Food Allergy

Food Allergy occurs when our body has mistaken a component of normal foods as a foreign pathogen, and mounts an immune response leading to a number of symptoms1. The hypersensitivity reactions (allergy) can cause harm and danger to us. Allergen is the substance present in food that causes a hypersensitivity reaction in a sensitised person. The most common food allergens in children are cow’s milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soybean and certain food additives.

Comprehensive clinical assessment, including history of allergy and food intake and tests for allergy are necessary to diagnose food allergy2,3.

Common Food Allergies in Infancy and Young Children

Cow's milk is the most commonly seen allergenic food in infancy, and it is often the earliest allergy being identified. The allergen involved in the allergic reaction is cow's milk protein. It usually affects skin and digestive tract. Immediate reactions happened after ingestion include rash, swelling, diarrhoea, vomiting. Severe reactions include blood in stool.

Babies will not be allergic to their mother’s milk but may react to allergens that pass through milk from the mother’s diet. If the baby is showing signs of allergy and being exclusively breastfed, then the mother’s diet should be assessed and adjusted accordingly2.

Extensively hydrolysed formula and Elemental formula are suitable choices for infants who have cow’s milk allergy; where partially hydrolysed milk-based formula and soy-based formula are not suitable2,4. Healthcare professionals should first carefully investigate infant’s allergic symptoms, dietary intake, as well as family history before making diagnosis and giving clinical advice. Recent clinical guidelines for diagnosis and management of food allergies do not recommend using soy-based formula as a strategy for food allergy prevention in high-risk infants1.

Egg allergy is another common food allergy in children, especially in children younger than 2 years of age. Symptoms of egg allergy include rash, face swelling, diarrhoea, vomiting and difficult breathing2.People who are confirmed to be allergic to egg should avoid all eggs and food products contain eggs.

Children might develop tolerance to the allergic food and outgrow the allergy to milk and egg with time. Cohort study indicated that about 50% of children who were allergic to cow’s milk outgrew their allergy by the age of 66 months5; another study reported 80% of cow’s milk allergy disappeared when children turned 16 years old6. Similar observations seen in children with egg allergy. 50% of them outgrew their allergy by the age of 67,8.

Dietary management and advice

Avoidance of the allergic foods in all its forms is important to prevent the unwanted reactions. Parents and carers of the affected child need to understand and carefully identify origins and sources of allergens and thus avoid providing the culprit food to them. Take cow’s milk allergy and egg allergy as examples, there are countless prepared foods contain milk and eggs; such as cake, bread, mayonnaise and the majority of western desserts. Reading food labels about the food ingredients and whether they contain allergy warning is critically important for those affected by food allergy. Check out the Tips (see the last section) for some handy information on food labels.

Effective management of food allergy requires accurate assessment and diagnosis, detailed dietary planning and risk management. Seek registered dieticians for comprehensive dietary care plan. Below are important elements you might need to consider in managing food allergy:

  1. Accurate identification of the foods responsible for the symptoms

    Minimise unnecessary food restriction, especially in children for they have relatively high nutritional demands for growth and development. Only eliminate the culprit food from the diet. Unnecessary food avoidance can compromise one’s nutritional status and over restriction affects one’s quality of life including the social aspect.

  2. Ensure adequate nutrition and balanced diet

    The diet plan should be complete balanced nutrition from alternative sources or nutritional supplementation.

  3. Avoid cross-contact (also known as cross-contamination)

    Cross-contact occurs when an allergen is transferred from one food containing an allergen to another food that does not contain the allergen. Pay extra attention to prepared foods. Does the same production line for the food also produces foods containing allergen you need to avoid? Carefully read the food label. Also, when dining out, whether the cutleries provided and cooking processes at the restaurant are allergen-free?

The diet plan has to be personalised; taking lifestyle and personal habit into consideration to make it practical and efficient.

In caring children with food allergy, regular medical review is important to assess children’s growth and nutritional status. The dietary plan should also be reviewed and updated from time to time so that the parents can provide appropriate, nutritious, balanced and diversified diet to meet their children’s needs. Once the kid starts school, good communication among healthcare professionals, home, carers and school are essential to allow the school staff to make special arrangement on catering and provide corresponding support to reduce the risk of allergic reaction.


Accurate identification of food allergens from food labels, especially those hidden in processed foods:

Cow's milk allergy Food items which are likely to contain cow's milk* Ingredients which contain cow's milk*
Milk powder, milk beverage, yogurt,ice-cream, cream, butter, cheese, pudding, cake, chocolate, cream soup... Casein, caseinate, skimmed milk, skimmed milk powder, milk solid...
Egg allergy Food items which are likely to contain egg* Ingredients which contain egg*
Egg, mousses, mayonnaise, ice-cream, cake, egg pudding, some of the bakery products, egg noodle, egg roll... Egg white, egg yolk, egg liquid

* The lists are not exhaustive.

Useful links


  1. Boyce JA, Assa’ad A, Burks AW, et al (2010). Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clinical Immunol; 126(6):S1-S58.
  2. Janice Vickerstaff Joneja. The Health Professional’s Guide to Food Allergies and Intolerances. USA: Academy of Nutrition and Dietetics, 2013.
  3. The Association of UK Dietitians (2014) Food Allergy and Intolerance Testing. Access online: ( 15 Sep 2015)
  4. The Association of UK Dietitians (2012) Suitable Milks for Children with Cow’s Milk Allergy. Access online:
  5. Wood RA, Sicherer SH, Vickery BP et al (2013). The natural history of milk allergy in an observational cohort. J Allergy Clin Immunol; 131(3):805-12.
  6. Skripak JM, Matsui EC, Mudd K, Wood RA (2007). The Natural history of IgE-mediated cow’s milk allergy. J Allergy Clin Immunol; 120(5):1172-1177.
  7. Peters RL, Dharmage SC, Gurrin LC et al (2014). The natural history and clinical predictors of egg allergy in the first 2 years of life: a prospective, population-based cohort study. J Allergy Clin Immunol; 133(2):485-91.
  8. Sicherer SH, Wood RA, Vickery BP et al (2014). The natural history of egg allergy in an observational cohort. J Allergy Clin Immunol; 133(2):492-9.