title: Developmental Changes in Neonatal and Infant Skin Structures During the First 6 Months: In Vivo Observation.
abstract: OBJECTIVE
  Developmental changes of structures in neonatal and infant skin have not been well characterized. The purpose of this study was to clarify changes in skin structures during neonatal and infant growth in vivo.
  
  
  METHODS
  Fifteen healthy, full-term neonates (seven girls, eight boys) were studied. The measurements were performed 4 to 7 days (neonate) and 1, 3, and 6 months after birth on the buttock, upper thigh, and ventral forearm skin using a confocal laser scanning microscope. Developmental changes in dermoepidermal junction structures, stratum corneum thickness, epidermal thickness, and microvascular development were investigated.
  
  
  RESULTS
  A significant decrease in stratum corneum thickness was observed over the 3 months after birth. Dermal papillae were not observed in neonatal skin but were observed gradually over the next 3 months. Epidermal thickness, determined from the skin surface to the bottom of the epidermal layer, increased significantly from 4 to 7 days to 1 month of age, indicating the formation of dermal papillae and rete ridges. Complicated microvascular structures were observed in neonatal skin but disappeared gradually and were observed only at the dermal papillae at 3 months of age.
  
  
  CONCLUSIONS
  Our results reveal that infant skin is in a developmental stage structurally up to 3 months of age, paralleling skin functional and developmental maturation.
authors.affiliation: Biological Science Research, Kao Corporation, Ichikai, Haga, Tochigi, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyauchi
authors.affiliation: Department of Dermatology, Dokkyo Medical University, School of Medicine, Mibu, Shimotsuga, Tochigi, Japan.|Kamitsuga Hospital, Kanuma, Tochigi, Japan.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Shimaoka
authors.affiliation: Biological Science Research, Kao Corporation, Ichikai, Haga, Tochigi, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fujimura
authors.affiliation: Department of Dermatology, Dokkyo Medical University, School of Medicine, Mibu, Shimotsuga, Tochigi, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Koike
authors.affiliation: Kamitsuga Hospital, Kanuma, Tochigi, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Yatabe
authors.affiliation: Kamitsuga Hospital, Kanuma, Tochigi, Japan.
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Nishikawa
authors.affiliation: Kamitsuga Hospital, Kanuma, Tochigi, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Biological Science Research, Kao Corporation, Ichikai, Haga, Tochigi, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sugata
authors.affiliation: Biological Science Research, Kao Corporation, Ichikai, Haga, Tochigi, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Moriwaki
authors.affiliation: Department of Dermatology, Dokkyo Medical University, School of Medicine, Mibu, Shimotsuga, Tochigi, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hatamochi
mesh_terms: D000367:Age Factors; D002657:Child Development / Q000502:physiology*; D004817:Epidermis / Q000033:anatomy & histology / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018613:Microscopy, Confocal; D012016:Reference Values; D012494:Sampling Studies; D012867:Skin / Q000033:anatomy & histology* / Q000648:ultrastructure*