The Structure of Your Skin
To understand how dry skin occurs, you need to know how the skin functions normally. Skin is not just an outer covering for our body but an important organ that makes up a sixth of our bodyweight. It has three different layers: the outer "horny layer", the epidermis and the dermis.
The Epidermis
The outer layer of the skin is 0.1 mm thick over most of the body, but much thicker on the palms of the hands and soles of the feet.
The epidermis is made up of special cells called keratinocytes, which contain a large amount of keratin. This is a particularly tough protein that also forms a major part of hair and nails. It normally contains 20 % water which helps to keep the skin soft, smooth and supple.
The skin maintains its moisture content also by producing the Natural Moisturising Factor. The NMF consists of lipids, urea, amino acids and lactic acid.
The dermis
This layer is found beneath the epidermis. The dermis contains the blood vessels that feed the skin, nerve endings which provide the sensation of touch, sweat glands and hair follicles.
Skin with the correct moisture content and maintained by an adequate level of lipids is an effective barrier against bacteria and fungi which can cause infections.
When the skin is deficient in water and/or lipid content, or when the horny layer is damaged, it can become dry, scaly, itchy, sore and open to infection. See: Causes of Dry Sensitive Skin
