Dermatitis is an inflammation of the skin. It can have many causes and occurs in many forms. It usually involves an itchy rash on swollen, reddened skin.
Skin affected by dermatitis may blister, ooze, develop a crust or flake off. Examples of dermatitis include atopic dermatitis (eczema), dandruff and rashes caused by contact with any of a number of substances, such as poison ivy, soaps and jewelry with nickel in it.