Dr Mark Rosenthal


Consultant in Paediatric Respiratory Medicine

also specialist in Food Allergies & Disorders of Sleep

A | A | A

T: 0207 351 8832

E: s.harvey@rbht.nhs.uk

A:The Royal Brompton Hospital, London, SW3 6NP

How to Test for an Allergy

Suspecting that your child has an allergy is not the same as knowing for sure. It is important to seek advice from a doctor before making any drastic decisions about your child’s diet or lifestyle. A private paediatrician in London can test for allergies and provide advice on avoiding any triggers


Blood Tests for Allergies One way we can test for allergies is to perform a blood test. Having a blood sample taken can be scary for a child, so it should only be done if we really need the information it can provide. A blood test could reveal how prone a child is to allergic reactions or confirm an allergy to a specific substance.


Skin Prick Tests Another option for allergy testing is the skin prick test. It can be less frightening for the child, but it is still uncomfortable as the aim is to trigger a small reaction in the skin. Your private paediatrician in London will usually want to test several allergens at once. These could include grass pollen, mould, dust mites, or any animals you keep at home, such as cats, dogs or rabbits.


During the test:

  1. A small drop of each potential allergen is placed on the child’s arm. The locations are marked with pen to ensure the cause of any reaction can be identified.
  2. The skin at each location is scratched with a fine point to allow the allergen into the body. It shouldn’t hurt and it is much less that your child would feel during a blood test
  3. After about quarter of an hour the skin is checked. A positive reaction would be a small red patch or bump.
  4. The bumps should go away within about half an hour. They may be a little itchy, but most children won’t find them too uncomfortable.


Allergy Test Results The results of these allergy tests can help your private paediatrician in London to confirm the presence of an allergy or to identify the cause. However, these tests don’t always tell the full story. About half of us will show a positive reaction to something during an allergy test, but it doesn’t always mean we’ll have the same reaction in everyday life. The doctor will take your child’s symptoms into account too before making a diagnosis.