Which finding is indicative of an allergic reaction to medication?

An allergic reaction to medication is characterized by immune system responses that can manifest in a variety of ways. Among these, pruritus (itchiness) and urticaria (hives) are significant indicators. Pruritus arises from the release of histamines and other chemicals during an allergic response, causing an intense itching sensation. Urticaria, on the other hand, manifests as raised, itchy welts on the skin, which are classic signs of an allergy.

These symptoms indicate that the body is reacting to a substance it mistakenly identifies as harmful, leading to the activation of inflammatory pathways. This sets the allergic response in motion, which is specifically driven by the individual’s immune system.

Nausea and vomiting, increased heart rate, and respiratory depression can all occur for various reasons, including side effects of medications that are not necessarily related to an allergic reaction. For instance, nausea might result from gastrointestinal irritation or toxicity, while an increased heart rate could indicate anxiety, pain, or a variety of medical conditions. Respiratory depression is typically a concern with depressant medications and is not characteristic of an allergic reaction per se. Thus, pruritus and urticaria stand out as distinct markers of an allergic response.