What are the signs and symptoms of anaphylaxis?

Anaphylaxis is a severe and potentially life-threatening allergic reaction that requires immediate medical attention. The signs and symptoms of anaphylaxis primarily stem from the rapid release of histamines and other chemicals in response to an allergen. Difficulty in breathing is a critical symptom, often due to swelling in the airway or bronchoconstriction, which can severely impede airflow. Swelling of the face and lips, known as angioedema, is another hallmark symptom that can occur rapidly during an anaphylactic episode. Hives, or urticaria, are also common and present as itchy, raised welts on the skin, reflecting the body's systemic allergic response.

These symptoms are significant because they indicate a serious reaction that can escalate quickly, often necessitating emergency interventions such as epinephrine administration. Recognizing these signs promptly can be lifesaving, emphasizing the importance of immediate intervention when they occur. In contrast, the other options provided do not align with the classic presentation of anaphylaxis. While they may represent various other medical conditions or mild allergic responses, they lack the immediacy and severity associated with anaphylaxis.