THE PHYSIOLOGIC ACID mantle of the healthy human skin, long acknowledged to be essential for the antibacterial defensive power of the skin, is established soon after birth. The characteristically neutral or alkaline skin reaction found in the newborn persists for only 24 to 48 hours. Thereafter, the surface pH turns acid, declining to about 6.0 during the first week of life, and to about 5.5 toward the end of the first month. This pattern has emerged from studies on full-size infants.1-3
It is still a matter of conjecture whether this pH conversion reflects the gradual activation of the mechanism by which normal skin acidity is maintained throughout life, or whether the observed pH changes are related to alterations in the morphology of the surface layers associated with the transition from intrauterine to extrauterine environment.
An investigation of the pattern of the pH changes in prematurely born infants was undertaken