Food Allergy - Frequently Asked Questions (FAQ)
Q 1: Why is food allergy increasing?
It is not understood why food allergy has increased in recent years.
Possible explanations include:
- Hygiene hypothesis, which proposes that less exposure to infections in early life, is associated with an increased chance of developing allergies.
- Delayed introduction of allergenic foods (beyond 12 months of age) such as egg, peanut or tree nuts.
- Methods of food processing, such as roasted versus boiled peanuts.
- Development of allergy to food by skin exposure, such as the use of food based moisturisers.
Q 2: If I have a positive allergy test, does this mean I am allergic to the food/s?
A positive food allergy test using skin tests or blood tests for allergen specific immunoglobulin E (IgE) antibodies, means that a person's immune system has produced an antibody response to that food. This is known as sensitisation.
It is possible to have sensitisation without allergy, which meants that the person can eat the food without any symptoms. For this reason, it can be important to confirm a positive allergy test with a food allergen challenge.
Q 3: Does cooking the food remove the allergen?
Cooked or baked foods, such as cow’s milk and/or egg in muffins, cakes or biscuits, may be tolerated by some people with allergy to cow’s milk and/or egg. Unless tolerance to cooked or baked foods is confirmed, this should be discussed with your clinical immunology/allergy specialist before introducing these foods.
Q 4: Are there any foods I should avoid feeding my child when solids are introduced?
No, there aren't any foods you should avoid feeding your infant. Solid foods should be given around six months of age but not before four months, and preferably whilst breastfeeding.
There is published evidence that for infants with severe eczema, and/or egg allergy, regular peanut intake before 12 months of age can reduce the chance of developing peanut allergy. If your child already has an egg or other food allergy, or severe eczema, you should discuss how to do this with your doctor.
It is important to note that infants differ in the age that they are developmentally ready for complementary solid foods. When your infant is ready, introduce foods in an age appropriate format, according to what the family usually eats, regardless of whether the food is thought to be a common food allergen. Raw egg is not recommended.
Some infants will develop food allergies. If there is any allergic reaction to any food, stop giving that food and seek advice from a doctor with experience in food allergy.
In children with confirmed cow's milk and soy allergy, appropriate formula is available on prescription from your doctor. Any dietary restrictions or modifications should be discussed and supervised by your doctor, who may also recommend you see a dietitian.
Q 5: If I can't breastfeed, which formula is useful in preventing allergies?
If an infant is not breastfed or is partially breastfed, commercial infant formula should be used until 12 months of age. In children with confirmed cow's milk and soy allergy, appropriate formula is available on prescription from your doctor. Any dietary restrictions or modifications should be discussed and supervised by your doctor, who may also recommend seeing a dietitian.
Based on a published review of studies, there is no evidence to support a protective role for partially hydrolysed formulas (usually labelled 'HA' or Hypoallergenic) or extensively hydrolysed formulas for the prevention of eczema, food allergy, asthma or allergic rhinitis.
Q 6: Are some formulas or other milks unsuitable for children with cow's milk allergy?
Yes. Children allergic to cow's milk are usually allergic to similar proteins in other animal milks, such as goat's milk. These products can also trigger allergic reactions, and should be avoided. You should discuss th use of other mammalian milks with your medical practitioner.
Milk labelled "A2 milk" is claimed to have a number of health promoting properties, but is unsuitable for cow's milk allergic children.
Partially hydrolysed cow's milk based formula is not suitable to be used as treatment for cow's milk allergic children.
Q 7: Are all reactions to milk due to allergy?
No. Lactose intolerance is caused by the lack of the enzyme lactase, which helps to digest the milk sugar lactose. The symptoms of lactose intolerance are diarrhoea, vomiting, stomach pain and gas, which are similar to some of the symptoms of milk allergy. This condition is uncomfortable but not dangerous, and does not cause symptoms of food allergy such as hives, swelling or anaphylaxis. In lactose intolerance, small amounts of cow's milk are usually tolerated, and yogurts and hard cheeses are usually tolerated better than milk, as they contain less or easier to digest lactose than cow's milk.
Q 8: Is immunotherapy (or desensitisation) available for food allergy?
