Which of the following is a standard initial treatment for severe allergic reactions?

The standard initial treatment for severe allergic reactions, particularly anaphylaxis, is the administration of epinephrine. Epinephrine works rapidly to counteract the effects of severe allergic reactions by causing vasoconstriction, bronchodilation, and reducing vascular permeability. This helps to stabilize the patient by increasing blood pressure, improving airflow to the lungs, and minimizing swelling. The quick action of epinephrine is critical in preventing potentially life-threatening complications associated with anaphylaxis.

Other treatments, while important in a comprehensive emergency management plan, are not the first line for severe allergic reactions. For example, administering glucagon is appropriate for certain cases of severe hypoglycemia or as a countermeasure against beta-blocker overdose but is not used for allergic reactions. Providing oxygen therapy is beneficial for patients experiencing respiratory distress, but it does not address the underlying anaphylactic process. Starting intravenous fluids may be necessary in cases of shock or significant fluid loss, but again, it does not resolve the immediate symptoms of anaphylaxis. Administering epinephrine remains the most crucial and time-sensitive intervention in a severe allergic reaction scenario.