What are food allergies?

A food allergy is when your body's immune system reacts to a food that is normally harmless (known as an allergen). When this happens, your immune system responds to this food as if it were dangerous. The result is known as an allergic reaction.

Food allergies affect around 1 in 10 one-year-old children in Australia. Some allergic reactions are mild, but some can be severe and even life-threatening. If the reaction affects your breathing or your heart, this is called anaphylaxis.

The most common food allergies in children are to:

• tree nuts and/or peanuts
• dairy
• wheat
• soy
• egg
• seafood
• sesame

Remember that anything that you eat might trigger a food allergy. This includes things that you don't normally think of as food, such as herbal medicines or spices.

What are the differences between a food allergy and an intolerance?

A food intolerance is different to a food allergy, as it does not involve the body's immune system.

Food allergies always involve a reaction of the immune system. In contrast, food intolerances have several possible causes, including:

• an inability to digest or absorb a particular type of food
• sensitivity to an ingredient

Symptoms of food intolerances and food allergies can be similar, but food intolerances only rarely cause life-threatening symptoms.

A food intolerance will not show a positive result with an allergy test. Your doctor or dietitian can diagnose food intolerances with a temporary elimination diet — only do this under their supervision.

How do I know if my child has a food allergy?

If your child has symptoms of food allergy, ask their doctor if a food allergy or intolerance may be the cause.

Symptoms of mild to moderate food allergies in children include:

• swelling of their face, lips or eyes
• hives (a bumpy red rash) on their skin
• stomach pain
• vomiting

Signs of a severe food allergy (anaphylaxis) include:

• difficulty breathing or noisy breathing
• swollen tongue
• swelling or tightness in the throat
• difficulty talking or hoarse voice
• wheezing or coughing
• dizziness
• collapsing

Young children may also become pale and floppy.

It can sometimes be difficult to know if your baby or young child is experiencing a food allergy. They may have symptoms such as:

• eczema
• diarrhoea that lasts more than a few days (chronic diarrhoea)
• reflux
• a slower than expected rate of weight gain (failure to thrive)

When should my child see a doctor about food allergies?

If you are concerned that your child may be experiencing food allergies or if they are showing a food allergy symptom, see their doctor. Your child may be referred to an allergist, immunologist or paediatrician.

How are food allergies diagnosed?

If you think your child may have a food allergy, their doctor may recommend some tests. These could include:

• Skin prick testing — this tests for allergies by placing tiny amounts of the food on your child's arm and gently pricking it into the skin. The test is positive if a small, itchy lump appears on the arm within 20 minutes.
• Blood tests (allergen-specific IgE) — these check if your child's immune system has a response to a particular type of food as a sign of allergy. This is useful if your child is taking eczema or allergy medicines that affect the accuracy of a skin-prick test.

If you suspect your child may have a food allergy, it's important to see your doctor for a formal investigation and diagnosis. Do not remove foods from your child's diet without first speaking with your child's doctor. Unnecessarily avoiding foods can have a negative impact on your child's health and wellbeing. Find out more about allergy testing here.

How are allergic responses to food treated?

Food allergies are best treated by determining what foods your child is allergic to and being careful to avoid them. Even if you are very careful, there is always a risk that they could eat a food that they are allergic to by mistake. If they are at risk of severe food allergy (anaphylaxis), you should work with their doctor to create a personal ASCIA action plan for anaphylaxis.

What is an ASCIA action plan?

An ASCIA action plan guides you what to do if your child has an allergic reaction. This will normally include using an adrenaline autoinjector. If a doctor prescribes your child with an adrenaline autoinjector, they should carry it at all times, including at day care, school or when in the care of others.

Avoiding foods that trigger an allergic reaction

Once you know what foods your child is allergic to, they must avoid eating them. All carers (including school and day care staff and family members) should read and understand the allergy information on food labels. People who prepare food for your child must know about the foods that contain the ingredient to which they are allergic.

Adrenaline autoinjectors

Adrenaline autoinjectors are used to treat the symptoms of a severe allergic reaction (anaphylaxis). The medicine in an autoinjector is called adrenaline. Adrenaline works very quickly to reduce the signs of an allergic reaction, such as throat swelling and restricted airways.

