Which risk factor is commonly associated with allergic reactions?

The presence of a known drug or food allergy is a significant risk factor for allergic reactions. When individuals have a documented history of allergies, their immune systems have previously identified certain substances as harmful, leading to exaggerated reactions upon re-exposure. These reactions can manifest in various ways, such as hives, swelling, difficulty breathing, or even anaphylaxis, depending on the severity of the allergy and the amount of allergen encountered.

Other factors mentioned, such as recent surgery, frequent exercise, or travel to foreign countries, do not necessarily correlate with a higher propensity for allergic reactions. While each might contribute to a person’s overall health status, they are not directly linked to an increased risk of allergic responses as the history of known allergies is. Recognizing and understanding known allergens is crucial in managing and preventing potential allergic reactions effectively.