Our clinic performs T.R.U.E. test allergy patch testing to help identify contact allergens and diagnose allergic contact dermatitis. Many persistent rashes are caused by sensitivity or allergy to common enviromental chemicals, such as nickel, formaldehyde, lanolin, parabens, and fragrance. T.R.U.E. test allows testing to 35 common allergens. Individuals with makeup reactions, persistent and recurrent rashes, and localized rashes on the eyelids, hands, scalp, or feet should consider testing. Individuals who suspect exposure to chemicals in their workplace as the cause of a rash should also consider testing.