Especially Sensitive Baby Skin
Although baby skin has the same number of layers as adult skin, it differs in some important anatomical and physiological characteristics from that of an adult:
- Baby skin is only one-fifth as thick as adult skin and therefore less resistant.
- Because the horny layer is much thinner and its cells less tightly packed, the barrier function of the horny layer is still very limited compared with that of an adult. This means that substances coming into contact with the skin can penetrate into deeper skin layers and be absorbed more easily.
- Less active sweat and sebaceous glands (i) make the hydrolipid film and protective acid mantle (i) in babies and small children still relatively weak. Sebaceous gland activity does not increase until the hormonal changes of puberty.
- The reduced pigmentation of the skin leads to a higher UV sensitivity. Although melanocytes are present , they are less active.
These differences make baby skin especially sensitive to chemical, physical and microbial influences, as well as more prone to drying out (i). Babies also have much more difficulty regulating body temperature because of their relatively large body surface, reduced sweat gland activity and the relatively slow adaptability of the skin’s circulation.
Especially close attention should be paid to the skin in the area normally covered by nappies. The occlusive effect of a nappy, combined with the irritating action of urine, faeces, sweat, and mechanical stress (for example rubbing) can cause the skin to become inflamed. An elevated pH (i) due to the action of bacteria on urea (i) (ammonia formation) activates tryptic enzymes which produce a skin-damaging contact noxa. Also playing an important role in the development of the skin problem known as nappy rash are faecal bacteria and the fungus Candida albicans.
From the fourth year on, the skin and its appendages slowly begin to fully mature. At puberty - at around 12 years of age – the structure and function of a child's skin correspond to that of an adult’s.