Dermatitis is a group of skin conditions that
includes atopic dermatitis, allergic contact dermatitis, irritant contact
dermatitis and stasis dermatitis. The exact cause of dermatitis is often
unclear. Cases may involve a combination of irritation, allergy and poor venous
return. The type of dermatitis is generally determined by the person's history
and the location of the rash. For example, irritant dermatitis often occurs on
the hands of people who frequently get them wet. Allergic contact dermatitis
occurs upon exposure to an allergen, causing a hypersensitivity reaction in the
skin.