Skin Prick Testing
Your child has an appointment for a skin prick test.
What is a skin prick test?
A skin prick test (SPT) is a way to test specific substances to see if they can potentially cause an allergic reaction. We perform skin prick testing for a range of common foods and aeroallergens (inhaled/airborne allergens).
How do we do a SPT?
The nurse will ask you to place your child on your lap (if an infant) or your child can sit on their own. The nurse will then draw circles on your child’s forearm or upper back with a washable ink pen. A small drop of allergen solution will then be placed onto the skin inside each circle, and the skin will then be pricked through the drop of allergen with a small metal lancet, allowing some of the allergen to go under the skin’s surface.
The drops that are left on the skin will then be blotted away.
If the test is positive, the skin will become red with a blister-like ‘wheal/hive’ in the centre, and it may be itchy. A positive result will be visible after 15 minutes and the nurse will then need to measure the result with a small ruler. The result will tell us how likely your child is to react to each allergen.
This form of testing is quite safe as only a tiny amount of allergen is introduced into the skin. We can also perform a test called a prick-to-prick test, so your nurse may ask you to bring a small piece of a specific food with you to the appointment.
Preparing for the test
If your child takes short-acting antihistamines, such as Chlorphenamine (Piriton®), they should stop taking them three days before the appointment.
If your child takes long-acting antihistamine, such as Cetirizine (Piriteze® or Benadryl®) Loratadine (Claratin®) or Fexofenadine (Telfast® or Allegra®) they should stop taking them five days before the test.
If your child suffers from eczema, do not apply any moisturisers to their arms on the day of the test and do not use any creams containing hydrocortisone/steroid for 48 hours before the test on the child’s forearms.
When do I get the results?
Once the nurse has measured the reactions, the results are available straight away. The nurse will discuss the results with you before you leave, or if you are seeing a consultant in clinic, they may also discuss the results with you. You will be able to give your child antihistamine as soon as the test is complete to relieve the itch.
Contact the nurse if
- Your child has had antihistamines within 72hrs of the test
- Your child is unwell
- Your child has had a flare up of their eczema/asthma.
Contact numbers
We hope that you have found this information useful. If you have any questions or are worried about anything, please speak to the following Dorset County Hospital staff:
Allergy Nurse Specialist: Juliet Lyus 01305 254279
Consultant: Dr Wylie (Secretary): 01305 253331
Consultant: Dr Newman (Secretary): 01305 253331
Feedback
If you would like to give us feedback on our Paediatric Community or Specialist Nursing Service, please complete our patient related experience survey: https://dchft.onlinesurveys.ac.uk/paediatric-specialist-and-community-nurses-questionnaire
All responses will be treated anonymously and in the strictest confidence and only used to help us improve our service for patients.
Useful websites
About this leaflet
Author: Juliet Lyus, Paediatric Allergy Nurse Specialist
Written: December 2022
Approved: May 2023
Review date: May 2026
Edition: v1
If you have feedback regarding the accuracy of the information contained in this leaflet, or if you would like a list of references used to develop this leaflet, please email patientinformation.leaflets@dchft.nhs.uk
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