The nurse recognizes which as type IV (delayed hypersensitivity) reactions? (Select all that apply.)

Choice A reason: Metal-induced skin irritation, such as from nickel in jewelry, is a classic example of contact hypersensitivity, a subtype of type IV hypersensitivity. It involves T-cell mediated immune responses to haptens bound to skin proteins. Choice B reason: Contact dermatitis is a prototypical type IV hypersensitivity reaction. It results from T-cell activation in response to environmental allergens like poison ivy, latex, or chemicals. Choice C reason: Sarcoidosis is a granulomatous inflammatory disease, but it is not classified as a type IV hypersensitivity reaction. It involves complex immune dysregulation and is not triggered by a specific antigen in the same manner. Choice D reason: Drug-induced hemolytic anemia is a type II hypersensitivity reaction, mediated by antibodies targeting red blood cells. It does not involve delayed T-cell mediated mechanisms. Choice E reason: A positive PPD test is a classic example of type IV hypersensitivity. It reflects a delayed T-cell response to Mycobacterium tuberculosis antigens previously encountered by the immune system.