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Paediatric drug challenges

How we determine if a child is allergic to a specific medication
Drug Challenges

Why do a Drug Challenge?

It is sometimes presumed that a child has a particular drug allergy based on an experience or incident in the past.

It can be difficult to assess if this incident was actually as a result of an allergy or if the symptoms may in fact be from the disease/condition for which the patient had been receiving the drug.

Blood tests to confirm a diagnosis are limited to only a small amount of drugs and these blood tests sometimes do not detect an allergy even when it is present.

Therefore, the only definitive means to confirm allergy is to challenge the patient to the drug again.

These drug challenges can be safely carried out on Ward 11 at Wycombe Hospital.

Before the Test

A member of staff from Ward 11 will contact you by telephone to arrange a suitable date for the test and answer any of your questions. The test should take approximately 3 hours so please make suitable arrangements to allow for this.

There is no preparation required for the test, however it is important that your child is well and has not recently taken any allergy medication.

The challenge should NOT go ahead if:

  • The child has any upper respiratory symptoms
  • There is worsening of his or her asthma or eczema.

If any of the above applies please contact Ward 11 on 01494 425506 to arrange another date.

The day of the Test

You will need to be on Ward 11 at Wycombe Hospital by 9:30am on the date of the test. When you arrive your child will be allocated a bed and their vital signs (temperature, pulse etc.) will be taken. Their named nurse will introduce themselves to you.

They will be examined by a Doctor.

The test involves your child drinking gradually increasing doses of the medicine suspected of causing the reaction. In between and after the doses they will be observed for any signs or allergic reaction. (see over)

If by the end of the test there has been no reaction then they are not allergic to that drug.

Your GP and referring Doctor will be informed of the result of the test.

Signs of Allergic Reaction:

Mild-Moderate Allergic Reaction

  • Swollen lips, face or eyes
  • Itchy / tingling mouth
  • Hives or itchy skin rash
  • Abdominal pain or vomiting
  • Sudden change in behaviour

Stay with the child. Call for help. Give oral antihistamine if available

Severe – Life Threatening Allergic Reaction (ANAPHYLAXIS)

  • Persistent cough
  • Hoarse voice
  • Difficulty swallowing
  • Swollen tongue
  • Difficult / noisy breathing
  •  Wheeze
  • Persistent dizziness
  • Pale / floppy body
  • Sudden sleepiness

Keep child calm and still. Call for Emergency Help i.e. 999.
Give Adrenaline by autoinjector if available.