Biology and function of fetal and pediatric skin.

The development of the integumentary system is a series of events that starts in utero and continues throughout life. Although at birth, skin in full-term infants is anatomically mature, functional maturity develops during the first year of life. Pediatric skin transitions again with the onset of puberty. At each stage, there are changes in transepidermal water loss, skin hydration, and skin acidity that define the specific period of development.