Home > Encyclopedia of Children's Health > Contact Dermatitis

Definition

Contact dermatitis is the name for any skin inflammation that occurs when the skin's surface comes in contact with a substance originating outside the body. There are two major categories of contact dermatitis, irritant and allergic. Irritant dermatitis is essentially a direct injury to the skin, caused by such compounds as acids, alkalis, phenol, and detergents. The immune system is not involved in irritant dermatitis, and the person's skin is damaged without prior sensitization.

In allergic dermatitis, however, the patient's skin reacts to a substance to which it has become sensitized. A third type of dermatitis, photo contact dermatitis, is triggered by exposure of the skin to light following the application of certain cosmetics or chemicals. Photo contact dermatitis...