TABLE 3.

Overview of the most important features of premature and full-term infants at birth and over the first few postnatal months relative to the benchmark of normal, healthy adult skin.

Skin feature	Premature infant	Full-term infant
Barrier integrity (TEWL, g/m2/hr)	Initially higher vs. FT and adult then decreases over time	Comparable to adults at birth
Hydration	Higher initially vs. FT and adult, decreases then increases	Initially lower vs. PT and adult, then increases
pH	Comparable to FT, higher vs. adult then decreases more slowly vs. FT	Comparable to PT, higher vs. adult, then decreases
Visual dryness/scaling	Lower vs. FT, comparable to adult then increases before decreasing	Higher vs. PT and adult initially, then decreases
Visual erythema	Higher vs. adult at birth and 2–3 months later	Higher vs. adult at birth and 2–3 months later
SC cohesion	Initially comparable to adults then decreasing before increasing again	Lower vs. PT and adult initially then increasing
SC thickness	Thinner vs. FT, adult	Thinner vs. adult
Microbiome	Less bacterial diversity than FT; decrease in richness followed by an increase	More diverse than PT
NMF level	Lower vs. adult, comparable to FT initially then increasing to higher than adult	Lower vs. adult, comparable to PT initially then increasing to higher than adult
Filaggrin (FLG) (stratum corneum)	Lower vs. FT at birth, higher vs. adults at birth and 2–3 months later	Higher vs. adults at birth and 2–3 months later
Filaggrin processing proteins (SC) a	Higher vs. adult 2–3 months after birth	Higher vs. adult 2–3 months after birth
Protease inhibitors/enzyme regulators (SC) b	Higher vs. adult at birth and 2–3 months later	Higher vs. adult at birth and 2–3 months later
Antimicrobial proteins (SC) c	Higher vs. adult 2–3 months after birth	Higher vs. adult 2–3 months after birth

^aFilaggrin processing biomarkers: FLG, FLG2, CASP14, ASPRV1, TGM1.

^bProtease inhibitors/enzyme regulators: PI3, SERPINB3, SERPINB4.

^cAntimicrobial proteins: S100A7, S100A8, S100A9, LFT, MPO.