Dermatitis is basically the common term for any kind of rash and is sometimes used interchangeably with eczema.  Dermatitis can occur over any parts of the body; some have a cause and others doctors still don’t understand.  The complaint is basically a reaction from the skin to an irritation, scratching, dryness or an allergen.  What happens as a result of the constant scratching is a skin thickening or hardening.  Sometimes there can be a temporary dermatitis which is just a reaction to a substance that will only last a few hours or a day or two but when one is afflicted by chronic dermatitis, that can persist for longer.  It is often the hands or feet that can be affected by chronic dermatitis since they are usually susceptible to foreign substances or are in warm, moist conditions.  If you have chronic dermatitis you will have some kind of fungus and should get this checked out and treated sooner rather than later.  In such a case like this, you should make an appointment with a qualified dermatologist, such as Dr. Larry Jaeger, who works in the New York area.