What is a nut allergy?

If you are allergic to nuts, eating — or even just being exposed to — a small amount can trigger an allergic reaction. Nuts are one of the most common triggers for anaphylaxis — a severe reaction that can be life threatening.

A nut allergy develops when the body's immune system becomes over-sensitive to a protein in a nut. Being exposed to the nut causes an allergic reaction.

Nut allergies are becoming more common in Australia and can be very serious. About 1 in 5 children with a nut allergy will need emergency medical attention at some point. Very sensitive people can have a reaction if they are exposed to tiny traces of nuts: for example, through eating, breathing or simply touching a nut.

About 2 in 100 people have a nut allergy. Nut allergy is most common in infants and young children, but sometimes appears for the first time in adults. About 3 in 100 infants have a peanut allergy. About 1 in 5 of these will grow out of it, but the rest are likely to have peanut allergy into adulthood. About 1 in 3 people with nut allergy are allergic to both peanuts and tree nuts, such as almonds, macadamia nuts and cashews.

People can be allergic to different types of nuts. The most common ones are peanuts, almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pistachios and walnuts.

What causes nut allergy?

Children can become sensitised to nuts through breastmilk, close contact to people who eat a lot of nuts, or via skin massage with oils that contain nut protein.

What are the symptoms of nut allergy?

A mild reaction to nuts may cause the following symptoms:

• hives or welts
• swelling of face, lips and/or eyes
• vomiting, stomach pains or diarrhoea

Even if you usually only have a mild allergic reaction to nuts, you are still at risk of having anaphylaxis. Symptoms of anaphylaxis include:

• difficult/noisy breathing
• swollen tongue
• swollen, tight throat
• difficulty talking and/or hoarse voice
• wheezing or persistent coughing
• dizziness
• collapse
• becoming pale and floppy (young children)

Anaphylaxis is potentially life threatening and needs emergency medical treatment. You can read more about anaphylaxis on the ASCIA website.

How is nut allergy treated?

If you or your child has reacted to eating nuts, the first step is to see your doctor. They may send you to an allergy specialist who will do a skin or blood test to see what you are allergic to. You may be allergic to several different types of nuts.

There is no cure for nut allergy. The only proven treatment is to completely avoid exposure to the nuts you are allergic to. Research is underway into how to prevent nut allergies in people who may be at risk, and how to 'switch off' nut allergy using immunotherapy.

If you are at risk of anaphylaxis, you may be given an adrenaline autoinjector (EpiPen or Anapen). You should also have an anaphylaxis action plan so you and everyone else knows what to do if you are exposed to nuts.

Living with a nut allergy

If you are allergic to nuts, you must avoid any exposure to them, although it can be very hard to avoid all traces of nuts. ASCIA has a range of fact sheets with tips on avoiding different foods. In particular:

• Always read food labels.
• Take care with knives and forks, kitchen surfaces, barbecue plates, and shared butter and margarine that might be contaminated.
• Be careful when kissing or hugging someone who has eaten nuts (traces can stay on the hands, lips, teeth, beards and moustaches).
• Take extra care when eating out. Asian foods can be particularly risky, although nuts are also often used in pesto, salad dressings and many other foods, too.
• Always carry a supply of safe food with you when travelling.
• Be careful when eating other nut products — even if you do not think you are allergic to them. You are at increased risk of developing an allergy to a new nut.
• Always carry your adrenaline autoinjector (EpiPen or Anapen) with you.
• Tell others about your allergy and what to do if you are exposed to a nut.
• If in doubt, do not eat the food.

Children should take their own food to school and parties and should not share or swap food with other children. They may need to eat in a separate area from other children who are eating nuts.

More information

• Read more about peanut, tree nut and seed allergy on the ASCIA website.
• Get information on managing nut allergies from Allergy & Anaphylaxis Australia.