Skin barrier function in infancy: a systematic review

Abstract

The skin of neonates and infants exhibits distinct anatomical and functional properties that might be clinically reflected by its characteristic susceptibility to skin barrier disruption. In this systematic review, we aimed to characterize skin barrier maturation as reflected by transepidermal water loss (TEWL) and skin surface pH during the first 2 years of life. We systematically searched MEDLINE and EMBASE via OVID from 1975 to 2013 to identify primary studies reporting TEWL and/or skin surface pH values in healthy full-term infants aged 0-24 months without any cutaneous diseases. After full text assessment, 36 studies reporting n = 8,483 TEWL measurements for 26 anatomical areas and n = 6,437 skin surface pH measurements for 14 anatomical areas were included. The mean age of the subjects ranged from 1.4 h to 1.2 years. The lowest pH of 4.63 was identified on the forehead at the age of 25.6 weeks, whereas the highest of 7.31 was on the volar forearm at 0.0 weeks. The lowest TEWL value of 3.1 g/m(2)/h was reported for the back at 0.6 weeks and the highest of 43.1 g/m(2)/h for the upper leg at 58.7 weeks. The skin surface pH reveals a steep decline during the first postnatal week, succeeded by a further gradual site-specific acidification process during the first month. A competent permeability barrier in most anatomical areas is indicated by TEWL, which does not exhibit a time-dependent development during the first 2 years of life.

Developmental Changes in Skin Barrier and Structure during the First 5 Years of Life

“…1, 4). However, TEWL also shows different postnatal development in other body areas [23]. In particular, we noted a decreased TEWL with increasing age from birth to adulthood concomitant with an SC thickness increase from birth to adulthood.…”

“…In conclusion, these data indicate that maturation of the skin barrier (reduction of TEWL, reduction of the rate of water mass loss, increase in SC thickness) takes place after the period of most rapid skin surface area expansion, corresponding to the second through to the fourth year of life, on the dorsal forearm and upper inner arm [23]. Mature skin barrier function is characterized by values in these parameters that are similar to those in adults.…”

“…There have been differing trends of TEWL with age reported in the literature [9,12,21]. In general, TEWL tends to be greater shortly after birth and tends to decrease towards adult values with age depending on the anatomical area [3,12,21,22,23]. …”

Early-life regional and temporal variation in filaggrin-derived natural moisturizing factor, filaggrin-processing enzyme activity, corneocyte phenotypes and plasmin activity: implications for atopic dermatitis

“…Adaptive changes, both in stratum corneum (SC) water‐handling properties and skin surface pH, occur in early life. In full‐term neonates, transepidermal water loss (TEWL) data suggest a competent epidermal barrier function shortly after birth …”

“…Structural differences between infant and adult skin have been reported. 5,6 Infant corneocytes are smaller than those of adults, correlating with a higher epidermal cell turnover rate compared with adults. 7 In contrast to adults, newborn babies do not show variation in corneocyte size between nonacral skin regions.…”