Overview

This is a way of introducing 1 or more nuts into your diet in a gradual, and safe way. You will be guided to eat the nut, starting with a small amount, and increasing this step-by-step, to an average portion (30g, which is about a handful). This is sometimes called a ‘food challenge’.

We are offering this option, after your assessment, because the chance of you having a serious allergy to nuts is so low that it is safe to introduce the nut at home.

We are recommending that you introduce specific nuts from this list (your allergy specialist will advise you which ones, and please refer to your clinic letter if you are unsure):

• peanuts
• blanched peanuts
• almonds
• blanched almonds
• hazelnuts
• blanched hazelnuts
• cashew nuts
• pistachios
• Brazil nuts
• pecans
• walnuts
• macadamias

When and where to do the challenge

It is best to set aside some time for this food challenge. The challenge will take 2 to 3 hours, and you should be fully prepared before you begin.

You should avoid exercise for 2 hours before and 2 hours after the challenge.

You should do this challenge at home, in a relaxed atmosphere, and not at work or school.

Before you begin you should:

• make sure you are well on the day, without any illness
• make sure your eczema, hay fever and asthma are under good control (avoid doing the challenge if it is the time of year when you normally get hay fever)
• stop taking any antihistamines at least 3 days before you do the challenge
• pick a date when your family or friends are with you, so they can provide support if it is needed
• be free for 2 hours after you have finished the challenge
• not take any painkillers on the day of the challenge (including after the challenge). You can take paracetamol, but you should not take any non-steroidal anti-inflammatory drugs (NSAIDs), for example ibuprofen
• not drink any alcohol on the day of the challenge (including after the challenge)

Safety

During your allergy clinic visit, you will have been asked lots of questions, and had tests, to make sure your risk of nut allergy is low. This means it is safe enough for you to eat the nut at home, following these instructions.

If you have any questions about your home nut challenge, please speak to your allergy doctor, nurse or dietitian.

There is also advice on what to do if you have any unexpected symptoms. 

You should have some antihistamines ready.

What you will need

Buy a bag of nuts of 1 type (not a mixed selection). You will need at least 30g of nuts to complete the challenge. You can usually buy them from the baking aisle of a supermarket.

Do not use:

• roasted nuts
• nuts with skins
• flavoured nuts
• nuts coated in chocolate or yoghurt

All measurements are in centimetres (cms).

Type of nut	A small piece of nut with a ruler measuring in cm	1 whole nut	10g of nuts
Peanut			13 to 15 whole nuts
Hazelnut			About 12 whole nuts
Almond			About 8 whole nuts
Cashew nut			6 or 7 whole nuts
Macadamia			5 to 8 whole nuts
Pistachio			15 to 18 whole nuts (without shells)
Walnut			3 or 4 half-pieces of nuts
Pecan			5 to 9 half-pieces of nuts
Brazil nut			3 or 4 whole nuts

You can use a tablespoon to measure out the nuts. A tablespoon is about 10g of nuts.

Instructions for the challenge

If you are doing challenges for different types of nuts, they should be tried on separate days.

When you are eating the nut, chew it well before swallowing.

You can have water with the nut challenge, but you must not have any other foods until at least 2 hours after the challenge.

A tablespoon is about 10g of nuts. 

What to do if symptoms occur during the challenge

If you feel mild symptoms (such as itchy mouth, tongue or throat), stop eating the nuts and wait until the feeling has completely gone away.

You should then repeat the same dose before continuing. If the same symptoms occur again, you should stop the challenge.

If the symptoms become troublesome and you do not feel comfortable continuing, stop eating the nuts and take 1 antihistamine (such as 10mg of cetirizine or loratadine).

Based on our assessment, we do not expect you to have a serious allergic reaction to nuts.

If you have any reaction during your challenge, email [email protected] giving your full name, date of birth, and hospital number (if known).

Follow-up appointments

You might have another follow-up appointment with us if your allergy doctor thinks it’s necessary. We might also phone you to see if your home nut challenge was successful, and ask you to complete a questionnaire to tell us if it has been a helpful experience for you.