Which of the following might require immediate first aid intervention?

The situation involving a person experiencing a severe allergic reaction is critical and requires immediate first aid intervention due to the potential for life-threatening consequences. Severe allergic reactions, also known as anaphylaxis, can lead to rapid onset of airway obstruction, difficulty breathing, and cardiovascular collapse. If left untreated, the person's condition can deteriorate quickly, making it essential for first responders to act promptly to stabilize the individual.

In cases of severe allergic reactions, administering epinephrine (if available), calling emergency services, and monitoring the person’s condition are crucial steps in managing the emergency. The severity of the reaction necessitates immediate attention, whereas the other options, such as a minor scrape, a broken bone without visible injury, or a burn with blistering, while they may require care, do not present the same immediate life-threatening risk that characterizes anaphylaxis. Therefore, timely intervention in severe allergic reactions is paramount.