What should be immediately done if a patient experiences an acute allergic reaction?

In the event of an acute allergic reaction, administering epinephrine is the critical and immediate response. This is because epinephrine acts quickly to counteract the life-threatening symptoms of anaphylaxis, such as difficulty breathing, swelling of the throat, and a rapid drop in blood pressure. It works by constricting blood vessels, which increases blood pressure, and by dilating the airways, which helps with breathing.

Oral antihistamines, while useful in managing less severe allergic reactions, are not effective in treating acute reactions that require immediate attention, as they take time to work and cannot reverse respiratory distress or cardiovascular collapse.

Monitoring vital signs is important but should occur after immediate interventions have been taken, as vital signs need to be assessed continuously in a stable situation rather than during an acute response.

Positioning the patient comfortably is also important, but it should not be the first action taken during a severe allergic reaction. Instead, the priority is to manage the life-threatening symptoms with epinephrine. This prompt action can significantly improve outcomes for the patient experiencing an acute allergic reaction.