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Penicillin Allergy

Frequently Asked Questions

This document has been developed by ASCIA, the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand. ASCIA information is based on published literature and expert review, is not influenced by commercial organisations and is not intended to replace medical advice.

For patient or carer support contact Allergy & Anaphylaxis Australia or Allergy New Zealand

pdfASCIA PC Penicillin Allergy FAQ 2024120.62 KB

Q 1: What does a penicillin allergy label mean?

Many people are told that they have a penicillin allergy, or think that they have penicillin allergy, and are ‘labelled’ with a penicillin allergy in their medical record. A person might be incorrectly labelled with having a penicillin allergy when:

  • They have symptoms such as rash, itching, or stomach upset while taking penicillin. These symptoms may not be a true penicillin allergy and may be side effects of the medicine or caused by the illness itself (for example, a rash from a viral infection such as flu or glandular fever)
  • The person has a family member with possible penicillin allergy.
  • They have outgrown a penicillin allergy, but do not know this, and are still incorrectly labelled.

Studies have shown that up to nine in ten of these people do not have a true penicillin allergy. There are many types of penicillin antibiotics available and these are important for treating bacterial infections. It is important to find out if you have a true penicillin allergy, so that you can receive the best treatment when you have a bacterial infection.

Q 2: What are the benefits of penicillin allergy testing?

If you have been told you have a penicillin allergy in the past, talk to your healthcare provider about being tested to find out if you have a true allergy. These tests can include blood allergy tests, skin allergy tests and/or antibiotic challenge testing. Confirming whether you have a penicillin allergy is important so that you receive the most effective and efficient treatment of bacterial infections.

Having an incorrect penicillin allergy label can result in longer treatment times, increased risk of side effects, and higher healthcare costs.

Q 3: What happens if allergy tests show that you DO NOT have penicillin allergy?

If allergy testing shows that you do not have a penicillin allergy, you can be prescribed penicillin or related antibiotics in the future, to ensure effective and efficient treatment of bacterial infections.

Q 4: What happens if allergy tests show that you DO have penicillin allergy?

If a true penicillin allergy is diagnosed after testing:

  • Your doctor will advise you to avoid the penicillin you have tested positive to. A drug allergy specialist will tell you if you are able to safely take other types of penicillin. If you are allergic to all penicillins, other antibiotics will be prescribed for bacterial infections.
  • Your allergy should be recorded in hospital, doctor, and pharmacy records and uploaded to your My Health Record. You may also be advised to carry medical identification of your allergy.
  • Your doctor may provide you with an ASCIA Action Plan for Drug (Medication) Allergy.

© ASCIA 2024

Content updated June 2024

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