A food allergy occurs when the immune system responds to an allergen (an ingredient that is usually harmless) in food. This triggers an immune reaction, which can range from mild to severe.

A severe allergic reaction (anaphylaxis) is a medical emergency. Call triple zero (000) immediately. Lay the person down. If they have an adrenaline injector and you are able to administer it, do so.

The majority of food allergies in children are not severe and usually children will outgrow many allergies with time. Some allergies, particularly nut and seafood allergies, are less likely to decrease with age.

A food allergy is different to a food intolerance. Food intolerances involve the digestive system, whilst food allergies involve the immune system. Most food intolerances don’t cause severe or life-threatening reactions.

What are the symptoms of food allergy?

Symptoms of a mild allergy include:

• hives (red circular weals on the skin)
• swelling of the face or around the mouth
• vomiting
• abdominal discomfort or pain

Symptoms of severe allergy may include:

• wheeze or trouble breathing
• difficulty talking more than a few words and/or a hoarse voice
• cough
• swelling or tightness of the throat
• collapse
• light-headedness or dizziness
• diarrhoea
• swelling of the tongue
• going pale and floppy (in young children)

What foods cause allergies?

Some foods are more likely to cause allergies than others. These include:

• dairy (including milk)
• eggs
• peanuts
• tree nuts (walnuts, almonds, pine nuts, brazil nuts and pecans)
• soy
• grains that contain gluten (wheat, barley, rye and oats)
• fish and shellfish

What are the tests for food allergies?

Skin or blood tests are used to find the triggers for food allergy. Sometimes a health professional will supervise a temporary elimination diet followed by food challenges to identify the cause.

Even if the tests show someone is allergic to a food, they cannot tell whether the reaction will be mild or severe. Sometimes people may test positive to an allergy to a certain food and be able to eat it with not symptoms.

There are several unproven tests for food allergy, such as cytotoxic food testing, Vega testing, kinesiology and hair analysis. There are not scientifically proven and should be avoided.

How is food allergy treated?

Food allergy should be managed under the guidance of a clinical immunologist or allergy specialist.

In most cases, the person must avoid the food they are allergic to. This means carefully reading food labels, taking care when eating out and avoiding cross contamination when preparing food.

They should carry their adrenaline autoinjector and ASCIA Action Plan for Anaphylaxis with them at all times and know what to do when a reaction occurs.

The Australasian Society of Clinical Immunology and Allergy recommends that allergen immunotherapy should not yet be used for routine treatment of food allergy, although there is ongoing research in this area. For further information, visit the Choosing Wisely Australia website.