Emergency Medical Technician (EMT) Intermediate Practice Exam

Following exposure to an allergen, what indicates the individual will most likely experience a severe allergic reaction?

1. They are allergic to other substances

2. They were previously exposed and sensitized to the allergen

3. They are currently under medication

4. They show no initial symptoms

The correct answer is: They were previously exposed and sensitized to the allergen

An individual who has been previously exposed and sensitized to an allergen is at a significantly higher risk of experiencing a severe allergic reaction. Sensitization refers to the immune system's initial exposure to an allergen, which leads to the production of specific antibodies. Upon subsequent exposure, the immune system recognizes the allergen and mounts a stronger reaction. This process can result in a faster and more intense response, potentially leading to severe symptoms such as anaphylaxis. In contrast, an individual allergic to other substances does not necessarily imply a risk for severe reactions to a specific allergen. Likewise, being under medication may provide some level of management for allergic reactions, depending on the type of medication and its function. Finally, if no initial symptoms are present, this typically indicates a lower likelihood of a severe reaction at that moment, although it doesn't rule out the possibility entirely. Therefore, prior sensitization is the most crucial factor in predicting the severity of the allergic response.