1. The skin's natural barrier
The skin is a natural barrier, made of tightly packed bricks (corneocytes) bound with mortar (lipids). Natural oil (sebum) sits on the skin's surface to slow water loss.
The bricks contain Natural Moisturising Factor (NMF) that attracts and retains water (hygroscopic). The bricks in healthy skin are swollen with water and fit tightly together, with no gaps.
2. The ups and downs of skin
Everybody's skin can fit at some point on a scale ranging from healthy skin to eczema.
Negative things such as washing with detergents, stress and central heating can move the skin down the scale.
Positive things such as emollient therapy and adding extra Natural Moisturising Factor can help move the skin up the scale.
3. When skin gets into trouble
In dry skin, there is less Natural Moisturising Factor to hold water in the bricks, and water is lost from the skin's surface.
The bricks can dehydrate, shrink and crack.
Mortar breaks down between the bricks and gaps appear.
4. Down the scale - Skin under attack
With the skin's natural barrier damaged, the skin is open to attack.
Irritants in the form of bacteria and allergens attack the skin.
Our body's own inflammatory chemicals then start to counter attack. Inflammation makes you itch.
Itching makes you scratch and and scratching further damages the skin.