Which clinical manifestation should a nurse practitioner expect in a patient having a hypersensitivity reaction?

In a hypersensitivity reaction, one of the most common clinical manifestations is urticaria, commonly known as hives. This skin condition is characterized by raised, itchy welts that can appear suddenly in response to an allergen. Urticaria occurs due to the release of histamine and other mediators from mast cells and basophils, which is a hallmark of an allergic reaction. This release leads to increased vascular permeability and stimulates sensory nerves, causing the characteristic itching and swelling.

While other symptoms such as bradycardia, hypertension, and diarrhea can occur in various clinical scenarios, they are not directly indicative of hypersensitivity reactions. For example, bradycardia may describe a response associated with certain neurological or cardiac conditions, hypertension could arise from numerous systemic issues, and diarrhea can result from gastrointestinal disturbances or infections. However, urticaria specifically aligns with the immediate immune response typical of hypersensitivity, making it the clear manifestation to expect in such cases.