What happens at a food challenge or supervised feed?
A food challenge or supervised feed is a test carried out in hospital to see if your child is able to eat a certain food.
Your child may have a food challenge or supervised feed if other allergy tests have not given us a clear answer about whether they have an allergy or not. In both tests, your child eats the food under hospital supervision in case they have an allergic reaction. If your child is having a food challenge, they will eat four or five doses of the food we are testing and this will last approximately five hours in total.
A supervised feed is a bit quicker, your child will only have one dose of the food and this test will take about two hours in total. Your child will need to eat a full portion of the food to ensure they are safe, and can continue to have the portions at least two or three times a week at home. The specialist you saw at your outpatient clinic appointment will discuss whether a food challenge or supervised feed is the right test for your child. If it is, you will be given the details to book an appointment for a challenge.
- safely find out if your child is able to eat a food
- eat a food which your child isn’t eating at the moment
- make your family’s life easier by:
- reducing the time you spend checking labels
- making eating outside the family home easier
- reducing the time you spend shopping
- reduce the worry of having an allergic reaction
- recognise the signs of an allergic reaction and how to treat i
Your child might have an allergic reaction during the test, which is why it is carried out in hospital.
Symptoms of an allergic reaction might include:
vomiting / sick
runny nose or eyes
life threatening anaphylaxis
Before you arrive It is really important that your child is well enough to have a food challenge or supervised feed for two reasons:
- if your child is unwell they might have a more severe allergic reaction
- if your child has any symptoms that are similar to an allergic reaction (such as a rash or runny nose), it may be difficult for us to tell if they are having an allergic reaction or not.
In the weeks leading up to your child’s test, make sure you check your child for signs of illness such as:
- rash or worse eczema
- runny nose, sneezing or a cough
- diarrhoea or vomiting.
If your child does not normally have these symptoms, but shows them in the week leading up to the test, please let us know. If your child has been in contact with someone who has had an infectious disease (such as chicken pox) within two weeks of the test, please let us know before you come. If you have any concerns about your child’s health before you come in for the test, you can phone our specialist nurses on 020 7188 9783.
Please make sure you know what food your child will be eating and bring it with you on the day of the test. You will need to bring the food with you in the form your child will eat it, for example if your child will be eating nuts, you may bring with you whole nuts, ground nuts or nut butters. You may also like to bring some other food with you to mix with the test food such as yogurt or fruit puree.
The allergy dietitians have developed some recipes for biscuits and cakes, which might make it easier for your child to eat the right amount of the food. If you would like a recipe and have not received one, please ask a member of the team.
The recipes are also available on the Evelina London website under Food Challenges on the Allergy Service page.
If your child is taking antihistamine medicine (e.g. Piriton©, Zitek© or Clarityn©), they will need to stop taking it before they come to the appointment as it may interfere with the results of the test.
Your child should stop taking short-acting antihistamines, such as Chlorphenamine (also known as Piriton©) two days before the test. Your child should stop taking long-acting antihistamines, such as Cetirizine and Loratidine (also known as Zirtek© and Clarityn©) five days before the test. Some cough and cold or travel sickness medicines contain antihistamines.
If you are unsure whether you can give these to your child before they come to the test, speak to your pharmacist or phone our specialist nurses on 020 7188 9783.
Your child does not need to stop taking any other medications (such as asthma inhalers or nasal sprays) before they come, but please bring a list of any medicines your child takes with you to the test. Please let the nursing team know if your child has needed to use their reliever (blue) inhaler. We may not be able to go ahead with the test, the nurses will discuss this with you and can then decide if it is safe for your child to continue with the test.
If your child has asthma, it is important that it is under control in order for them to do the test. If you think your child’s asthma is worse than usual in the week leading up to the test, please phone our specialist nurses on 020 7188 9783.
You should bring your child’s reliever inhaler to the test. It is fine for your child to use it if they need it, but please let the nurse know if you do. The nurse can then decide if it is safe for your child to continue with the test.
Arriving for the day
Your child will be asked to choose where they will sit for the day. Once you’ve settled in, one of our specialist nurses will talk to you and your child about what will happen during the day. You’ll be able to ask questions and go through any concerns that you have, then you’ll be asked to sign a consent form before we start the food challenge or supervised feed. Checking your child's health Before giving your child any food, a nurse will do some observations. This means they will listen to your child’s chest to hear their breathing and heartbeat. They will also place a probe on your child’s finger to record how fast their heart is beating, and how much oxygen is in their blood. It feels like a soft peg and won’t hurt but your child will need to keep still while we do this to get a clear measurement.
The food challenge
We’ll start by giving your child a very small amount of the food that you brought with you. We call this the first dose. After about 20 minutes the nurse will come back and check that your child has eaten all of the food and that they are not having an allergic reaction. If you or your child think that they are having an allergic reaction before the nurse comes to see you, just ask for them to come to you earlier. Your child might have their observations checked again.
If your child has eaten all of their first dose of food and not had an allergic reaction, they’ll be able to have their next dose. We’ll continue to give your child larger portions of food until they have eaten all the doses. Usually we give four or five doses of food and this will take about two hours. Once your child has eaten all of their doses of food, we’ll keep them on the day case unit for another two hours, to check for any signs of an allergic reaction.
If, at the end of those two hours, there is still no sign of a reaction, we will say your child is not allergic to that food and they will be able to eat it at home. If we find your child is not allergic to the food that has been tested, you should give this food to them at least three times each week. This is so their body will know that the food is something that should be eaten.
The supervised feed
A supervised feed is very similar to a food challenge however instead of several doses of the food we are testing, your child will have one dose, which is equivalent to a portion of that food, such as a glass of milk (200ml) or a handful of peanuts (15g). Your child will eat this dose slowly over 30 minutes and, once they have finished eating, will remain with us for one hour to check for any sign of an allergic reaction.
If, at the end of this time, there is no reaction, we will say your child is not allergic and they can eat that food at home. If we find your child is not allergic to the food, you should give this food to them at least three times each week. This is so their body will know that the food is something that should be eaten.
Your child might have an allergic reaction during their test and this is why we do the test in the hospital. If your child does have an allergic reaction, they will not have to eat any more of the food and they will be given medicine to stop it.
Allergic reactions usually cause a rash, itching, tummy ache or nausea but can sometimes make your child vomit (sick) or sneeze and have a runny nose. In rare cases your child may find it difficult to breathe but we will give them medicine straight away to stop this.
If your child has any allergic reaction they’ll need to stay at the hospital for longer, until they are well enough to go home, but not usually overnight.
If your child doesn't like the food they are trying
Lots of children find the taste of a new food strange, which is perfectly normal. You might like to hide the food in another that they do like to help them eat it. You could also bring some of your child’s favourite foods to eat after they have had their dose.
If you have any questions or concerns about food challenges or supervised feeds, please contact one of the children’s allergy nurses on 020 7188 9783 or 020 7188 3026 (Monday to Friday, 9am to 5pm) and ask for bleep number 1549.
If you would like to cancel or change your child’s appointment please telephone 020 7188 6390 to speak to the day case co-ordinator.
Leaflet number: 2166/VER2
Date published: January 2018
Review date: January 2021
© 2018 Guy’s and St Thomas’ NHS Foundation Trust
A list of sources is available on request