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, for example, 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 can 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. Few children are allergic to egg after the age of six, though in some cases this allergy can persist to adult life. 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. If there has been local skin swelling on contact with egg (especially raw egg) this can be very strongly suggestive. Children who have this problem will often refuse egg when it is offered to them.

Although egg allergy can also develop in adult life this is nearly always a condition that develops in infancy or early childhood. The symptoms in an egg allergic reaction 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 one of them. By the age of six or seven, most egg-allergic children can eat eggs again with impunity, and a new development of egg allergy after this age is uncommon.