There are two main causes of dry skin:
- a weakness in the keratin or a breakdown in the lipids. Keratin needs water to keep it healthy.
- lipids work as the mortar that bonds skin cells and help to form a tight, protective barrier. Dry skin occurs when the epidermis does not contain a sufficient level of these moisture rich cells.
This can be the result of either internal or external factors:
- Internal factors include stress, illness, drug therapy or heredity predisposition to dry skin.
- External factors affect the skin chiefly because it is permeable. This means that it can absorb moisture from the outside (in the form of face creams). However, it is permeable in both directions, so it can also lose moisture when humidity in the atmosphere is low.