A substance that has a direct toxic effect or exposure to an irritant produces irritant contact eczema and a skin reaction can occur immediately or gradually after repeat exposure. Examples of substances that cause irritant contact eczema include acids, certain toilet bowl cleaners or drain cleaners, oven cleaners, detergents, ammonia, lye, cement, turpentine, and paint thinners.
Allergic contact eczema will trigger an immunologic response that causes inflammation called a skin allergy. Examples of substances that cause allergic contact eczema include poison ivy, poison sumac, poison oak, dyes, fragrances, leather, rubber compounds (gloves and shoes) and nickel (jewelry accessories). Itching and burning are common symptoms in both types of contact eczema.