You will be redirected to verify your credentials. Corresponding Author Russel M. Walters, PhD. The structure of the stratum corneum SC and the corresponding skin barrier develops from before birth up to about 4 years of age.
Your premature baby’s appearance | Raising Children Network
Large subject-to-subject variability within an age group requires a large population to observe trends in skin barrier properties over time. A better understanding of how skin hydration changes after birth suggests that barrier function may be related mechanistically to skin surface area expansion. The skin serves the critical function of providing a protective barrier between the body's viscera and the external world. The top layer of the skin, the stratum corneum SC , is largely responsible for regulating the transport of water and other substances through the skin.
Water loss through the skin is a significant health concern in preterm infants, and a better understanding of how skin barrier function evolves and reacts towards external factors is the first step to developing solutions for improved infant skin health [ 1 , 2 , 3 ]. To quantify these differences, the barrier function of the skin is commonly assessed by measuring water holding and transport properties, specifically the rate of water flux through the SC transepidermal water loss, TEWL and hydration state of the SC [ 4 ].
In addition to being a useful measure of barrier function, water content of the SC impacts skin cell proliferation, differentiation and desquamation, as well as the mechanical properties of the skin [ 5 , 6 ]. Infant skin differs from adult skin at the microstructural, functional and compositional levels, and these differences contribute to the clinically observed differences between infant and adult skin [ 7 , 8 , 9 , 10 ]. Previously, researchers found that in the first 15 days of life skin hydration is significantly lower compared with older infants and adults [ 11 , 12 , 13 ].
Approximately 2 weeks after birth, skin hydration has been observed to increase and even exceed values found in adults [ 7 ]; however, postnatal skin hydration development differs depending on the anatomical area [ 3 , 14 , 15 ]. Over the first years of life, skin hydration decreases to adult-like values [ 3 , 12 , 16 , 17 , 18 ]. Measurements of water content as a function of depth in the skin are greater in infants than adults [ 7 , 12 ]. Inconsistent changes with age in natural moisturizing factor NMF have been reported by several groups. NMF has been observed to be lower in infants up to 1 year of age than in adults [ 7 ].
However, another study contradicts this by reporting that infant NMF levels are not lower than adult levels [ 12 ]. NMF levels have been shown to be higher in newborns days of age than at 6 weeks or 6 months of age [ 12 ], which may represent a mechanism evolved to maintain skin hydration during this period of rapid adaptation.
TEWL varies by body site within subjects and can be variable within similar subject populations [ 7 , 10 , 19 , 20 ]. 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 ]. While a number of studies have considered age-dependent changes in TEWL and SC hydration and potential skin proteins e.
NMF that may cause these changes, the literature has barely addressed geometric changes in skin or considered how body growth and skin surface area growth may contribute to changing skin barrier properties [ 24 ]. However, there is converging evidence that these geometric properties may indeed be significant to barrier formation and functionality. Lipid sheets form between cells, creating a laminar barrier.
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As specific sites differentiate, cells spread like a front across the surface area of the developing infant [ 26 ]. The structure of the SC, including the aspect ratio of the corneocytes, lipid-to-corneocyte thickness ratio and offset ratio of corneocytes, affect TEWL as they influence the path length of water diffusion through the SC [ 27 ].
Such developmental changes could potentially be encapsulated by a gross metric such as the calculated skin surface area. Due to inter- and intrapersonal variability, assessing the skin barrier change with age requires a large number of subjects and preferably multiple body sites. In this study, we sought to determine how the SC structure and the resultant skin barrier properties change with a child's age and with changes in gross geometric skin properties as a child grows.
Children and mothers refrained from using topical products and cosmetics for at least 24 h prior to the study evaluations. TEWL and high-frequency conductance measurements indicative of moisture content in the SC [ 28 ] were obtained from the dorsal forearm and upper inner arm, enabling assessments of the effect of age and the environment e. The VapoMeter uses the closed-chamber measurement principle to determine the evaporation rate of water from skin [ 29 ]. All measurements were performed in triplicate at each body site.
