consisting of seven young females, seven old females, seven young males, and eight old males participated in the study. Measurements were obtained from II anatomical regions, namely, the forehead, upper arm, volar and dorsal forearm, postauricular, palm, abdomen, upper and lower back, thigh, and ankle. The friction data were compared with stratum corneum hydration and transepidermal water loss (TEWL). The dynamic friction coefficient did not vary significantly between age and sex groups but varied considerably among the anatomical regions of the body. The forehead and postauricular had the highest mu (0.34 +/- 0.02) while the abdomen had the lowest (0.12 +/- 0.01); the remaining regions had an average mu value of 0.21 +/- 0.01. Similarly, no sex differences were observed for TEWL and stratum corneum hydration. Capacitance was only significantly lower on the palms of the elderly. Regional differences showed a higher state of hydration on the forehead and postauricular as well as the upper arm, upper and lower back when compared with the volar forearm. TEWL was generally lower in the elderly on all anatomical regions except the postauricular and palm. A significant correlation was established between mu and capacitance for most regions. Between mu and TEWL significant correlation was observed only on the palm and thigh. These findings suggest that frictional properties of skin are dependent on more than water content or non-apparent sweating and the role of sebum secretion is suggested as one possible factor.     

经皮水分丢失与健康人性别、年龄、解剖部位的关系

通过经皮水分丢失（TEWL）来评价皮肤的屏障功能，并研究经皮水分丢失与性别，年龄，解剖部位的关系，参加本次实验的为健康志愿者共104名，其中女性53名，男性51名，分为5个不同年龄组，用与计算机相连的蒸发测定仪Darmalab TEWL探头测量。结果发现不同年龄组男女性别之间TEWL值均无显著性差异（P＞0．05），新生儿组TEWL值明显高于其他各年龄组（P＜0．05），老年组TEWL值低于其他年龄组。在8个不同部位测量中，经统计得到TEWL值顺序为：手掌＞额部＞颊部＝手背＞小腿＝背部＞前臂＝胸部。说明TEWL与性别无明显相关性，而与年龄相关，以新生儿最高，老年人最低，在身体各部位的测量中，四肢末端和暴露部位经皮水分丢失较高。     

Human labia majora skin: transepidermal water loss in vivo.

Transepidermal water (TEW) loss of normal vulvar and flexor forearm skin was measured in 12 subjects. A significantly elevated vulvar TEW loss was demonstrated. Depsite subcutaneous administration of atropine in seven subjects to eliminate eccrine sweating, no alteration in the elevated TEW loss was found. A significant anatomic and/or physiologic uniqueness of vulvar skin is demonstrated and warrants further investigation.     

健康儿童皮肤透皮失水率与角质层含水量的相关性研究

目的探讨角质层含水量与透皮失水率的相关性。方法 2021年10月至2022年6月在普宁市公共健康医疗中心、2所幼儿园及2所小学招募≤ 17岁健康儿童。用皮肤生理功能测量仪测量健康儿童左前臂屈侧和右胫前部位的透皮失水率和角质层含水量, 采用Pearson相关分析法分析不同年龄、性别儿童的透皮失水率与角质层含水量的相关性。结果共招募1 396例健康儿童, 年龄1个月至17岁, 男783例、女613例。在1 ～ < 12个月组, 除男童前臂部位的皮肤透皮失水率与角质层含水量无显著相关性外, 男童胫前和女童前臂及胫前部位的透皮失水率与角质层含水量均呈正相关(r值为0.283、0.404、0.420, 均P < 0.05);在1 ～ 2岁组, 男童前臂和女童胫前部位的皮肤透皮失水率与角质层含水量无显著相关性, 而男童胫前和女童前臂部位的透皮失水率与角质层含水量均呈正相关(r值为0.370、0.419, 均P < 0.01);在3 ～ 5岁组和6 ～ 11岁组, 除6 ～ 11岁组男童胫前的透皮失水率与角质层含水量无显著相关性外, 两组男女性其他部位的透皮失水率与角质层含水量均呈...     

