What common symptom may indicate the onset of anaphylaxis?

Swelling of the face or throat is a key symptom that can indicate the onset of anaphylaxis, a severe and potentially life-threatening allergic reaction. Anaphylaxis occurs rapidly after exposure to an allergen, and the swelling, known as angioedema, can cause airway obstruction, which is a critical aspect of this emergency. This swelling is often accompanied by other symptoms, such as difficulty breathing or wheezing, a rash, and gastrointestinal symptoms. The recognition of this symptom is crucial as immediate intervention is necessary to manage the airway and prevent further complications associated with anaphylaxis.

In contrast, while elevated heart rate can occur due to various conditions, it is not specific to anaphylaxis. A persistent cough may be associated with respiratory issues but does not specifically indicate anaphylaxis. A fever is generally more indicative of an infection and does not align with the immediate signs of an allergic reaction. Understanding the distinct nature of these symptoms helps in the timely identification and management of anaphylactic reactions.