Contact dermatitis is a skin reaction that develops as a result of the skin's exposure to an irritating or allergenic substance. These substances can be any of the thousands of known potential irritants or allergens. There are two main forms of contact dermatitis: irritant contact dermatitis and allergic contact dermatitis. Irritant contact dermatitis is the most common type. In clinical assessment, distinguishing between these two types of reactions can sometimes be challenging.

Common agents that can cause contact dermatitis include:

* Cobalt
* Nickel
* Perfume components
* Solvents
* Latex gloves
* Detergents
* Hair care products
* Soaps and cleaning products
* Airborne irritants
* Certain plants
* Fertilizers and pesticides