Dermatitis is an inflammatory condition of the skin caused by external substances and agents coming into contact with the skin, as opposed to eczema which is principally a constitutional disease in which outside factors do not play a primary part.

However, in certain cases the terms “dermatitis” and “eczema” are interchangeable since eczema can also be due to both internal (endogenous) and external (exogenous) factors.

There are basically two types of dermatitis:

Irritant dermatitis - caused by substances irritating the skin due to constant contact, for example prolonged contact with water, soaps and detergents, chemicals, acids, abrasives, oils, solvents and alkalis. The rash is usually confined to the contact area.

Allergic Dermatitis - where the person becomes sensitised to the offending substance (allergen) - this is a cell-mediated immunological reaction. In this case the dermatitis will occur each time the person comes into contact with the allergen, even if in small amounts or for very short periods.