How do i know if i have contact dermatitis?

Contact Dermatitis: Allergic contact dermatitis is a T cell-mediated, delayed-type hypersensitivity response. Contact allergens include metals, glues, plastics, rubber, fragrances, topical antibiotics, preservatives, and chemicals used in hair-care and cosmetic products. Avoidance is mainstay of treatment along with topical steroid creams. See an Allergist if you are concerned. Diagnosed by allergen patch testing.

Skin Irritants: A list of the top culprits that trigger skin reactions, or contact dermatitis. Some cause symptoms like redness, itchy skin, or inflammation.Some are triggered by an individual's allergy (contact allergic dermatitis) while other chemicals affect everyone (contact irritant dermatitis). http://www.webmd.com/skin-problems-and-treatments/features/dirty-dozen#1