What is a common sign of an allergic reaction?

Swelling of the face or throat is a common sign of an allergic reaction, often referred to as angioedema. This swelling can occur suddenly after exposure to an allergen and may affect the lips, tongue, throat, and even the eyes. It is a serious symptom that can lead to difficulties in breathing and swallowing, indicating a potentially life-threatening condition known as anaphylaxis.

Recognizing this symptom is crucial for timely and effective intervention, as it can escalate rapidly. While other symptoms may arise in various medical conditions, the presence of swelling in these areas is particularly associated with allergic reactions and warrants immediate medical attention.