Human newborn skin: the effect of isopropanol on skin surface hydrophobicity

The development of a hydrophobic skin surface in newborn mammals such as the rat plays an important role in promoting adaptation to the abrupt change in the environment that occurs at birth. To determine whether the skin surface plays a similar role in the human neonate, we performed tests of water sorption and desorption on the chest wall of 13 term newborns. These tests were performed within the first 24 h of life on unperturbed skin (controls) and after perturbation of a contralateral site with isopropanol. The degree of surface hydration was determined by measurement of skin surface electrical capacitance, and desorption rates were calculated by 1st-order kinetic analysis. The unperturbed surface of the newborn skin exhibited a peak sorption value (change from baseline after water loading) of 435 +/- 83 pF (mean +/- SEM) and a desorption rate of 0.048 +/- 0.009 s-1. After exposure to isopropanol, the peak sorption value increased to 594 +/- 79 pF (p < 0.05) and the desorption rate decreased to 0.024 +/- 0.004 s-1 (p < 0.01). Paired sorption values were positively correlated (r2 = 0.8, p < 0.001). These results support the hypothesis that the skin surface of the human newborn, by limiting the sorption of water (or amniotic fluid) on the skin, may play a role in the adaptation to the change in environment at birth.