面部糖皮质激素依赖性皮炎患者经皮水分丢失和皮肤含水量分析

目的 分析面部糖皮质激素依赖性皮炎患者的皮肤屏障功能。方法 将面部分为额部、鼻尖、下颌、双面颊、双侧口角的皮损区及左耳后无皮损区共8个点，分别测量95例面部糖皮质激素依赖性皮炎患者及25例健康对照者的经皮水分丢失（TEWL）和皮肤含水量。结果 与健康组相比，面部糖皮质激素依赖性皮炎组下颌、双侧口角、双面颊TEWL值均显著升高（t值分别为4.90，2.60，2.57，2.54，3.77，P < 0.01）；双侧口角、右面颊及额部的皮肤含水量均显著降低（t值分别为3.27，3.81，2.02，2.78，P < 0.05）。在8个测量点中，面部糖皮质激素依赖性皮炎组与健康组TEWL值均为下颌及双侧口角 > 双面颊及额部 > 耳后无皮损区；皮肤含水量降低均为下颌及双侧口角 > 双面颊及额部 > 耳后无皮损区。结论 面部糖皮质激素依赖性皮炎患者下颌、双侧口角、双面颊区域皮肤屏障功能受损，口周区域TEWL值较高，而面颊皮肤水分含量较少。     

Assessment of skin barrier function in podoconiosis: measurement of stratum corneum hydration and transepidermal water loss

Background Podoconiosis is a common cause of lymphoedema in barefoot workers in Ethiopia and other countries. It has severe consequences for patients’ physical function, quality of life and economic status. Aims To investigate stratum corneum (SC) hydration and transepidermal water loss (TEWL) in patients with podoconiosis compared with controls. Methods In total, 55 patients and 20 controls were recruited. For each study subject, SC and TEWL measurements were taken, along with foot and lower leg circumferences. Measurements were compared between the patient and control groups. Results Foot circumferences tended to be higher in patients with podoconiosis, with the mean foot:leg circumference ratio being 1·19 (95% confidence interval 1·11–1·28) times that for controls (P = 0·001). There was no detectable difference between patients and controls in TEWL values (P > 0·05); however, SC hydration was significantly lower in patients vs. controls for the foot (P = 0·004) and lower leg (P = 0·046) sites. Conclusions Patients with podoconiosis have significantly lower SC hydration in the skin of their lower legs and feet than controls, which may lead to cracking and splitting, and increased risk of lymphoedema and infection.     

The transient and cumulative effect of sodium lauryl sulphate on the epidermal barrier assessed by transepidermal water loss: inter-individual variation

The aims of the investigation were: 1) to study the inter-individual variation in time course of TransEpidermal Water Loss and of clinical manifestations after a 24-h single exposure to Sodium Lauryl Sulphate. This TEWL time course (expressed as the difference in TEWL between the day of patch removal and a subsequent day) reflected the epidermal barrier response to the damage caused by SLS; 2) to investigate the association between the TEWL time course after the single SLS exposure and the TEWL value after 4-day repeated SLS exposure (as a model for cumulative irritation). The 35 healthy subjects tested could be divided into four sub-groups according to the day of their maximum TEWL value after the single SLS exposure (days 2 to 5). For the whole group, inter-individual variation in TEWL course was most pronounced in the first days following the single SLS application. Moreover, there was an inverse relationship (R = -0.61) between TEWL course during the first days after the single exposure and the TEWL value after 4-day repeated exposures. It is concluded that this association illustrates the importance of an adequately responding barrier function against the continuous exposure to irritants in daily life.     

In vitro transepidermal water loss: differences between black and white human skin

In vivo transepidermal water loss studies are characterized by large inter-individual variability and biased by environmental effects and eccrine sweating. An in vitro technique for measuring transepidermal water loss (TEWL) was used to compare TEWL in two racial groups--blacks and whites. In both groups a significant correlation between skin temperature and increased TEWL was found (P less than 0.01). Furthermore, black skin had a significantly higher mean TEWL than white skin, corrected log TEWL 2.79 and 2.61 micrograms/cm2/h, respectively. The difference in TEWL between the groups could because measurements were made in the absence of eccrine sweating and other vital functions. The higher TEWL in black skin could be explained on the basis of a thermoregulatory mechanism. The anatomical and physiological differences in the stratum corneum between different races are discussed.     

