Contact dermatitis is an itchy skin reaction induced by repeated exposure to an irritative external agent (direct tissue damage), or allergic (tissue damage caused by a reaction of type IV delayed hypersensitivity in a previously sensitized individual). The most frequent cynical expression is dermatitis or eczema, of a polymorphous inflammatory pattern characterized in the acute phase by erythema, vesicles, or blisters, and in the chronic phase by drying, lichenification, and fissures. More than 3700 allergens have been identified which are capable of provoking allergic contact dermatitis in humans. The most frequent locations are the hands, feet, eyelids, and lips. Skin tests remain the standard for correct diagnosis of allergic contact dermatitis. Their treatment entails removal of the causative agent, along with protective measures and regeneration of the damaged skin.
