Egg Allergy

Introduction
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 it ?
Usually the reaction is either a generalised worsening of eczema within a short time after exposure to egg white. Sometimes there is also lip and tongue swelling and hives. Some children will only react to pure uncooked egg white such as found in mayonaise or egg flips. Severe anaphylaxis is very rare with egg allergy.

Most children with egg allergy will show a natural aversion to egg containing foods, finding the taste bitter or causing an unusual feeling such as tingling in the mouth.

Foods 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. Note that generally more exposure to egg will increase subsequent reactions.

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.

Avoidance

• 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 - For those who have had either a significant allergic reaction or strongly positive skin prick test then avoidance is important. Repeated exposure risks increasing subsequent reactions to anaphylaxis levels. 

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.