What should be the first action taken in case of a severe allergic reaction?

In the event of a severe allergic reaction, commonly known as anaphylaxis, the most critical and immediate action is to use the person's epinephrine auto-injector if one is available. Epinephrine is a life-saving medication that rapidly counteracts the severe symptoms of anaphylaxis, including swelling, difficulty breathing, and a drop in blood pressure. By administering the auto-injector as soon as possible, you help stabilize the individual’s condition and prevent further progression of the allergy attack.

Using the auto-injector quickly is essential, as the effects of anaphylaxis can develop rapidly and become life-threatening within minutes. While calling emergency services is also an important step that follows the administration of epinephrine, immediate treatment with an auto-injector is crucial for reversing the severe symptoms. Other options, such as providing oral antihistamines, are not effective in treating anaphylaxis and should not be the first response. CPR is not relevant unless there is no breathing or pulse after the allergic reaction has progressed, which would indicate a different emergency situation.