 |
|
 |
|
 |
 |
|
 |
 |
 |
 |
 |
 |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PEDIATRICS Vol. 106 No. 1 July 2000, pp. 105-108
, §, 
,, §, , and, §,
From the Departments of * Dermatology and Neonatology, Rabin
Medical Center, Beilinson Campus, Petah Tiqva, Israel; § Schneider
Children's Medical Center of Israel, Petah Tiqva, Israel; and
Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv,
Israel.
 |
ABSTRACT |
|---|
Top
Abstract
Methods
Results
Discussion
Conclusion
References
|
|---|
Objective. The aim of the study was to investigate skin barrier function in neonates in different anatomic sites during the first 2 days of life.
Design. The study population consisted of 44 healthy full-term newborn infants. Transepidermal water loss (TEWL), stratum corneum hydration (SCH), and skin surface pH were measured in different anatomic sites (forehead, flexor part of forearm, upper back, abdomen, inguinal region, palms, and soles) during the first 10 hours of life and 24 hours later. Measurements were recorded with a Tevameter, a Corneometer, and a skin pH meter with a flat glass electrode. Results were compared with those in 20 healthy adults.
Results. TEWL was lower in infants than in adults in the forehead, palms, soles, and higher in the forearms. It was significantly higher on day 1 than on day 2 in the soles, palms, and forearms, and in the forearm, palms, and inguinal region compared with the other anatomic sites. SCH was significantly lower in the infants on the forehead, back, and abdomen, and higher on the forearms and palms; it was significantly higher on the first day of life on the forearms and palms, and lower in the inguinal region. Skin surface pH was significantly higher in the infants in all body sites (>6.6 in most measurements). On day 2, it was significantly lower than on day 1, but still higher than in adults. SCH correlated positively with TEWL in the neonates but not in the adults. None of the variables were related to gestational age, sex, mode of delivery, or body weight.
Conclusions. Changes take place in SCH, water loss, and pH in the first 2 days after birth, suggesting that the stratum corneum barrier is still in the process of adapting to extrauterine life. The significant anatomic variability in TEWL and SCH should be taken into account in evaluating the permeation of skin care products and topical medications in newborns. Key words: stratum corneum physiology, neonate skin barrier function, transepidermal water loss.
The most important function of the skin is to act as a
barrier, preventing dehydration from the loss of body water, poisoning from the absorption of drugs and chemicals, and systemic infection from
invading surface microorganisms.1,2 Although preterm
infants (gestational age: The aims of the present study were to compare TEWL, stratum corneum
hydration (SCH), and skin surface pH in different body sites among
full-term newborns in the first hours and on the second day of life and
adults, and to assess possible correlations among these variables as
well as among these variables and infant sex, gestational age, type of
delivery, and initial weight loss.
The study population consisted of 44 healthy newborn
infants, 21 males and 20 females, all appropriate for
gestational age of 37 to 42 weeks; 34 were delivered spontaneously and
10 by cesarean section. The research protocol was approved by the Human
Research Committee of Rabin Medical Center and Israel Ministry of
Health. Parental consent was obtained in all cases.
The infants were washed after birth with a wet towel and tap water to
eliminate the effect of the lipid biofilm. All had normal Apgar scores
and normal rectal temperature, and they were undressed for an
acclimatization period of 15 minutes. The infants were quiet before the
first nursing or at least 2 hours after. None of the infants were
receiving medication and none had clinical disturbances.
TEWL, SCH, and skin surface pH were measured on the forehead, upper
back, flexor part of the forearm near the cubital fossa, palms,
abdomen, inguinal region, and soles at 5 to 10 hours postpartum and
again 24 hours later. All tests were performed in open cribs in a
controlled environment, with room temperature from 22°C to 24°C and
humidity 50%. During the examination, skin temperature remained stable
in all the newborns, as was shown by the Tevameter device (Courage and
Khjazaka, Koln, Germany).
TEWL and SCH were measured with a combined Tevameter and Corneometer
(Courage and Khjazaka). The Tevameter device consists of a cylindrical
probe constructed of 2 hygrosensors and is designed to measure the rate
of water evaporation from the surface of the skin. TEWL was computed by
averaging the data recorded every 2 seconds for 90 seconds after
applying the probe to the skin. The Corneometer measures the electrical
capacitance of the skin surface as an indicator of SCH, which is
dependent on the high dielectrical constant of water content relative
to other skin components.8 Skin pH was measured with a
flat glass electrode pH meter8 (Skincheck, Hanna
Instruments, El-Hama, Israel).
The same measurements were performed in the same environment at all
sites except the inguinal region in a comparison group of 20 healthy
adult volunteers with a mean age of 24 years.
Statistical Analysis
Analysis of variance was used to compare differences between
newborns and adults and differences among anatomic regions.
