An immune system overreaction causes food allergies. For egg allergy, the immune system mistakenly identifies certain egg proteins as harmful. When you or your child comes in contact with egg proteins, immune system cells (antibodies) recognize them and signal the immune system to release histamine and other chemicals that cause allergic signs and symptoms.
Both egg yolks and egg whites contain proteins that can cause allergies, but allergy to egg whites is most common. It's possible for breast-fed infants to have an allergic reaction to egg proteins in breast milk if the mother consumes eggs.
Egg allergy reactions vary from person to person and usually occur soon after exposure to egg.
Egg allergy symptoms can include
Skin inflammation or hives — the most common egg allergy reaction
Nasal congestion, runny nose and sneezing (allergic rhinitis)
Digestive symptoms, such as cramps, nausea and vomiting
Asthma signs and symptoms such as coughing, wheezing,
chest tightness or shortness of breath
A severe allergic reaction can lead to anaphylaxis, a life-threatening emergency that requires an immediate epinephrine (adrenaline) shot and a trip to the emergency room.
Anaphylaxis signs and symptoms include
Constriction of airways, including a swollen throat or a lump in your throat that makes it difficult to breathe
Abdominal pain and cramping
Shock, with a severe drop in blood pressure felt as dizziness, lightheadedness or loss of consciousness