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Medication/vaccine testing helps us to determine if your child is allergic to some medications and vaccines. If your child had a serious reaction to a medication or vaccine, your allergist may want to perform this test to see if your child is allergic.

  • One week before testing: Stop giving your child antihistamines, which can interfere with the challenge results.
  • Three days before testing: Stop giving your child cold medication such as Benadryl.

If you are unsure what medicines contain antihistamines or unable to stop a medication, please contact 617-355-6117 and ask to speak with an allergy nurse.

What happens during the medicine and vaccine test?

Your child is tested for an allergy to a medication or vaccine. There are several stages of testing, with 15 to 20 minutes between each stage. During these stages, the following tests are performed:

  • A skin prick test: An allergy nurse places drops of liquid onto your child’s arm or back, and presses the liquid into the skin with an applicator.
  • A needle test (intradermal): An allergy nurse uses tiny needles to inject a small amount of the medication or vaccine under the top layer of skin on the upper arm.

During each stage, the allergy nurse carefully watches for an allergic reaction, which is most often a small red bump that may feel itchy at the sight of injection.

What if my child has a reaction to the medication and vaccine test?

When your child has a positive reaction, your child is considered allergic to that medication or vaccine. These reactions usually go away in 30 to 60 minutes.

Your child may have swelling and itching at the injection site four to eight hours after the test. You may use an over-the-counter hydrocortisone cream to help with this.

Your child may have a skin reaction, called a delayed local skin reaction, at the injection site several hours after the test is performed. This reaction is typically not serious and should go away during the next two to three days. If you are concerned, call 617-355-6117 and ask to speak with an allergy nurse.

When will I learn the medication and vaccine test results?

The allergist or nurse tells you the results of the test before you leave. Your primary allergist discusses the next step or the plan of care with you at a follow-up visit or on a telephone call with you.

Will my child be given medication?

If your child tested negative to the vaccine, a medication challenge may be done. A dose of the medication will be given, and your child will be watched for 60 minutes.