What causes eczema?

Amy Paller, MD, FAAD, a dermatologist, explains how the skin and the immune system are involved when someone has eczema.

When a child has eczema, many factors can play a role in what causes it.
The skin plays a key role because normally our skin acts as a barrier, keeping out germs and other things that can harm us and sealing in water.
When eczema develops, the skin’s ability to act as a barrier diminishes.
A poor skin barrier causes the skin to lose water easily, which is why your child’s skin is so dry.
A poor skin barrier also lets in irritants, potential allergens, bacteria, and viruses more easily.
There is also a problem with the immune system, which tends to be shifted.
The immune system is shifted in such a way that it leads to the redness and itching that we see when a child has eczema.