Egg allergy

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at May 7, 2016
StartDiseasesEgg allergy

Egg allergies are one of the most common childhood food allergies; fortunately, many kids will outgrow this dangerous allergy by the time they enter elementary school. 

Contents

Definition & Facts

Eggs are second only to milk as being the most common cause of food allergies. For most children, the protein in egg whites is the cause of allergic reactions, but for some, the protein in the yolks may cause problems as well. In both cases, the immune system views the egg protein as a harmful intruder and goes on the attack by releasing the chemical, histamine to fight off the intruder. According to the Asthma and Allergy Foundation of America, 1.3 percent of children in the U.S. have an egg allergy, and they must avoid all foods that contain any trace of eggs. 

Symptoms & Complaints

Allergic reactions to eggs can vary each time they occur, and the symptoms are similar to other allergies. The child will experience one or more of the following symptoms:

Since this is a food allergy, a child may also experience a stomach ache, vomiting, and diarrhea. Anaphylaxis is a more serious symptom that can develop from an allergic reaction to eggs. Signs of anaphylaxis include:

When a child has this life-threatening emergency, it is important that they get an epinephrine shot and be taken to an emergency room immediately. If a child has had an allergic reaction to the food they just had just eaten, the parent or caretaker should take note of what the child ate, then go to the doctor so that they can get a proper diagnosis. Children who are allergic to eggs are also likely to be allergic to other foods like milk or peanuts, have allergies to pet dander or pollen, and asthma, so these should be looked into as well. 

Causes

The protein in egg whites causes the majority of allergic reactions, but in some cases, the protein in egg yolks can also cause a reaction. Children with an egg allergy should avoid eating eggs and anything that uses eggs as an ingredient. If the child is allergic to egg whites, separating the egg whites from the egg yolk doesn’t work because the egg white cannot be completely separated from the egg yolk.

Helping a child avoid foods that use eggs as an ingredient can be a challenging task for parents because eggs are used in many common foods such as bread, pasta, cookies, salad dressings, meatballs, meatloaf, as well as egg substitute products. Children may be able to tolerate some of these foods if they have been heated for a long period of time, but there is no way to predict when an allergic reaction may happen.

Eggs may not be explicitly stated on an ingredient list, so parents should look for words like albumin, globulin, or ingredients that use the prefix ‘ovo’ like ovomucin or ovotransferrin, and avoid giving these foods to their child.

Diagnosis & Tests 

When a child has an egg allergy, they are not just allergic to chicken eggs, they can be allergic to all eggs including duck, turkey and quail. If a child develops any allergic reactions after eating eggs, then the parent should take them to an allergist where they can conduct some tests. The first test is a skin-prick test where the allergist will place liquid containing egg protein on the back or forearm, then prick the skin so that the liquid will get into the skin. If a raised, reddish spot appears within 20 minutes, then it may be an indication of an allergy.

The second test is a blood test where a blood sample is taken to a lab and tested for immunoglobulin E antibodies which cause the allergic reaction to egg protein. A final test is an oral food challenge where eggs are eaten, in the presence of the allergist, or removed from the diet to see if the allergy symptoms occur or disappear. 

Treatment & Therapy

It is easy to avoid eating regularly cooked eggs like scrambled eggs, but because eggs are a common ingredient in so many different kinds of foods, avoiding eggs, in general, is not so easy. Fortunately, the Food Allergen Labeling and Consumer Protection Act of 2004 requires the clear labeling of egg or egg product as an ingredient in packaged foods manufactured and sold in the U.S.

In the event of a child with an egg allergy accidentally eating eggs or an egg product, they can be given an antihistamine to relieve mild symptoms like itchy skin or a stuffy and runny nose. An allergist may also prescribe epinephrine that can be used with an autoinjector in the event the symptoms deteriorate into anaphylaxis. 

Prevention & Prophylaxis

In the majority of cases, a child will no longer have an egg allergy by the time they turn 16 years old, so it is rare for an adult to have this type of allergy. The best preventive measure a parent can take to prevent their child from having an allergic reaction to eggs is to help them avoid eggs and foods that contain eggs as an ingredient.

A parent should carefully read food labels and let their child’s school know that they have an egg allergy. They should also have their child wear a bracelet that identifies their child as having a food allergy, so in the event the child has a reaction that leads to anaphylaxis, people who are responding to the situation will know what to do.