. "Contact HypersensitivityPTNCI" . . . "Contact_Hypersensitivity"^^ . "C3668"^^ . "Contact hypersensitivity is an inflammatory response induced by antigen-reactive T cells that are exposed to antigen on the skin surface (epidermis). Poison ivy is a frequent cause of such reactivity, due to the urushiol from the plant, as are a variety of antigens derived from industrial exposure (e.g. rubber, chromate, nickel). These antigens induce the appearance of Th1-like T cells, which presumably produce IFN to activate macrophages.NCI" . "C0162351"^^ . "Disease or Syndrome"^^ . "Contact Hypersensitivity"^^ . "Contact Hypersensitivity"^^ .