The Australasian Society of Clinical Immunology and Allergy

Allergic reactions to soy, wheat and egg usually resolve by the time a child starts school. Unfortunately, reactions to seafood and nuts usually persist. A condition known as "Oral allergy syndrome" is most commonly observed for the first time in young adults.

Version 2 December 2000

Soy allergy is common in infants

Soy allergy is a common allergy of infancy, often first experienced when a baby is given soy milk formula because of known cows milk allergy. Around 1 in 5 children allergic to cows milk have problems with soy as well. Like cows milk, it is hard to avoid because it finds its way into so many processed foods, including:

• baked goods such as bread, batters, cereals, sausages
• as a binder in small goods
• in salads and canned beans

Soy lecithin is an emulsifier (322) found in many foods such as chocolate, margarine, and carob. Occasionally, very soy-sensitive subjects will have reactions to this as well. Other names for soy include soya, soy flour, soya protein, vegetable gum, textured vegetable protein, hydrolysed vegetable protein, lecithin, bean curd, soya bean paste (Miso, Tempe), and tofu.

Egg Allergy is very common in infants

Egg allergy is most common in infants less than 1 year of age. Up to 1 in 20 children may have a transient allergy to egg. Fortunately, around 80 % of egg allergy resolves by the time the child starts school. Use of terms such as egg yolk and egg white, albumen, egg powder or solids on the label may also indicate the presence of egg in a food.

Most people allergic to hens egg are also allergic to similar proteins in other bird eggs like duck, so these are best avoided as well. Cooked egg is sometimes better tolerated than raw egg, so some children with mild egg allergy seem to be able to tolerate small amounts in cakes or slices. Common foods containing egg include:

• malted drinks
• custards, mousse
• souffles, meringues
• glazed rolls or pastries
• cakes, slices and macaroons
• some soups and sauces (e.g. Hollandaise)
• rissoles or meat loaf (used as a binding agent)
• dessert mixes (waffles, pavlova mix, confectionery etc)

Seafood allergy is uncommon in children

Seafood allergy includes allergies to "scaly fish" (like cod, salmon, tuna or dory), to crustaceans (like crab, prawns or lobster) or molluscs (shellfish like oysters, clams). Seafood allergy is more common in adults than children. When it does occur, it usually remains as a life-long problem. Patients are usually allergic to 1 or 2 proteins that may be present in multiple species. Allergy to one fish often results in allergy to most other fish in the same way that allergy to one crustacean usually means that all must be avoided.

Allergy to wheat and cereals usually resolves within the first few years Allergic reactions to wheat and other cereals are most common in infants and usually resolve within the first few years of life. Whilst some children develop hives, other common symptoms are those of worsening atopic eczema. This usually occurs within a few hours of eating. Occasionally delayed reactions occur after the food is eaten regularly over several days, resulting in eczema or sometimes diarrhoea or poor weight gain. In this situation, skin allergy testing is often negative and the diagnosis rests on temporary elimination from the diet followed by deliberate challenge under careful medical supervision. Wheat and cereal allergy is occasionally seen for the first time in adults. Many suffer from grass pollen hayfever as well.

It is important to distinguish allergic reactions to wheat from coeliac disease or food intolerance associated with eating wheat products. These conditions are described in the article on Food Intolerance in this series.

Allergy to one meat usually means allergy to all meats

Meat is a major source of protein in Western diets, and allergic reactions to beef and chicken are the most common. Unfortunately, recent studies suggest that individuals allergic to one meat may have sensitivities to similar allergens present in multiple mammalian meats.

Reactions to other foods are less common

Allergic reactions to the above food groups (as well as milk, peanuts and tree nuts - described in other articles in this series) are the most common. Nevertheless, reactions to a diverse range of food and plant-derived products such as spices, vegetable gums, gelatine, herbal remedies (eg. Royal Jelly, Echinacea), vegetables and meats have all been described.

Oral Allergy Syndrome

About 1 in 10 people with allergy to some grass or tree pollens will complain that some uncooked vegetables or fresh fruits and nuts will make their mouth and throat itchy or swell. This is known as Oral Allergy Syndrome. In this condition, people are allergic to proteins that are present in pollens as well as these foods. If the food is heated, the protein is often destroyed. This is why they can usually eat the cooked food without a problem. More serious allergic reactions sometimes occur, particularly if exercise is undertaken soon after eating a lot of this type of food. Occasional unlucky people are allergic to many fruit and vegetables.

Allergic reactions to inhaled food are uncommon

Allergic reactions to food in the form of fine dust are uncommon, and mainly occur in food handlers. Examples include asthma induced by the fine dust of coffee or soy beans in processing plants, seafood allergens in some factories or wheat dust in bakeries. Sometimes people with severe food allergies find that even the smell of foods can trigger symptoms. Fortunately, this is a relatively rare complaint.

It is important to note that information contained in this bulletin is not intended to replace professional medical advice. Any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner.

References

1. Sampson HA. Food Allergy. J Allergy Clin Immunol 1999; 103: 717-28
2. Sampson HA. Food Allergy. J Allergy Clin Immunol 1999; 103: 981-9
3. Sampson HA et al. Fatal and near fatal anaphylactic reactions to food in children and adolescents. New England Journal of Medicine 1992; 327: 380-384
4. Vickers DW et al. Management of children with potential anaphylactic reactions in the community: a training package and proposal for good practice. Clin Exp Allergy 1997; 27: 898-903.
5. Committee Report from the Adverse Reactions to Food Committee of the American Academy of Allergy, Asthma and Immunology. Journal of Allergy and Clinical Immunology 1991; 87: 749-751.
6. Bernhisel-Broadbent J. Allergenic cross-reactivity of foods and characterisation of food allergens and extracts. Ann Allergy Asthma Immunol 1995; 75: 295-303
7. David TJ (ed). Food Allergy. J Royal Soc Med 1997; 90: 1-48.
8. Ayuso R et al. IgE antibody response to vertebrate meat proteins including vertebrate tropomyosin. Ann Allergy Asthma Immunol 1999; 83: 399-405.

Content Last updated 1 January 2000