Egg Allergy
Authored by Dr.Ramya Smitha
Introduction Egg is one of the most common allergy causing foods in children. The symptoms of egg allergy occur usually after a few minutes to a few hours after the consumption of eggs or egg containing foods. The signs and symptoms may be mild to severe which include skin rash, nasal congestion, vomiting, hives and other digestive problems. It can rarely causes anaphylaxis or life threatening reaction.
Egg allergy can occur from the infancy of a child, but most children outgrow their allergy to egg before reaching adolescence.
Causes Food allergies are caused due to an over reaction of the body’s immune system to that particular food. In egg allergy, the immune system mistakes the proteins in egg as harmful. When the person consumes eggs or any food item containing egg, the antibodies in the immune system identify the proteins and send a signal to immune system which releases histamine and other chemicals which cause allergic symptoms. Egg allergy is caused by both yolk and egg white as both of them contain proteins. Egg whites are more commonly known to cause egg allergy. It is also seen in the infants who are breast fed by mothers consuming eggs, as the egg proteins are also released in breast milk.
Symptoms The allergic reaction against eggs varies from one person to another. The symptoms include: • Skin rashes or hives: This is the most common allergic reaction in egg allergy. • Nasal congestion
Sneezing and runny nose • Digestive symptoms like nausea and vomiting, abdominal cramps • Asthma symptoms like wheezing, coughing, shortness of breath or chest tightness. Anaphylactic reaction: An anaphylactic reaction can be caused due to severe egg allergy. Anaphylaxis is a life threatening condition which requires and immediate epinephrine injection. The symptoms of anaphylaxis include: • Difficulty in breathing due to constriction of airways or swelling in throat • Abdominal cramps and pain • Rapid pulse • Shock with sudden drop in blood pressure which is felt as light headedness, dizziness or loss of consciousness. •
Diagnosis The physician takes the medical history and conducts a physical examination of the symptoms. Then the following tests may be recommended to diagnose egg allergy: • Skin prick test: In this test, the skin of the patient is pricked and exposed to a small quantity of proteins found in eggs. The person develops a rash or raised bump at the site of pricking if he/she is allergic to eggs. • Blood test: The blood test is done to check the presence of antibodies against egg proteins in the blood. • Re-challenge: In this test, the person who is allergic to eggs is given a small amount of egg to check the reaction. If there is no reaction, the quantity is increased and given again to check the symptoms of allergy. This test should be done by an allergy specialist as it can cause severe reaction. • Food tracking: This can be done by the patient or the physician. It includes maintenance of a dairy which contains the details of the allergy and food taken. This helps to determine the exact cause of food allergy.
Who are at Risk? The following factors can increase the risk of egg allergy in a person: • Family history: There is an increased risk of egg allergy if the person’s parents have food allergy, asthma or any other type of allergy such as hives, hay fever or eczema. • Atopic dermatitis: Children with this type of skin allergy are more prone to food allergies than children without skin problems. • Age: Infants and children are at greater risk of having egg allergy. With age the digestive system matures and lesser allergic food reactions occur.
Treatment Avoiding consumption of eggs or products is the only way to prevent egg allergy. However some people can tolerate eggs in well cooked foods such as baked foods. Antihistamines: Antihistamines may be prescribed by the physician to help reduce the signs and symptoms of a mild egg allergy. However these drugs are not effective in treating a severe allergic reaction. Epinephrine:
Emergency epinephrine injection is required for controlling the anaphylactic reaction caused in a severe egg allergy. The person is then kept under observation for some time to make sure that the symptoms don’t recur. Epinephrine autoinjectors should be carried by the persons who are severely allergic to eggs. One should make sure that the health care providers have access to the autoinjector in case of emergency or else if the child is old enough, he or she must have understanding of how to use the autoinjector. The autoinjector should be replaced before the expiry date.
Prevention The following tips should be followed to prevent egg allergy: • Check the labels on food items for presence of egg. • Be cautious when eating outside as the food provider may not know that you have egg allergy. • Children who have this allergy should be tied with an allergy bracelet or necklace so that the care givers will know what is going on in an emergency situation. • Breast feeding mothers should avoid eating eggs to prevent egg allergy in the infant. Hidden sources of egg products: Some of the food products which are labeled as egg-free may still contain trace amounts of egg in it. These food items include: • Marshmallows • Meringue • Mayonnaise • Breaded foods • Baked foods • Puddings • Custards • Frostings • Processed meat • Salad dressings • Many pastas