There are 2 different brands of adrenaline autoinjectors available in Australia. Both brands have 2 types of devices:

• one autoinjector for adults
• another autoinjector for children who weigh between 15kg and 30kg, which contains a lower dose of adrenaline

Training devices are available to help you, your child and other caregivers learn how to use an adrenaline autoinjector.

If you need to use one in an emergency, but are not sure how, instructions are printed on the packaging of the device, as well as in every ASCIA action plan.

Treating other symptoms of food allergies

Food allergies can be related to other conditions such as eczema and asthma.

Avoiding triggers is the most important way to prevent allergic reactions. There are also treatments available that can help relieve related conditions, such as eczema and asthma. Keeping these related health conditions well-controlled can also reduce the chance of your child developing allergies and/or experiencing a severe allergic reaction.

You can discuss any symptoms that you think may be connected to your child's food allergies with their doctor. They can develop a plan to manage your child's symptoms.

Other treatments

Immunotherapy works by gradually introducing the body to very small amounts of the allergen under strict medical supervision. This can help the body develop tolerance to the allergen and reduce or prevent the chance of an allergic reaction.

Immunotherapy can be useful and effective for some types of allergies, but it isn't yet routinely used to treat food allergy in Australia. Ask your child's doctor if immunotherapy could be useful in managing their allergies.

Can allergic responses to food be prevented?

Children who have known allergies

The best way to prevent your child with food allergies from experiencing an allergic reaction is to help them avoid the foods that they are allergic to. If someone else cares for your child, make sure that they know about your child's food allergy and what to do in the event of an accidental exposure or allergic reaction.

Your child should have an ASCIA action plan.

You should also discuss with their day care facility or school ways to prevent accidental exposure to allergens. Staff should have training to recognise and respond in case of an allergic reaction, including knowing where your child's adrenaline autoinjectors are kept and how to use them.

Baby weaning and allergy prevention

Avoiding common allergens has not been shown to reduce the chance of your child developing a food allergy.

Introducing babies to foods that commonly cause allergies before their first birthday can reduce their risk of developing food allergies. This recommendation applies to all children, including those at a higher risk of developing food allergy, such as those with asthma, eczema or a family history of food allergies.

Use age-appropriate forms of common allergy-causing foods, such as well-cooked egg and smooth peanut butter.

Introduce new foods slowly. Only introduce one new food at a time. This way, if your baby has a reaction, you will know which new food they are reacting to.

If your baby has an allergic reaction to food, stop feeding them that food and see their doctor. Once a new food has been introduced, you should try to include it in your child's meals at least twice a week. Trying a new food but not eating it regularly can increase the chance of developing a food allergy.

Can my child outgrow food allergies?

Many children outgrow food allergies with time. This means that as your child grows up, they may stop being allergic to a particular food.

Your child is more likely to outgrow some allergies than others. For example, allergies to cow's milk, soy, wheat and egg are commonly outgrown by 5 years of age.

Allergies to peanuts, tree nuts, sesame seeds or seafood usually persist into adulthood, although around 1 in 4 children may outgrow them.

Resources and support

• Watch this video from Allergy & Anaphylaxis Australia to learn how to recognise signs and symptoms of an allergic reaction.
• Download "Jeremy's Cake", an interactive storytelling app designed to teach young children about their allergies.
• Manage your child's food allergies and share their ASCIA action plan on the Allergy Pal app.
• Learn more about the science of allergies in this short video produced by Allergy & Anaphylaxis Australia.
• Find out about starting a support group for parents of children with severe allergies on the Allergy & Anaphylaxis Australia website.
• Take part in an online training session on anaphylaxis and how to help people experiencing a severe allergic reaction, or recommend a training session to your child's school or day care centre.
• Learn more about preventing allergies when introducing your baby to foods on the Nip Allergies in the Bub website.
• Help your teenager to connect with other young people with food allergies via the Allergy 250k network.
• Watch a series of videos provided by the national allergy council to learn how to read food labels, handle and store food to minimize your child's allergy risk.