Egg Allergy

Egg allergy is nearly always due to reaction against proteins in egg white. It is primarily a problem of infants and toddlers and is the most likely allergy to fade by the age of three. It is the most common food allergy if the infant has eczema. This article provides some background and discussion on egg allergy. Often infants will also display allergies to other foods, particularly cow’s milk protein and peanuts.


 

What is egg allergy ?

There are usually two types of reactions to egg.  egg allergy

  • The child has no history of eczema and has contact with egg, usually slightly undercooked as found in scrambled egg, or a runny boiled egg. Within a few minutes the lips tingle, become inflamed and there will be redness and inflammation around the mouth. Sometimes there maybe some coughing or spluttering. This can happen anytime after the introduction of solids and often the first time exposed to undercooked egg. Often the infant has been fine with egg found in baked goods.  Severe anaphylaxis is exceedingly rare with egg allergy.
  • The child has a history of eczema and in addition to some of the above the eczema will deteriorate over the ensuing 24 hours.

The most important part of the history is the timing of the reaction. These will occur minutes after egg ingestion, and sometimes will disappear quite quickly especially if given anti-histamines. When this reaction occurs it is often very useful to take a photo of the reaction.

Foods containing egg that cause reactions

Usually baby custard or scrambled egg are the first foods that will cause a reaction. Playing with egg cartons, licking a cake making spoon, sorbet and even ice cream can result in a reaction. The more egg is cooked, such as in baking the less likely there will be a reaction.

For those who are at risk of anaphylaxis from egg

Some infants and children remain highly allergic to eggs – even when baked. These children can react when in a kitchen where eggs have been cooked, coming into contact with the hands or lips of someone who has eaten or touched egg or using utensils involved in cooking egg. In these instances there are commercial egg replacers that can be used in baking. See below for more food information.

Diagnosing using Skin Prick testing

One of the most accurate ways of detecting egg allergy is through skin prick testing. The forearm has a drop of protein extract impregnated just under the skin and if there is the development of a small insect bite like mark then this is said to suggest allergy. This bite is called a weal.

If the diameter size of the weal is greater than 5mm then the infant/toddler is likely to have a slightly more significant reaction. If it is 3 -4 mm then the reaction is likely to be milder -such as mild dermatitis.

In the older child egg allergy is likely to be more significant if the weal is 7mm or greater.

If there is no reaction at all then it can be assumed there is no risk of IgE reactions. This is usually done along with other food proteins such as milk, soy, peanut.

These tests are generally safe and accurate and if done properly using appropriate distraction techniques are well tolerated by infants toddlers, and children. For those with positive skin prick tests they should be repeated every year to determine if the allergy has disappeared as mentioned.

Avoiding egg containing foods. 

Infants – During the first few months if breast fed then the Mother will need to avoid egg proteins. The strictness will depend a little on how severe the reaction is. As solids are introduced foods will need to be checked to ensure egg products are not included. This primarily means poorly cooked or raw egg white as found in mayonaise, meringue, quiche’s or undercooked eggs.

Toddlers – In many cases the reaction will only be to uncooked egg protein. Well cooked egg, as in baked goods, can often be tolerated.  For those infants and toddlers with mild allergic reactions there is some that continuing to give egg containing biscuits/cake etc will induce tolerance and increase the chances of ‘growing out of egg allergy’.

For those who have had either a significant allergic reaction, and/or moderate to severe eczema, repeated exposure risks increasing subsequent reactions to anaphylaxis levels. The following is a list of foods to be avoided

  • Foods where egg is a major ingredient
  • Boiled, poached, scrambled fried eggs
  • Quiches, spinach, egg bacon pie
  • Meringue, Macaroons,
  • Mayonaise, Bearnase, tartare sauces
  • Food where egg is a usual ingredient Baked goods – glazed breads pastries, doughnuts. waffles, pancakes, fried rice, egg noodles, Pad Thai, caesar salad. Precrumbed foods such as schnitzels, meatloaf and hamburgers.
  • Food where egg is a possible ingredient Ice creams, sorbets, spaghetti sauces, noodles, dips, dumplings, sausages, clear soups and white wine.
  • Risk of egg contamination Biscuits

Older children – As mentioned many children will grow out of egg allergy. But sometimes they will react to pure raw egg only. These children can generally tolerate the above foods.

Immunisations

There are two vaccines that contain egg protein

MMR – This is generally safe to be given to egg allergic infants at 12 months – this is because the vaccine is grown in chick embryos not the egg white

Influenza vaccine – Despite containing some egg protein there has not been any significant reactions after this vaccine.

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