Scientific interview-
frequently asked questions at the dermatologist’s clinic
Answered by Dr. Christina Schnopp
Clinic and Polyclinic for Dermatology and Allergology, TU Munich
What is so special about baby skin? Can I use normal skin care products for my baby or does a baby’s skin need special products?
Healthy babies are already born with relatively well-developed skin. However, the top layers of skin, and especially the stratum corneum which plays a big role as a barrier, are much thinner than that of an adult in the baby’s first few months1,2. The skin cells are smaller and divide faster2, sweat and sebaceous glands have not been fully developed yet3 and so, for example, the sweating function has not fully developed yet and the fat content of the top skin layer is lower2.
These structural differences can increase the permeability of the baby’s skin. The transepidermal water loss (“transepidermal” = through the epidermis) as an indication for the barrier function of children’s skin varies strongly in the first year (the skin is at times 'less waterproof'). The formation of the barrier function of the skin takes at least until the end of the first year of a baby’s life.
Compared to adult skin, baby skin can absorb more moisture in less time, but can also lose it again more quickly. One reason for this could be the lower level of natural moisturising factors in the top layer of skin in babies under one year old4. Parallel to the higher percentage of water in the top layer of a baby’s skin is also a more pronounced (micro) texture, which increases the ratio of skin surface to body mass.
In the first few days after birth, the baby’s skin has to adjust from a wet environment to a dry environment. During this time the newborn loses its vernix, a mixture of fat and dead skin cells that served as a protective layer in the mother’s womb. From the second week on, the water content of the top skin layer increases quickly.
The pH value of a newborn’s skin is neutral (possibly because of the mildly alkaline amniotic fluid), in the first few days it decreases, without fully reaching the values of an adult in terms of an 'acid mantle'5. The higher pH value negatively influences different enzymes that serve to maintain the barrier function and this can cause irritation, especially in the diaper area.
That places special demands on skin care products for babies. Because the skin is potentially more permeable, and the relation of body surface to weight is much higher than in adults, the ingredients in baby skin care products must be absolutely safe. Also, everything must be avoided that could damage the skin barrier or could impede its development, e.g. by changing the pH value or dissolving the skin fats.
Traditional bars of soap (alkaline), for example, attack the skin fats and are therefore not suitable for babies.
1) Evans NJ, Rutter N. Development of the epidermis in the newborn. Biol Neonate 1986; 49: 74-80.
2) Stamatas GN, Nikolovski J, Luedtke MA et al. Infant skin microstructure assessed in vivo differs from adult skin in organization and at the cellular level. Pediatr Dermatol 2010; 27: 125-31.
3) Agache P, Blanc D, Barrand C et al. Sebum levels during the first year of life. Br J Dermatol 1980; 103: 643-9.
4) Nikolovski J, Stamatas GN, Kollias N et al. Barrier function and water-holding and transport properties of infant stratum corneum are different from adult and continue to develop through the first year of life. J Invest Dermatol 2008; 128: 1728-36.
5) Stamatas GN, Nikolovski J, Mack MC et al. Infant skin physiology and development during the first years of life: a review of recent findings based on in vivo studies. Int J Cosmet Sci 2011; 33: 17-24.
