Which of the following is a symptom of anaphylaxis?

Anaphylaxis is a severe, potentially life-threatening allergic reaction that occurs rapidly after exposure to an allergen. One of the hallmark characteristics of anaphylaxis includes peripheral vasodilation, which leads to a significant drop in blood pressure and can cause symptoms of shock. Additionally, airway obstruction is a critical concern in anaphylaxis, as the swelling of the throat, due to angioedema or bronchospasm, can severely compromise the airway and hinder breathing.

The combination of these symptoms—peripheral vasodilation and airway obstruction—demonstrates the systemic nature of the reaction, affecting multiple organ systems. Recognizing these clinical signs is crucial for prompt intervention and can be life-saving.

Other options highlight symptoms that may not necessarily be associated with anaphylaxis. Increased heart rate alone, as mentioned in another option, can occur in many different conditions, including anxiety or other medical emergencies, but it does not encapsulate the full spectrum of anaphylaxis. Similarly, difficulty digesting food or conditions such as bone fractures and swelling do not reflect the acute and systemic response typical of an anaphylactic reaction.