Food allergy and intolerance

If you, or someone in your care, has a severe allergic reaction, call triple zero (000) for an ambulance. The person having the reaction should not stand or walk. Administer an adrenaline (epinephrine) injector (such as EpiPen® or Anapen®) into outer mid-thigh. Further doses of adrenaline may be given if no response after 5 minutes. Give adrenaline first, then asthma reliever puffer, if required.

Food allergy and intolerance are different

Food allergy and food intolerance are commonly confused, as symptoms of food intolerance occasionally resemble those of food allergy. However, food intolerance does not involve the immune system and does not cause severe allergic reactions (known as anaphylaxis). Food intolerance also does not show on allergy testing, and the Australiasian Society of Clinical Immunology and Allergy (ASCIA) advises against non evidence-based allergy tests.

Food intolerance can be a difficult concept to understand. Sometimes, substances within foods can increase the frequency and severity of migraine headaches, rashes (such as hives) or the stomach upset of irritable bowel.

For more information watch the animated video How Allergies Work on the ASCIA website.

Professional diagnosis of food allergy by a clinical immunology/allergy specialist is important.

Food allergy is increasing

Allergies are on the increase worldwide and food allergies have also become more common. Most allergies appear during the first year of life. Cow’s milk allergy is one of the most common in early childhood. Most children grow out of cow’s milk allergy before they start school.

More research is needed into the causes, diagnosis and treatment of food allergy.

Allergy can be inherited

Children who have one family member with allergic diseases (including asthma or eczema have a higher risk of developing allergy.

Most of the time, children with food allergy do not have parents with food allergy. However, if a family has one child with food allergy, their brothers and sisters are at a slightly higher risk of having food allergy themselves, although that risk is still relatively low.

Allergy is an immune response

Allergies are an overreaction of the body’s immune system to a protein. These proteins may be from:

• foods
• pollens
• house dust
• animal dander (includes fur, wool and pollens brought into the home by pets)
• moulds.

They are called allergens. The word allergy means that the immune system has responded to a usually harmless substance as if it were toxic.

Food intolerance is a chemical reaction

Food intolerance is a chemical reaction that some people have after eating or drinking some foods; it is not an immune response. Food intolerance has been associated with asthma, chronic fatigue syndrome and irritable bowel syndrome (IBS).

Symptoms of food allergy and intolerance

It can be difficult to tell the difference between the symptoms of food allergy and food intolerance. Usually, symptoms caused by food allergy develop very soon after consuming the food. While symptoms caused by food intolerance can be immediate, they may also take 12 to 24 hours to develop.

Food intolerance reactions are usually related to the amount of the food consumed. They may not occur until a certain amount (threshold level) of the food is eaten, but this amount varies for each person.

The symptoms of food allergy and intolerance can also be caused by other conditions, so it is important to see your doctor for a medical diagnosis.

Symptoms of food intolerance

Symptoms of food intolerance can include:

• nervousness
• tremor
• sweating
• palpitations
• rapid breathing
• headache, migraine
• diarrhoea
• burning sensations on the skin
• tightness across the face and chest
• breathing problems – asthma-like symptoms
• allergy-like reactions.

Symptoms of food allergy

The symptoms of mild to moderate food allergy include:

• swelling of lips, face, eyes
• hives or welts
• tingling mouth
• abdominal pain, vomiting – these are signs of anaphylaxis for insect allergy.

Signs of anaphylaxis (severe allergic reaction):

• difficult or noisy breathing
• swelling of tongue
• swelling or tightness in throat
• wheeze or persistent cough
• difficulty talking or hoarse voice
• persistent dizziness or collapse
• pale and floppy (young children).

Action plans for anaphylaxis are available at ASCIA Action, First Aid, Management, Travel and Treatment Plans and Guides.

Body parts affected by food allergy

Various sites on the body can be affected by an allergic reaction to food, including:

• swelling of the face, lips, eyes
• swelling of the tongue
• swelling or tightness in the throat
• stomach pains, vomiting – these are signs of anaphylaxis for insect allergy
• skin – rashes, such as hives (urticaria) or atopic dermatitis
• lungs – wheeze, cough, asthma (more common in children than adults).

Severe allergic reactions to foods can be life-threatening

Anaphylaxis is a severe allergic reaction that needs urgent medical attention. Foods (such as peanuts, tree nuts, seafood, wheat, milk and eggs), insect bites and stings and some medicines are the most common allergens that cause anaphylaxis.

Within minutes of exposure to the allergen, the person can have potentially life-threatening symptoms, which may include:

• difficult or noisy breathing
• swelling of tongue
• swelling or tightness in throat
• wheeze or persistent cough
• difficulty talking or hoarse voice
• persistent dizziness or collapse
• pale and floppy (young children).

Several factors can influence the severity of anaphylaxis, including exercise, heat, alcohol, the amount of food eaten, and how food is prepared and consumed.

Emergency treatment for severe allergic reactions (anaphylaxis)

To prevent severe injury or death, a person with anaphylaxis requires an injection of adrenaline (epinephrine) into the outer mid-thigh. They should not be allowed to stand or walk. Further doses may be given if there is no response after 5 minutes. Give adrenaline first, then asthma reliever puffer, if required.

