Topical steroids are used in addition to moisturisers (emollients) for treating eczema. Topical steroids reduce skin inflammation. A short course will usually clear a flare-up of eczema. Side-effects are unlikely to occur with short courses.
The terms eczema and dermatitis mean much the same. That is, an inflammation of the skin. It causes red, itchy skin which may also blister. There are two main types of dermatitis/eczema:
Atopic eczema. This is caused by a problem from within the body. If you have atopic eczema you are born with a tendency for your skin to become inflamed. Various parts of the skin tend to flare up with inflammation from time to time.
Contact dermatitis. This is caused by a substance from outside the body. This typically causes patches of inflammation on areas of skin which have come into contact with the substance. If you avoid the offending substance, the skin inflammation should go away.