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.
These are the most common test we do in our clinic. They help to tell us whether a child is at risk of an immediate allergy to the substance being tested.
If your child is taking antihistamine medicine (for example, Piriton©, Zitek© or Clarityn©) they will need to stop taking them before they come for their appointment as they might interfere with the test.
Skin tests are performed by our nurse specialists. Drops of allergen extract are placed on the child's forearm and then a small pin is pricked onto the skin. The test is not painful but may cause some itchiness. If the test is positive, then an itchy spot will appear after 20 minutes. The size of it is measured and recorded and then passed to the doctor to interpret.
Skin tests need expert interpretation to be useful. The diagnosis of an allergy needs both a careful consideration of the patient's symptoms as well as the test results.
Find out more in our Skin prick testing leaflet (PDF 89KB).
Sometimes we may need to do an allergy blood test, which can provide similar information. If your child wants us to, we can put anaesthetic cream on their skin. This will temporarily numb the skin and help to reduce the discomfort of the blood test.
These tests can help assess if a child has asthma and if they do, how well controlled it is. It involves blowing into a special tube, attached to a computer. Children aged under 6 usually find it too difficult to use this equipment.