People who are considered by their doctor to be at risk of anaphylaxis are prescribed an adrenaline injector (such as an EpiPen® or Anapen®), which contains a single fixed dose of adrenaline. These patients should also have an ASCIA Anaphylaxis Action Plan.

Adrenaline injectors are designed to be used by non-medical people, and are available directly from a pharmacy.

Causes of food allergy

Peanuts, tree nuts, eggs, cow’s milk, wheat, sesame, fish, shellfish and soy cause the majority of food allergic reactions. Peanut allergy is one of the most common allergies in older children as only approximately one in 4 children will outgrow peanut allergy.

Causes of food intolerance

The foods that tend to cause intolerance reactions in sensitive people include:

• dairy products, including milk, cheese and yoghurt
• chocolate
• eggs, particularly egg white
• flavour enhancers such as MSG (monosodium glutamate 621)
• food additives
• strawberries, citrus fruits and tomatoes
• wine, particularly red wine
• histamine and other amines in some foods.

Finding the allergen

When symptoms appear within a few minutes of eating the particular food, it makes pinpointing the allergen an easy task. However, if the cause is unknown, diagnostic tests may be needed, such as:

• keeping a food and symptoms diary to check for patterns
• under the supervision of a clinical immunology/allergy specialist or dietitian, removing all suspect foods for 2 weeks, then reintroducing them one at a time to test for reactions (except in cases of anaphylaxis)
• skin prick tests using food extracts or IgG blood tests.

ASCIA strongly recommends only having evidence-based allergy tests.

Treating food allergy or intolerance

The easiest way to treat a food allergy or intolerance is to eliminate the offending food/s from the diet. Sometimes, the body can tolerate the food if it is avoided for a time, then reintroduced in small doses, particularly for food intolerances.

Before you eliminate or reintroduce foods, seek advice from a clinical immunology/allergy specialist or dietitian.

Preventing food allergy in children

Allergy prevention in children is an active area of research. Findings to date indicate that:

• Prenatal – there is no conclusive evidence that avoiding allergens in pregnancy will help prevent allergies in your child.
• Postnatal – exclusive breastfeeding during the first 4 to 6 months appears to protect against the development of allergies in early childhood.
• Introducing solid foods (including those considered to be allergenic) around 6 months (but not before 4 months) is recommended, preferably while continuing to breastfeed.
• Breastfeeding – avoidance of a food (including foods considered to be highly allergenic) by a woman while breastfeeding is not recommended.
• Soymilk formula – studies have shown that using soymilk formula does not prevent the development of allergies in children.
• Partially hydrolysed cow’s milk-based formula (commonly referred to as HA formula) is not recommended to prevent the development of food allergy.

Severe food allergy in children

Allergic reactions, including anaphylaxis, are common, although deaths from anaphylaxis are rare. All schools and childcare services across Australia are required to have an anaphylaxis management policy in place. Teachers in every state are trained to recognise and react to an allergic reaction by completing ASCIA Anaphylaxis e-training. They should also practise using an adrenaline injector training device.

Banning particular foods in schools and early childcare is not recommended as it can create a sense of complacency and is difficult to monitor and enforce. A better approach is to educate staff, students and the community about the risks associated with anaphylaxis and put strategies in place to minimise exposure to known allergens. The Allergy Aware website has many resources available.

Food allergen avoidance

You should only avoid foods to which you have a diagnosed allergy. Learn the terms used to describe these foods on food labels, for example:

• milk protein – milk, non-fat milk solids, cheese, yoghurt, caseinates, whey, lactose
• lactose – milk, lactose
• egg – eggs, egg albumen, egg yolk, egg lecithin
• gluten – wheat, barley, rye, triticale, wheat bran, malt, oats, cornflour, oat bran
• soy – soybeans, hydrolysed vegetable protein, soy protein isolate, soy lecithin
• salicylates – strawberries, tomatoes.

The National Allergy Strategy has developed a resource hub to assist with best practice procedures for food allergen management.

Food laws and labels

Since December 2002, the Australia New Zealand Food Standards Code requires food labels to declare certain foods and certain substances in foods, including:

• cereals that contain gluten and gluten products
• shellfish and their products
• eggs and egg products
• fish and fish products
• milk and milk products
• tree nuts, sesame seeds and their products
• peanuts
• soybeans and their products
• added sulphites in concentrations of 10 mg/kg or more
• royal jelly (presented as food or present in food), bee pollen and propolis.

These foods must be declared if they are:

• used as an ingredient
• part of a compound ingredient
• a food additive or part of a food additive
• a processing aid or part of a processing aid.

Where to get help

• In an emergency, always call triple zero (000)
• Emergency department of your nearest hospital
• Your GP (doctor)
• NURSE-ON-CALL Tel. 1300 606 024 (24 hours, 7 days) – for health information and advice
• Australasian Society of Clinical Immunology and Allergy – Locate a specialist
• Allergy & Anaphylaxis Australia
• Dietitians Australia
• Nutrition Australia Tel. (03) 9650 5165