Allergy testing

Before your allergy test

We provide tests that cover all the common food and environmental allergens.

If you believe your child may be allergic to an unusual food or to a fruit or vegetable, then it's very helpful if you could bring these with you as we can use it to do an allergy test.

Please bring any medicines that your child is taking with you to the clinic. If your child has been referred because of a possible reaction to a medicine or anaesthetic, please bring along a summary of the medicines, which were given at the time of the reaction. This will help us plan the most appropriate tests.

It's important your child does not take antihistamines at least 4 days before the their skin test, as antihistamines may interfere with the results.

During the test

Allergy testing can slow the clinic appointments down (as time is needed for the tests to react). Your journey through our department may include time with our doctors, nurses and dieticians, with diagnostic skin tests for most children. Therefore, please allow at least 2 hours for your visit.

As well as skin tests, our specialist nurses may perform lung function tests, or take the opportunity to revise your asthma inhaler or epipen skills.

After the test

After the test, the results will be passed to the doctor who saw you and you'll have the opportunity to discuss them. If you need to, you'll also have the opportunity to talk to a specialist children's dietitian.

Types of tests

There are 3 types of allergy tests:

  • skin prick test
  • specific IgE blood tests (previously called RAST tests)
  • atopy patch tests

Your consultant will talk to you about which tests are most appropriate for your child.

The 3 allergy tests



Phone: 020 7188 3300

Opening hours: Monday to Friday, 9am to 5pm

How to find us

Otter outpatients
Second floor, staircase B, South Wing
St Thomas' Hospital
Westminster Bridge Road
London SE1 7EH

This department is only accessible via lift/staircase B.

Map of Second Floor, South Wing, St Thomas' Hospital