In vivo relationship between transepidermal water loss and percutaneous penetration of some organic compounds in man: effect of anatomic site

Summary The relationship between the percutaneous penetration of four chemicals and transepidermal water loss (TEWL) was investigated in vivo in man as a function of anatomic site. The findings showed an appreciable difference in the permeability of the skin from one site to another with regard to both water loss and chemical penetration. In addition, independent of the physicochemical properties of the molecules administered, there was a linear relationship between TEWL and penetration. These data confirm both the importance of anatomic site in the degree of permeability of the cutaneous barrier and the utility of determinations of TEWL and percutaneous absorption in the evaluation of its functional condition.     

International guidelines for the in vivo assessment of skin properties in non‐clinical settings: Part 2. transepidermal water loss and skin hydration

Background

There is an emerging perspective that it is not sufficient to just assess skin exposure to physical and chemical stressors in workplaces, but that it is also important to assess the condition, i.e. skin barrier function of the exposed skin at the time of exposure. The workplace environment, representing a non‐clinical environment, can be highly variable and difficult to control, thereby presenting unique measurement challenges not typically encountered in clinical settings.

Methods

An expert working group convened a workshop as part of the 5th International Conference on Occupational and Environmental Exposure of Skin to Chemicals (OEESC) to develop basic guidelines and best practices (based on existing clinical guidelines, published data, and own experiences) for the in vivo measurement of transepidermal water loss (TEWL) and skin hydration in non‐clinical settings with specific reference to the workplace as a worst‐case scenario.

Results

Key elements of these guidelines are: (i) to minimize or recognize, to the extent feasible, the influences of relevant endogenous‐, exogenous‐, environmental‐ and measurement/instrumentation‐related factors; (ii) to measure TEWL with a closed‐chamber type instrument; (iii) report results as a difference or percent change (rather than absolute values); and (iv) accurately report any notable deviations from this guidelines.

Conclusion

It is anticipated that these guidelines will promote consistent data reporting, which will facilitate inter‐comparison of study results.     

Measuring transepidermal water loss: a comparative in vivo study of condenser-chamber, unventilated-chamber and open-chamber systems

Background/aims: Two main systems have been utilized for measuring transepidermal water loss (TEWL): open chamber and closed chamber. Yet, further validation and standardization studies may be necessary to reveal the sensitivity, precision, and robustness of these instruments. Methods: Three instruments are compared for their applicability to assess TEWL: unventilated chamber, open chamber and condenser chamber. The comparative study was performed on human forearm skin (n=6), in the normal condition (baseline), and after (1) 10 tape strippings on both arms, (2) moisturizer cream (Eucerin^®) and petrolatum application for 1 h, and (3) 1% sodium lauryl sulfate (SLS) aqueous solution and distilled water (as control) application for 20 min. Results: The condenser‐chamber system, was the only device among these three that could show the effect of tape stripping on TEWL values as compared with baseline (P<0.001). The effect of moisturization, in terms of % change of TEWL values after application of cream and petrolatum, did not show significant difference between devices (P>0.05). However, only the values obtained from condenser‐chamber device revealed a highly significant change as compared with baseline (P<0.001). Condenser‐chamber system could also discriminate between the effect of moisturizer and petrolatum on TEWL values (P<0.05). The change of TEWL values after SLS application was shown to be significant by unventilated and condenser‐chamber systems (P<0.05). However, none of the devices differentiated between the effect of water and 1% SLS solution applied for 20 min. The values obtained from all three instruments correlate well with each other (P<0.001). Conclusion: Our results highlight the differences between two closed‐chamber TEWL measurement instruments, which are designed based on different measurement principles. This may provide insights to find the best practice to improve the quality, precision and sensitivity of the measurements.     

