Eggs and Allergy
Why are eggs a cause of food allergy?
Some foods are more liable than others to provoke allergic reactions because of the kind of proteins they contain. The size of the protein molecule can be important and some proteins are more digestible, absorbable and stable than others. Eggs contain proteins that, in the raw state, are of the right size and stability to cause allergies, but in most cases cannot withstand the effect of heat. This explains why people with a mild allergy to eggs may tolerate some cooked foods, such as cakes or pasta, even when they contain relatively large quantities of egg.
When am I most likely to get an egg allergy?
Egg allergy is most common in infants under the age of twelve months and then becomes progressively less of a problem. It is estimated to affect between 1.5%-3% of infants. Half the children who have it will grow out of it by the age of three and few children are allergic to egg after the age of six, though in some cases this allergy can persist to adult life. A recent analysis* found that only 0.2% of adults in the UK are sensitive to eggs. Those with other allergies or with a family history of allergy seem to be particularly vulnerable.
How do I know if it's eggs that I'm allergic to? In infants and small children the development of an egg allergy can be dramatic. The most common way in which this allergy presents itself is with a red rash around the mouth within seconds of eating an egg, followed in a few minutes by swelling around the mouth, on the face, and also inside the mouth. A few babies develop vomiting, though loose stools are relatively uncommon. Later, further areas of skin swelling or eczema can occur, together with features such as wheezing, sneezing, or running of the eyes. Local skin swelling on contact with egg (especially raw egg) is also very strongly suggestive of egg allergy. Children who have this problem will often refuse egg when it is offered to them.
Egg allergy can also develop in adult life. The symptoms in an adult can be similar to those seen in childhood, but particularly include skin swellings or eczema and asthma, which can develop more gradually.
Will I be allergic to eggs forever? Although there are some food allergies that tend to be life-long - such as allergy to peanuts - egg allergy is not usually one of them. By the age of six or seven, most egg-allergic children can eat eggs again with impunity and the emergence of an egg allergy after this age is uncommon. A recent analysis* found that only 0.2% of adults in the UK are sensitive to eggs.
It is important that if your child suffers from an allergy to eggs, you should seek the advice of your doctor or a registered dietitian before attempting to re-introduce eggs into their diet.
*Burney P, Summers C, Chinn S, Hooper R, van Ree R, Lidholm J, Prevalence and distribution of sensitization to foods in the European Community Respiratory Health Survey: a EuroPrevall analysis, European Journal of Allergy and Clinical Immunology, 10:1111, p.1398-9995