Allergic to antibiotics or fibbing?

Article published 11 August 2023

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Allergic to antibiotics or fibbing?

Most people who think they're allergic to first-line antibiotics are not. The consequences can be serious.

When hospitalised, one-in-four people in Australia say they have a penicillin allergy, but nine-in-ten who say this are wrong.

The consequences can be grave, because penicillin is used in first-line antibiotics, the most commonly used antibiotics.

Consequences of penicillin allergy

Saying you have a penicillin allergy means the hospital will not give first-line antibiotics to you.

Patients with reported penicillin allergies are given second- and third-line antibiotics, which contribute to antimicrobial resistance. This means every time you use them, your resistance to future infections is reduced.

Penicillin allergy, real or imagined, leads to poorer outcomes in hospital: longer stays, higher chances of infection with antibiotic-resistant ‘superbugs’, and higher mortality.

Studies show that most people with a self-reported penicillin allergy, are not allergic. When they are tested for penicillin allergy, they have no reaction.

“When you go to the trouble of skin testing and challenging people, around 90 per cent don’t actually have a penicillin allergy. One problem is it’s so much work to do all of that safely,” says Dr Winnie Tong, allergy researcher at UNSW Medicine & Health and clinical immunologist at St Vincent’s Hospital Sydney.

Why so many imagine they have a penicillin allergy

Why do so many Australians believe that they have a penicillin allergy? According to Dr Tong, it often begins in childhood.

“Many patients say their parents told them. For example, one person has a reaction and the parents are concerned others in the family could be allergic, even though penicillin allergy is not inherited,” Dr Tong says.

Some people have experienced a reaction to penicillin as children, been labelled as allergic, and then avoided it ever since.

However, if more than a decade has passed since that initial reaction, 80 per cent of people will no longer have the allergy over time.

There are several other reasons why someone could be incorrectly labelled as allergic to penicillin.

Some people experience drug side effects which are mistaken as an allergic reaction.

Removing the penicillin allergy ‘label’

“Medicine is a risk averse system. It’s very easy to label someone as allergic and tell them to avoid penicillins for the rest of their life. But it’s very difficult then to safely say to someone, you can take away that label, and you can have penicillins,” Dr Tong says.

Taking away the label (de-labeling) usually occurs in a hospital setting with a specialist immunologist, along with doctors and nurses to monitor the patient in case of a reaction. This means that the process is expensive and patient capacity is limited. For example, Dr Tong’s wait time is between six to twelve months depending on the patient’s condition.

Also, once a patient completes allergy testing and their penicillin allergy label is removed, patients can still be concerned about their penicillin allergy status.

“The problem is you do all this testing and the patient still won’t take penicillin. Maybe they didn’t understand the results, or their GP didn’t get the results letter,” Dr Tong says.

Improving patient communication

Dr Tong did some interesting research with seven hospitals across Sydney that were involved in allergy testing.

After undergoing testing and receiving results, more than half the patients did not understand whether they were allergic to penicillin or not. Because of this, many patients who turned out not to be allergic were still refusing penicillin antibiotics.

Obviously, the whole point of testing is to not only find patients who wrongly claimed to be penicillin allergic but also to convince those patients it was safe to take penicillin antibiotics.

This prompted researchers to develop standardised methods for communicating with patients. These include verbal discussion of results on the day of testing, results letters and updating of electronic medical records. This time, 92 per cent of patients understood their allergy status.

What you can do

 It is important to find out if you are allergic to penicillin because bacterial infections are all fought with antibiotics.

Apart from being effective, penicillin-based antibiotics are less likely to reduce your resistance to future infections.

If you think you are allergic to penicillin, it’s very well possible that you are not. Talk to your GP about getting tested.

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