Not yet. Whilst there are some trials of oral immunotherapy (OIT) for food allergy occurring in Australia, this is an area of ongoing research at this time.
Q 9: Are all food allergies severe?
No. The majority of food allergies are mild or moderate. Symptoms include hives, stomach upset or vomiting. However, symptoms such as difficulty breathing due to throat swelling or asthma, or dizziness due to a drop in blood pressure, indicate a potentially life threatening severe allergic reaction (anaphylaxis).
Q 10: Are allergic reactions to inhaled foods common?
No. Allergic reactions to food in the form of fine dust are uncommon. Most food proteins do not easily disperse as aerosols. Food handlers may have reactions to inhaled foods, including soy beans in processing plants, seafood allergens in some factories and wheat dust in bakeries. Foods which are more likely to cause an allergic reaction in the home environment in highly sensitised people include steam from cooking seafood and dried egg powder. Sometimes people with severe food allergies find that even the smell of foods can trigger symptoms, however, this does not happen often and symptoms are rarely dangerous.
Q 11: If I am allergic to peanuts or tree nuts, will I also be allergic to coconut?
Allergic reactions to peanut and tree nuts are relatively common, whilst allergic reactions to coconut are relatively rare. Some people with coconut allergy also have allergy to tree nuts such as walnut and hazelnut.
Q 12: Does having an allergy to one meat mean I will be allergic to all meats?
Meat is a major source of protein in Western diets, and allergic reactions to beef and chicken are rare food allergies but the most common of meat allergies. Recent studies suggest that individuals allergic to one meat may have sensitivities to similar allergens present in multiple mammalian meats. You should discuss the need to avoid all meats with your medical practitioner.
Q 13: Should schools and early childhood education/care centres ban foods?
Avoiding known allergens is the basis of food allergy and anaphylaxis management. A range of risk minimisation strategies should be taken and these will vary depending on whether it is a school or early childhood education/care centres, the possible routes of exposure to known allergens and the age of the child.
Restricting some important food allergens (such as nuts) may have a place in reducing the risk of accidental exposure in children who are too young to be relied upon to avoid contact with potential allergic triggers themselves, either by ingestion or cross contamination of toys or play equipment.
Blanket food bans or attempts to totally eliminate food allergens in schools and early childhood education/care centres are not recommended by ASCIA for the following reasons:
- It is not possible to guarantee complete removal of an allergen such as peanuts, regardless of policies.
- Food bans may give parents/carers and people with allergy a false sense of security.
- Children can be at risk of anaphylaxis from many foods, insect stings or bites. Therefore, it is not possible to ban all foods or insect allergens from a school or early childhood education/care centres.
- It is more important for schools and early childhood education/care centres to implement a range of age appropriate risk minimisation strategies and consider children with severe allergies when planning activities.
Q 14: Can I use a hand sanitiser to remove a food allergen from my hands?
No. The aim of hand washing is to remove allergens rather than disinfect. Soap and water are ideal, but if they are unavailable hand sanitiser wipes may be used.
Liquid sanitiser (not wipes) that is not rinsed off is not recommended as it does not remove the allergen.
Q 15: What is Pollen Food Syndrome?
Pollen food syndrome, also known as oral allergy syndrome, occurs mainly in people with allergic rhinitis (hay fever) who are sensitised to inhaled grass or tree pollens, which contain proteins that are present in certain foods. These allergens are known as cross reactive proteins. Pollen allergy usually develops before pollen food syndrome.
People with pollen food syndrome find that some uncooked vegetables, fresh fruits, spices and nuts will make their mouth and throat itchy or swell. If the food is cooked, the protein is usually destroyed, as the cross reactive proteins in pollens and foods are often quite fragile. This is why many people with pollen food syndrome can eat the cooked food without a problem.
It is rare to have severe allergic reactions (anaphylaxis), but some foods which commonly cause pollen food syndrome can also cause food allergy, and this can sometimes progress to anaphylaxis.
© ASCIA 2019
ASCIA is the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand.
ASCIA resources are based on published literature and expert review, however, they are not intended to replace medical advice. The content of ASCIA resources is not influenced by any commercial organisations.
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Updated May 2019