Skin maturation from birth to 10 years of age: Structure, function, composition and microbiome

Area of Science:

• Dermatology
• Pediatric Physiology
• Microbiome Research

Background:

• Infant and adult skin physiology exhibit significant differences.
• Limited data exist on skin maturation in older children.
• Understanding childhood skin development is crucial for pediatric care.

Purpose of the Study:

• To investigate the maturation processes of healthy skin in children.
• To compare skin parameters across different pediatric age groups and adults.
• To analyze site-specific variations in skin physiology and microbiome during childhood.

Main Methods:

• Recruited 80 participants across four age groups: babies (0-2 years), young children (3-6 years), older children (7-9 years), and adults (25-40 years).
• Recorded key skin parameters including transepidermal water loss (TEWL), lipid compactness, stratum corneum (SC) thickness, corneocyte size, lactic acid, total amino acids, hydration, and melanin levels.
• Analyzed the composition of the skin microbiome on the dorsal forearm for each age group.

Main Results:

• Skin barrier function, including TEWL, lipid compactness, SC thickness, and corneocyte size, matures to adult levels by approximately age six.
• Babies and young children show higher lactic acid and lower total amino acids in the SC, indicating faster cell turnover.
• TEWL and skin hydration are consistently higher on the face than the arm across all ages.
• Skin pigmentation increases with age due to higher melanin levels.
• The skin microbiome differs significantly between children and adults, with Firmicutes dominating in children and Proteobacteria in adults.

Conclusions:

• Healthy skin physiology and microbiome mature throughout early childhood in a site-specific manner.
• Key indicators of skin barrier function reach adult levels by age six.
• Distinct developmental trajectories exist for skin physiology and microbiome composition during childhood.