Nonparametric techniques (Mann-Whitney U test and Spearman
rank correlation coefficient test) were used for direct
numerical comparisons of parameters not known to be distributed
normally. A P value of <.05 was considered significant for
all tests.
TEWL
The comparison between TEWL values in the neonates on day 1 and
the adults is shown in Fig 1. TEWL was
significantly lower in the neonates in the forehead (P < .001), palms (P < .001), and soles
(P < .001), and higher in the forearm
(P < .0001), with no differences in the abdomen and
back. The differences in TEWL values in the neonates between days 1 and
2 are shown in Fig 2. TEWL was
significantly higher in the soles (P < .01), palms,
and forearms (P < .001); there was no significant
difference in the forehead, back, abdomen, and inguinal region.
Regarding regional differences, the forearm, palms, and inguinal region
showed significantly higher TEWL values than did the other sites
examined (P < .05; Fig 2).
32 weeks) are known to have impaired skin
barrier function1,2 compared with term infants, the
properties of the variables relevant to skin barrier function in
different body areas during the first days of life have barely been
investigated. In 1 study of infants with transepidermal water loss
(TEWL), the technique of choice for evaluating skin barrier
function,3 no differences were found among 3 regional
sites,4 in contrast to reports in adults.5,6
In addition, studies have shown that the stratum corneum acidifies
during the first week of life.7 Because the skin has to
perform vital functions immediately after birth, such as
thermoregulation, dessication, and protection against damage from
several external factors, including microorganisms that it was not
exposed to in utero, the properties related to early stratum corneum
barrier function are an important issue of study.
METHODS
Top
Abstract
Methods
Results
Discussion
Conclusion
References
RESULTS
Top
Abstract
Methods
Results
Discussion
Conclusion
References
View larger version (21K):
[in a new window]
Fig. 1.
TEWL in infants and adults at different anatomic sites (mean ± standard deviation). Differences between the groups were statistically
significant for palms and soles and forehead and forearm
(P < .001).
View larger version (20K):
[in a new window]
Fig. 2.
Differences in TEWL between days 1 and 2 of life at different anatomic
locations. Differences were statistically significant for palms and
forearms (P < .001) and soles
(P < .01). Forearm, palms, and inguinal region had
significantly higher TEWL values than did all other examined sites
(P < .05).
SCH
Figure 3 shows the capacitance values on day 1 in the neonates, compared with the adults. SCH was significantly lower in the neonates on the forehead (P < .01), back, and abdomen (P < .05), and significantly higher on the forearms (P < .001) and palms (P < .01). On comparison of the neonatal values between days 1 and 2 (Fig 4), we found that SCH was significantly higher on day 1 in the forearms (P < .05) and palms (P < .005), and significantly lower in the inguinal region (P < .05). The forearms and palms showed significantly higher values than did the other regions examined (P < .05; Fig 4).
|
|
Skin Surface pH
Skin surface pH was significantly higher in the neonates than in the adults in all body sites (P < .01; Fig 5), with a mean of 7.08 ± .17 (range: 6.6-7.5), versus 5.7 ± .16 (range: 4.5-6.7), respectively. The pH values were significantly lower on day 2 in all body sites, compared with day 1 (P < .05; Fig 6), but they were still significantly higher than in the adults. No regional differences were noted in skin surface pH.
|
|
Correlations
SCH correlated with the TEWL in the newborns (P < .01) but not in the adults. None of the variables were found to be related to gestational age, sex, mode of delivery (spontaneous versus cesarean), or body weight. There was no correlation between the loss in weight between the first and second days of life and the difference in TEWL.
| |
DISCUSSION |
|---|
|
Top
Abstract
Methods
Results
Discussion
Conclusion
References
|
|---|
Ultrastructural studies have shown that the epidermis of full-term infants is morphologically indistinguishable from that of adults,9 and it is reasonable to assume that the biophysical properties are similar as well.10 The present study yielded 3 important findings: in the first 2 days of life, most anatomic sites show significant changes in the variables related to stratum corneum function; there are significant differences between the barrier variables of neonate and adult skin; and there are definitely regional differences in these variables in neonate skin. The finding that the TEWL value in newborns was lower than in adults in most of the anatomic sites indicates that infants have an effective barrier function against water, in agreement with other studies.1,2,11 Rutter and Hull1 also observed that the TEWL was relatively high in the first 4 hours of life and subsequently decreased, suggesting that the surface of the skin was drying out.1 It is of interest that these results are similar to those reported in elderly individuals, who have a lower TEWL than do young adults.5 The reduction of TEWL may reflect an adaptation to extrauterine life in the neonates and epidermal atrophy, resulting in a smaller water reservoir in the aged. Sweating was not a factor in our study, because baseline TEWL readings should not be influenced by sweating at temperatures between 22°C and 24°C and sufficient acclimatization.3 Another possible explanation for the low TEWL in newborns is the effect of the vernix caseosa. Although much of the vernix was removed immediately after birth in our series, there may be exogenous lipids that cause surface hydrophobicity without abnormal patterns of desquamation. There may also be a difference in composition of skin surface lipids in newborns.12 Neonate skin has been reported to have lower levels of enzyme activity than adult skin, and adult levels are not reached until 6 to 12 months of age.13 The skin lipid profile of 5-day-old infants after daily washing was reported to be similar to that of adult skin.12
The SCH was significantly lower in the newborns than in the adults, providing support for the clinical observation that newborns have dry skin.14 The TEWL and hydration in the forearm, near the cubital fossa, were exceptionally higher. A possible explanation for these findings is the predominant flexion pronation of the forearm in infants in the first days of life. Indeed, the high values may explain why atopic dermatitis does not appear in this classical flexural site in neonates. Further studies should test these variables during early childhood at different flexural sites.
