Food allergy basics

What is a food allergy? 

A food allergy occurs when a person’s immune systems reacts to a food protein that is harmless for most people. When eaten, the immune system releases large amounts of chemicals that trigger symptoms that can affect a person’s breathing, heart, skin and gut. 

Some food allergies can be severe, causing potentially life threatening allergic reactions known as anaphylaxis. 

Food allergy occurs in around 10% of infants, 4-8% of children aged up to 5 years and 2-3% of adults. 

90% of food reactions are caused by nine allergens: peanut, tree nuts, egg, cow’s milk products (dairy), sesame, shellfish, fish, soy and wheat.  However, any food has the potential to cause an allergic reaction. 

There is no cure for food allergy – therefore avoidance of the food is essential to prevent reactions. 

Is a food intolerance the same as food allergy?

No. A food intolerance does not involve the immune system. It is the inability to digest a food which can cause discomfort and distress, but is not life threatening.

Signs and symptoms of an allergic reaction to foods

ASCIA Action Plans provide information about when and how to give the adrenaline (epinephrine) autoinjector (e.g. EpiPen).  It is the go-to guide on how to manage an allergic reaction and should always be kept with the adrenaline autoinjector.

ASCIA Action plan anaphylaxis red personal 

MILD to MODERATE allergic reaction

Allergic reaction - man's back Allergic reaction on baby

SEVERE allergic reaction (anaphylaxis)

Watch for ANY ONE of the following

Severe allergic in a man

Anaphylaxis usually occurs within 20 minutes to 2 hours after exposure to the food. 

Mild to moderate signs may not always occur before anaphylaxis. 

This animation explains the signs and symptoms of an allergic reaction and what to do if someone has an allergic reaction.

Treating anaphylaxis

 It is important to lay the person flat – do not let them stand or walk.  If breathing is difficult, allow them to sit but not stand.

patient positioning for anaphylaxis

Prompt administration of adrenaline is the first-line treatment for anaphylaxis. Adrenaline (epinephrine) autoinjectors contain a single dose of adrenaline and have been designed so that anyone in the community can use them in an emergency.

How to administer an adrenaline autoinjector

More information about anaphylaxis is available from:

ASCIA website:

Allergy & Anaphylaxis Australia website:


Content updated July 2017