Which symptom is a key sign of anaphylactic shock?

Swelling of the tongue and lips is a key sign of anaphylactic shock because it indicates significant airway compromise that can lead to respiratory distress. Anaphylaxis is a severe allergic reaction that can occur rapidly after exposure to an allergen. During this reaction, the body releases a large amount of histamine and other inflammatory mediators, leading to vasodilation, increased vascular permeability, and effects on smooth muscle and mucosal swelling.

In the context of anaphylactic shock, the swelling of the tongue and lips occurs due to angioedema, which can result in difficulty breathing or swallowing. This swelling can obstruct the airway, making it a critical indicator that requires immediate intervention. Recognizing this sign is vital for emergency responders, as addressing airway obstruction promptly is a priority in anaphylactic emergencies.

While the other symptoms like rash, shortness of breath, and chest pain can also be observed in anaphylactic reactions, they may not be as specific or as urgent indicators as the swelling of the tongue and lips. The presence of these swellings signals an immediate threat to the airway, which distinguishes it as a critical sign in the recognition and management of anaphylaxis.