Irritant contact dermatitis is a reaction caused by direct physical or chemical injury to the epidermis. The damage caused by an irritant leads to inflammation, manifested in the skin as erythema, edema, and scaling. The thin epidermis of infants and young children can be vulnerable to these exposures.

Irritant contact dermatitis should be differentiated from true allergic contact dermatitis, which is a delayed type-IV hypersensitivity (immune) reaction. Patients typically present complaining of a burning or stinging sensation early in the course of irritant contact dermatitis. Symptoms and a rash usually follow the exposure by hours if the irritant is strong; this is in contrast to allergic contact dermatitis, where symptoms are usually delayed by approximately 2 days following exposure. As the irritation becomes chronic and the skin continually inflamed, pruritus can become a predominant symptom.

Any body surface can be a location for irritant contact dermatitis. The hands are a common location in older children (see also hand dermatitis). The face and diaper area are commonly involved in younger children, such as in diaper dermatitis. Saliva in young babies who are teething or using bottles and pacifiers can cause irritant dermatitis on the cheeks and chin. Irritant dermatitis from cleansers used on toilet seats presents as dermatitis on the buttocks and posterior thighs.

Patients with a history of atopic dermatitis are particularly predisposed. Environmental factors include repeated exposure to water or frequent hand washing, hand sanitizers, soaps and solvents, fiberglass, mild acids, and alkalis. Dry air can also predispose to irritant contact dermatitis. Irritant contact dermatitis can occur at any age from infancy to adulthood.

Irritant contact dermatitis will improve when the child is no longer exposed to the irritant, such as a hand dermatitis that improves during summers and school breaks when a child is no longer using a particular hand sanitizer daily.