Topics in Allergy
Eggs are common in our diet and are used in many ways. Egg is a customary ingredient in pastries, baked goods, some pastas, and sometimes unexpectedly is found in salad dressings, meatloaf recipes, or even liqueurs. Egg allergy is one of the most common food allergies in children. Fortunately it is also one of the most common to resolve itself over time. Reactions to egg can be mild to severe and even life threatening. Allergic reactions to egg most commonly involve the skin (flares of eczema or hives) or intestinal tract (cramps, vomiting, diarrhea).
Egg whites contain more allergenic proteins than egg yolk. Allergens from egg can be detected in breast milk of lactating women who have ingested egg and the larger the amount ingested, the larger the amount in human milk. Food allergy in children can predict the development of respiratory allergy. 55% of children with egg allergy eventually developed respiratory allergy problems.
Egg allergy is typically diagnosed by the history (development of allergic symptoms soon after eating eggs) and by allergy skin tests and/or blood tests (RAST test) to egg protein. At times an in office challenge with egg needs to be done to confirm the egg allergy. The exact combination of tests & challenges needed to diagnose an egg allergy varies with each patient's history.
Two thirds of egg allergic infants tolerate eggs by age seven. Children who have mainly skin or intestinal symptoms rather than respiratory symptoms or systemic anaphylaxis are more likely to outgrow egg allergies.
People allergic to chicken eggs frequently also react to other avian eggs (duck, turkey, goose, etc). Most egg allergic people do not react to chicken meat or to chicken feathers but both have been reported. Interestingly, people allergic to chicken meat are usually not allergic to eggs but often react to many avian meats. Some people react to eggs when they are raw or minimally cooked but do not react to well cooked eggs. Heat changes the structure of the allergenic protein so that it is not recognized as an allergen.
Questions have been raised about the safety of giving MMR (measles, mumps, rubella) vaccines to people with egg allergies. In the past skin testing has been done and the vaccine was given according to skin test results.
After a review of this subject James (NEJM-3322:1262-1266, 1995) recommended a revision of MMR vaccine recommendations in egg allergic individuals.
In one study 410 children with egg allergy were given a single dose of MMR vaccine. 4 minor reactions occurred, none requiring treatment.
In another study 54 children with egg allergy were given a single dose of MMR vaccine. No reactions occurred.
In a search of the medical literature 1209 children with egg allergy were given a single dose of MMR vaccine. 99.75% had no reaction.
Graded doses of vaccine administration were felt to possibly cause more reaction than administration in a single dose.
Current recommendations about MMR administration in egg allergic individuals:
1. MMR testing does not need to be done even with a history of egg allergy.
2. One injection rather than a graded series of injections, followed by observation for 90 minutes is recommended.
If parents or the physician do not feel comfortable with this option, testing and graded administration of the vaccine can still be considered.
There is a question of vaccination for influenza when one is allergic to eggs. Influenza vaccinations including nasal vaccines contain detectable amounts of egg protein. This is similar to the issue of MMR vaccination in egg allergic people but there have been no large studies of this question. Anecdotal reports of testing and vaccination with influenza vaccine have been reported but more extensive data is lacking.
Though the risk of reaction to influenza vaccination in egg allergic patients appears to be low we are not currently giving influenza vaccine to egg allergic patients because of the lack of data. Antiviral agents such as symmetrel or relenza may be considered if exposure to influenza occurs. If influenza vaccination is essential testing and administration of the vaccine can be done but there is some risk to this procedure.
The FOOD ALLERGY NETWORK has additional and frequently updated information about sources of eggs in commercial foods.
Food Allergy Network
10400 Eaton Place, Suite 107
Fairfax, VA 22030-3179
703.691.3179 Fax 703.691.2713
If you do have an egg allergy you should carry an EpiPen and know how to use it. Caregivers also need to be instructed. Children can carry an EpiPen at school with a note from our office. EpiPens may be given through clothing. If the EpiPen is used, you need to be seen and observed in an emergency room. Reactions have recurred even 2-3 hours after the initial reaction seemed to be improving.
If you have an anaphylactic reaction to eggs, spit the food out of your mouth, rinse and spit with water or other liquid, and use the EpiPen. USE THE EPIPEN AT THE EARLIEST SIGN OF A REACTION. You should also consider going to an emergency room unless the reaction was very mild. Even then there is a risk it could recur. Do not go to a restroom or other private place to use the EpiPen. Notify someone you are having an allergic reaction, tell them you are giving yourself a shot, and ask them to call 911. Wearing your Medic Alert bracelet is important and lets emergency personnel know what is happening if you are unable to communicate with them.
Patients at risk of anaphylaxis to foods or other materials should avoid beta blocker medications (used for heart, blood pressure, and glaucoma problems) as these will block the effect of the EpiPen.
With these precautions of avoidance, Medic Alert bracelet and availability of EpiPen egg allergy is a manageable problem. Although there have been rare exceptions fatal reactions almost never occur when an EpiPen is available and used early in the event of a reaction. New treatments for egg and similar food allergies may be available within the next few years.