Our study clearly demonstrates significant regional differences in TEWL and SCH. This is in contrast to the study of Orsmark et al,4 who found no difference in the TEWL in the abdomen, buttocks, and forearm of newborns. However, other studies2,11 support our results, showing higher values of TEWL in the palms and soles. These differences were attributed to background emotional sweating at these sites, but this cannot explain the high TEWL in the forearms found in our study.
The positive relationship between SCH, as reflected by the capacitance measurements, and TEWL in newborns indicates that the electrical properties of newborn skin may provide an indirect measurement of TEWL; this has also been suggested by Saijo and Tagami,14 Muramatsu et al,15 and Okah et al.16 The question remains as to why this correlation exists in the skin of full-term infants but not in adult skin.
Our study shows that skin surface pH values in newborns are significantly higher in all body sites than those in adult skin. This corresponds with the findings reported by others.7,17 Using the colorimetric method, Behrendt and Green7 tested skin pH at 3 sites immediately after birth in full-term infants and noted a pH >6 in nearly all readings; on the second day of life, more than one half of the recorded values were <6; and on the third and fourth days, there was a further trend toward acidity, with stabilization at values similar to those in adults within the first month of life. The high skin pH may be caused by differences in the chemical composition of the skin surface lipids and enzymatic activity.17 In view of the high skin pH in healthy newborns, we recommend that they not be exposed to alkaline soaps and detergents, which may inhibit the stabilization process and irritate the physiologic protective acid mantle.
The skin of newborns is known to be relatively susceptible to irritants. This cannot be attributed to a reduced skin barrier function, which has been found by all studies to be effective based on TEWL. The findings in our study suggest that although TEWL is relatively low in most body sites, other variables related to stratum corneum function, such as skin pH and SCH, may enhance the irritant potential of compounds on newborn skin.
| |
CONCLUSION |
|---|
|
Top
Abstract
Methods
Results
Discussion
Conclusion
References
|
|---|
Changes take place in SCH, water loss, and pH in the first 2 days after birth, indicating that the stratum corneum barrier is still in the process of adapting to extrauterine life. There is a significant anatomic variability in TEWL and SCH, and this should be taken into account during evaluations of the permeation of skin care products and topical medications in newborns.
| |
ACKNOWLEDGMENTS |
|---|
This study was supported by the Hia Sylvia and Citrinik Fund of Tel Aviv University, and by the Rabin Medical Center Fund for Young Investigators.
We thank Gloria Ginzach and Marian Propp for their editorial and secretarial assistance.
| |
FOOTNOTES |
|---|
Received for publication Mar 9, 1999; accepted Jan 6, 2000.
Address correspondence to Ayala Maayan-Metzger, MD, Neonatal Intensive Care Unit, Schneider Children's Medical Center of Israel, Petah Tiqva, 49202, Israel. E-mail: maayan{at}flashmail.com
| |
ABBREVIATIONS |
|---|
TEWL, transepidermal water loss; SCH, stratum corneum hydration.
| |
REFERENCES |
|---|
|
Top
Abstract
Methods
Results
Discussion
Conclusion
References
|
|---|
This article has been cited by other articles:
 |
|
 |
|
  R.-P. Charles, M. Guitard, C. Leyvraz, B. Breiden, M. Haftek, Z. Haftek-Terreau, J.-C. Stehle, K. Sandhoff, and E. Hummler Postnatal Requirement of the Epithelial Sodium Channel for Maintenance of Epidermal Barrier Function J. Biol. Chem., February 1, 2008; 283(5): 2622 - 2630. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Sugiyama, H. Arakawa, K. Ozawa, T. Mizuno, H. Mochizuki, K. Tokuyama, and A. Morikawa Early-Life Risk Factors for Occurrence of Atopic Dermatitis During the First Year Pediatrics, March 1, 2007; 119(3): e716 - e723. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
||
|
||
Home | My Pediatrics | Journal Information | Current Issue | Past Issues | Subscriptions & Services | Contact Us Click here for faster international access © 2000 American Academy of Pediatrics. All rights reserved. |
||
|
||
