What is eczema or dermatitis?

Skin inflammation: Eczema is the formal term for dermatitis, which means skin inflammation. When most people talk about eczema, they are really referring to atopic dermatitis, which is an immunological condition that is driven by a lot of histamine release in the skin. This is different than, for example, nummular eczema, a coin-like rash that's a reaction to something else going on elsewhere on the body.

Dry skin rash: Eczema is a dry skin condition that usually appears as a red scaly or dry rash. Dermatitis is a no specific term to describe any rash or inflammation of the skin.