Measurement of transepidermal water loss in localized scleroderma

Localized scleroderma (LS) is a disease characterized by fibrotic changes in the dermis. Connective tissue growth factor and transforming growth factor β2 are the main mediators of fibrogenesis; this, along with excessive connective tissue production, affects epidermal keratinocytes, and thereby contributes to the changed quality of skin barrier. The objective of this article was to study the objective measurement of the skin barrier quality in LS with transepidermal water loss (TEWL) meter. The measurements of TEWL were performed on LS plaques in all three stages of various body locations. Control measurements were made on the contralateral side of healthy skin. The difference between TEWL in LS area and the contralateral side of the healthy skin was evaluated. A higher average TEWL 7.86 g/m²/h (SD 5.29) was observed on LS plaques compared with the control measurements on healthy skin 6.39 g/m²/h (SD 2.77). TEWL average values decreased from the inflammatory stage, through the sclerotic and to the atrophic stage. The mean difference 1.301 g/m²/h (SD 5.16) was found between TEWL on LS plaques and on the contralateral healthy skin in 82 measurements, i.e., a higher TEWL was observed in LS. The difference was statistically significant with p = 0.0250. Although fibrogenesis in scleroderma is localized in dermis, the skin barrier changes can be detected.     

Intra-individual variation of irritant threshold and relationship to transepidermal water loss measurement of skin irritation

Irritant susceptibility studies have used either visual assessment or transepidermal water loss (TEWL) to determine subject response. We have developed a visual assessment method which determines subject irritant threshold. We examined the relationship between sodium lauryl sulfate (SLS) irritant threshold and TEWL measurements from normal skin and SLS patch tests. 19 subjects were recruited. The irritant threshold of each subject was measured and TEWL measurements made from the applied SLS patch tests. Individuals with a lower irritant threshold (easily irritated skin) had elevated TEWL levels compared to those with higher thresholds. The irritant threshold test had a low intraindividual variation. This study showed that the 2 methods grouped patients in a similar manner. The variation seen may reflect the different outcomes measured: irritant threshold visually assesses the skin inflammatory response while TEWL measures skin barrier modification.     

Skin hydration and transepidermal water loss in patients with a history of sulfur mustard contact: a case–control study

Background   Skin lesions are among the most common complications of contact with sulfur mustard.
Objective   This study was aimed to measure skin water content and transepidermal water loss (TEWL) in patients with a history of sulfur mustard contact.
Methods   Three hundred ten male participants were included in this study: 87 (28.1%) sulfur mustard–exposed patients with current skin lesions (group 1), 71 (22.9%) sulfur mustard–exposed patients without skin lesions (group 2), 78 (25.2%) patients with dermatitis (group 3) and 74 (23.8%) normal controls (group 4) The water content and TEWL of skin was measured at four different locations of the body: forehead, suprasternal, palm and dorsum of hand. Nonparametric statistical tests (Kruskal–Wallis) were used to compare the four groups, and P  < 0.05 was considered statistically significant.
Results   The mean age of participants were 44.0 ± 6.7, 41.9 ± 5.9, 43.8 ± 9.3 and 44.8 ± 8.9 years in groups 1 to 4, respectively ( P  = 0.146). Xerosis, post-lesional hyperpigmentation and lichenification were significantly more common in either sulfur mustard–exposed participants or non-exposed participants with dermatitis ( P  < 0.05). Skin hydration was higher in subjects with sulfur mustard contact than in non-injured participants ( P  < 0.05) in the dorsum and palm of hands and forehead. TEWL was significantly higher in participants only in suprasternal area and dorsum of hand.
Conclusion   Contact with sulfur mustard agent can alter biophysical properties of the skin-especially the function of stratum corneum as a barrier to water loss-several years after exposure.

Conflicts of interest

None declared.     

Epidermal hydration of psoriasis plaques and the relation to scaling. Measurement of electrical conductance and transepidermal water loss

Seventy-seven plaques of ten patients with psoriasis vulgaris were studied with measurement of electrical conductance (3.5 MHz), measurement of transepidermal water loss (TEWL), and clinical scoring of erythema, induration and scaling. Uninvolved skin of the same body region served as control. Findings were very distinct with decreased conductance and increased TEWL. Plaques with no or mild scaling did not differ from grossly scaly plaques. Scales of psoriasis do not seem to exert any major occlusive effect on the water evaporation. The inverse relation between conductance and TEWL indicates reduced water-holding capacity of psoriatic epidermis, being a very common feature.