Preparing for a food challenge

A food challenge test is the best way to confirm a food allergy or to see if your child has outgrown a food allergy.

We begin by placing a very small (trace) amount on the lips, if no reactions are observed your child will be given increasing amounts of the food over a period of time until a standard portion size is eaten. If any reaction is seen the challenge will be stopped and appropriate medication given. 

Only one food can be tested at a time and challenge tests are always performed under close supervision of medically trained staff.

How long will a food challenge take?

A food challenge usually lasts approximately four to five hours, however it may take longer particularly if your child has difficulty eating the challenge food or has a reaction. It is therefore best to make provision for the entire day and make alternative arrangements for siblings to be collected from school. A parent will need to be present for the duration of the challenge.

What should I bring?

Please remember to bring the food to be 'challenged’ as specified in your appointment letter. Your child should have a light breakfast on the morning of their appointment and you may bring drinks, snacks or a packed lunch but please ensure that you only bring foods that your child has safely eaten before. 

No other foods are to be consumed in the early stages of the challenge. Your healthcare professional will advise regarding when your child may have snacks/lunch.

Feel free to bring any books, games or magazines for your child to entertain themselves. We also have many toys/activities that can be provided by our play specialists.

What happens after a food challenge?

If a reaction has occurred, a doctor will decide when your child is well enough to go home. Very rarely a child will experience a delayed reaction, this may include an eczema flare or gastrointestinal symptoms. You will be given information on how to respond to a delayed reaction prior to going home.

Antihistamines and other medication

Your child should STOP taking any antihistamine medicines five days prior to the food challenge. Antihistimines include:

  • Zirtek (Cetirizine)
  • Piriton (Chlorphenamine)
  • Clarityn (Loratidine)

Antihistamines can also be found in some cough medicines and ‘cold remedies’. These should also be stopped prior to the challenge. Please check the medicine label.

It is NOT necessary to stop asthma inhalers or nasal sprays that are regularly taken.

Please contact the allergy nurses if you require any further information prior to the challenge day:

Barnet Hospital: 020 8216 4906
Royal Free Hospital: 020 7830 2001