Measurements were performed in a temperature- and humidity-controlled environment after a min acclimatization period. Image stacks a series of images from individual subjects were collected from the dorsal forearm and upper inner arm of 44 adult subjects. Useable image stacks of the upper inner arm measurement site were collected in infant subjects, and usable image stacks of the dorsal arm measurement sites were collected in infant subjects.
SC thickness was calculated through visual inspection of the image stacks. Although there are a number of related equations to calculate BSA e. Haycock et al. Average weights and lengths for neonates ranging from 24 to 42 gestational weeks were used to calculate average BSAs. These weights and heights were collected from Ahn [ 30 ] and the 50th percentile of the World Health Organization growth chart [ 34 ] for postbirth infants. Average weights for prebirth neonates ranging from 10 to 41 gestational weeks were calculated from Hadlock et al.
Adult BSAs were calculated using the Haycock equation [ 31 ]:. A similar procedure was used to fit a curve to the rate of change of BSA.
TEWL was elevated in infants compared with adults. Figure 1 shows the dorsal forearm TEWL from subjects, and the upper inner arm TEWL from subjects as a function of the subject age shown as weeks after conception. Both locations exhibit a decrease in TEWL with subject age from birth until about 4 years of age.
Stratum corneum and epidermis
TEWL values are generally higher in the upper inner arm diamonds than the dorsal forearm circles. Both individual subject values smaller symbols and average values by age group larger symbols are plotted. Individual subject values smaller symbols and average values by age group larger symbols are plotted. The linear correlation between TEWL and SC thickness is different in the upper inner arm diamonds and dorsal forearm circles. Averaging by age eliminates some of the variability of the TEWL measurement between subjects and more clearly illustrates the decreasing trend of TEWL with age until about 4 years of age.
For this analysis, we grouped data from multiple subjects into age bins in which average subject TEWL and average subject age are shown with large diamond and large circle markers fig. In order to have a similar number of subjects in each bin, seven infant age bins of variable age width mean of 23 subjects per age bin were defined. Since there were fewer young infants, the youngest age bins are wider in age.
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All 44 adults average age 32 years were placed into one age bin. Figure 1 b shows dorsal forearm SC thickness from subjects and the upper inner arm SC thickness from 71 subjects as a function of the subject age weeks after conception.
The SC thickness increases with age until 4 years of age, at which point the SC thickness is similar to that of adults. All subject data are shown in the small points. Large data points are age-bin averages, similar to the previous figure. There was a median of 11 subjects per bin for dorsal forearm SC thickness, and 7 subjects per bin for upper inner arm SC thickness. The SC thickness of the upper inner arm and dorsal forearm are similar, unlike the TEWL from the two sites which differ consistently.
Figure 1 c shows SC thickness plotted against TEWL at the dorsal forearm location, as well as the upper inner arm location for all age groups combined. The large circles and diamonds represent the same age bins from figures 1 a and b; however, in figure 1 b not all subjects had SC thickness measurements.
Therefore, data used in the analysis were included only when both SC and TEWL data were available for the same subject. The low TEWL of adults fig.
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Figure 2 shows BSA versus age in gray, where age is in weeks after conception and extends back before birth. As described previously, the BSA is calculated from average height and weight data at each age and a curve has been fitted to these calculated points. As the child grows from an embryo to an infant its BSA increases rapidly and continues to increase beyond 2 years of age through puberty, though at a lesser rate. On the secondary axis, the rate of change of BSA is plotted in black circles with four rolling average black lines using different fitter parameters. This is also known as cyanosis and is a sign that the child or person is not getting enough oxygen.
A doctor may suspect that an infant has blue baby syndrome during a regular checkup. Parents or caregivers who notice a bluish discoloration should schedule an appointment with a doctor. The doctor will begin the diagnosis by taking a thorough medical history by asking about any symptoms, feeding patterns, and the conditions at home. They will then perform a physical exam, looking at the discolored areas discoloration and listening to the heart and lungs. In addition to testing the baby, it is possible to get the tap water tested to measure the nitrate levels. Treatment will vary depending on what is causing the baby to turn blue.
If congenital heart disease is causing the discoloration, surgery may be required to correct the abnormalities. A surgeon will usually operate before the baby turns 1 year old, ideally at around 6 months of age, or even a little earlier. Successful surgery means that the baby will start to get more oxygen and will no longer look blue.