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

Abstract

The skin is the largest organ of the human body. It provides several defensive and regulatory functions between the external environment and the internal tissues, including prevention of infection, maintenance of water content level, and reduced penetration of allergens and irritants. 1 The most important function of the skin is providing an effective physical barrier, which consists almost entirely of the epidermis, particularly its superficial layer -the stratum corneum (SC). 1 The SC serves as the principal barrier against the percutaneous penetration of chemicals and microbes. It is involved in the regulation of water release from the SC into the atmosphere, which is known as transepidermal water loss (TEWL). 1 The biophysical parameters of the skin, such as hydration, TEWL, skin surface pH, and elasticity, are all reflections of skin function. 2 Epidermal hydration or SC water content is assessed by measuring the electrical capacitance of the skin with a Corneometer ™ . 3 TEWL is considered to be one of the most relevant markers for measuring skin barrier function. [4][5][6][7]

“Normal” TEWL‐how can it be defined? A systematic review

“…45 Results mirrored the study by Bolton et al (2017), with the bathed forearm showing significantly higher TEWL values compared with the showered arm. 45 Fei et al 46 measured TEWL values on both volar forearms. 46 Scratching behaviour was simulated using a scalpel on one forearm, and sandpaper was used to simulate friction on the other.…”

“…were seen in a study conducted by Nitiyarom et al 45 They recruited 78 subjects who rested in a humidity and temperature-controlled room for 15 min before interventions were done. 45 One forearm of each subject was showered with tap water for 3 min and then dried;…”

“…the opposite forearm rested in a bath of water for 3 min before being dried. 45 A Tewameter TM300 was used to measure TEWL on the ventral surface of both forearms. 45 Results mirrored the study by Bolton et al (2017), with the bathed forearm showing significantly higher TEWL values compared with the showered arm.…”

“…45 A Tewameter TM300 was used to measure TEWL on the ventral surface of both forearms. 45 Results mirrored the study by Bolton et al (2017), with the bathed forearm showing significantly higher TEWL values compared with the showered arm. 45 Fei et al 46 measured TEWL values on both volar forearms.…”

“…60 Additionally, it has been proposed that adipokines cause the replacement of stratum corneum while leptin promotes the proliferation of fibroblasts and synthesis of collagen and that these factors account for the variation in TEWL based on BMI. 61 According to Nitiyarom et al (2021), bathing affects TEWL in that it results in immediate evaporation of excess watch which has accumulated in the stratum corneum, hence why most dermatologist recommend immediate moisturization after bathing in order to secure hydration in those with dry skin. 45 Additionally, Gfatter et al…”