Skin hydration and transepidermal water loss after bathing compared between immersion and showering

Human body numerical simulation: An accurate model for a thigh subjected to a cold treatment

This article presents the development of a digital twin model of a thigh portion subjected to various thermal treatments. Two scenarios are investigated: cold water immersion (CWI) and whole body cryotherapy (WBC), for which the comparison of numerical results with experimental measurements validates the consistency of the developed model. The use of real geometry on a first subject demonstrates the high heterogeneity of the temperature field and the need for accurate geometry. A second subject with thicker adipose tissue highlights the impact of the subject's actual morphology on the validity of the treatment and the necessity to work with real geometry in order to optimize cold modalities and develop personalized treatments.

"Normal" TEWL-How Can it be Defined?: A Systematic Review

BACKGROUND

Transepidermal water loss (TEWL), the total non-eccrine sweat water evaporating from a given area of epidermis over time, is a measurement of skin barrier integrity. Skin diseases (e.g. psoriasis and atopic dermatitis) often result in transient increases in TEWL, so knowledge of "normal" TEWL values may be used to predict disease progression in dermatological settings. Variables such as age, race, and anatomic location have been suggested to affect TEWL, but current regulatory agencies have failed to control for additional variables of interest. Thus, this review summarizes variables that may cause TEWL variation.

METHODS

A comprehensive literature search was performed using Embase, PubMed, and Web of Science to find human studies that provided data on variables affecting TEWL.

RESULTS

31 studies, analyzing 22 affecting TEWL, were identified. Variables causing increased TEWL were mask-use (n=1), Dry Eye Disease (n=1), Chronic Venous Disease (n=1), Coronary Artery Disease (n=1), age (infants vs. adults) (n=4), nourishment in infants (n=1), stress within individuals (n=2), Body Mass Index (n=2), bathing versus showering (n=2), and scratching/friction (n=1). Variables with decreases in TEWL were genetic variability with SNPs on chromosome 9q34.3 (n=1) and cancer-cachexia (n=1).

CONCLUSION

We summarized 12 variables that impact TEWL and are not typically controlled for in experimental settings. Therefore, defining normal TEWL may currently be problematic. Thus, regulatory agencies should provide stricter guidelines on proper measurement of TEWL to minimize human introduced TEWL variation, and we should continue to examine factors impacting individual skin integrity.

Capacitance and transepidermal water loss after soaking in water for different durations: A pilot study

BACKGROUND

There is a scarcity of data on the effects of duration of bathing and cutaneous properties.

AIMS

This study aimed to investigate the changes of capacitance and transepidermal water loss (TEWL) after soaking in water for the different durations.

METHOD

This experimental biophysical study included healthy volunteers whose forearms were randomized to receive 3, 5, 10, 15, or 20 min of soaking of the volar aspect of the forearm. Skin hydration and integrity were assessed capacitance and TEWL measurement before and after soaking.

RESULTS

Sixty-five subjects (130 forearms) were enrolled with an average age of 33 ± 10.8 years. The change in capacitance after soaking for durations of 3, 5, 10, 15, and 20 min was 41.54 ± 14.57, 47.13 ± 11.80, 40.25 ± 14.95, 40.48 ± 14.19, and 39.97 ± 9.47 AU, respectively. The highest capacitance was observed after soaking for 5 min; however, there was no significant correlation between bathing duration and capacitance (p = 0.256). The capacitance measured immediately after soaking was at the uppermost level, but it rapidly decreased within 5 min. The change in TEWL after soaking for durations of 3, 5, 10, 15, and 20 min was 30.27 ± 9.74, 30.57 ± 7.45, 33.78 ± 9.25, 33.44 ± 7.24, and 35.13 ± 9.37 g/m² /h, respectively. There was also no significant correlation between duration of soaking and TEWL (p = 0.191); however, TEWL tended to increase with longer soaking duration.

LIMITATIONS

This study had a small sample size and measured only capacitance and TEWL. Future studies with more subjects, and that measure other physiologic parameters may further improve our understanding of the effect of bathing on skin.

CONCLUSIONS

There was no significant correlation between bathing duration and cutaneous properties including capacitance and TEWL. However, a 5-min soaking provided the highest skin hydration for healthy skin.