What are the most common signs and symptoms of anaphylaxis?

Anaphylaxis is a severe, life-threatening allergic reaction that can progress rapidly. One of the hallmark characteristics of anaphylaxis is the sudden onset of respiratory difficulties, which can include symptoms such as shortness of breath, wheezing, and throat swelling. This respiratory distress occurs due to airway constriction and inflammation.

Additionally, low blood pressure is a critical sign of anaphylaxis, often resulting from widespread vasodilation and increased vascular permeability, leading to a rapid decrease in circulating blood volume. This can cause dizziness, fainting, and even shock, making it vital to recognize and respond to these symptoms promptly.

While rash and swelling (such as urticaria or angioedema) can occur during anaphylactic reactions, they are not as universally critical as respiratory difficulties and low blood pressure, which directly indicate the severity and the potential fatality of the condition. Chest pain and arrhythmia, as well as fever and headache, are not typical signs seen specifically in anaphylaxis, making them less relevant in identifying this acute allergic response.