Contact dermatitis is an inflammatory skin condition caused by exposure to various antigens and irritants. There are different types including allergic contact dermatitis caused by a type IV hypersensitivity reaction and irritant contact dermatitis from non-allergic causes. Symptoms include rashes, vesicles, bullae, and plaques. Diagnosis involves considering the location of the eruption, exposure history, and patch testing. Treatment focuses on eliminating the triggering agent and using topical anti-inflammatory creams or oral corticosteroids for severe cases.