Issue 13 / 11 April 2016

EXPERTS are calling for the reassessment of antibiotic allergy labels (AAL) to help reduce the widespread use of broad spectrum antibiotics.

Associate professor of medicine at the Australian National University and infectious diseases physician, Sanjaya Senanayake, told MJA InSight that “as doctors, whenever we see ‘allergy hyphen penicillin’ written on a patient’s notes, this needs to be investigated further”.

He said that making the distinction between a true allergy and an adverse drug side effect, like nausea or a rash, was essential in addressing the growing problem of antibiotic resistance.

“If we find it was a symptom of benign origin, we have the opportunity to give plain old penicillin as opposed to broad-based antibiotics, and we should take it.”

Professor Senanayake was commenting on research published today in the MJA which found the prevalence of antibiotic allergy labels was 24% among general medicine inpatients.

The study included 453 people with a median age of 82 years who were admitted to the general medicine units of Austin Health and Alfred Health over a 3-week period in 2015.

A questionnaire was administered to clarify any AAL history, which was followed by a correlation of responses with electronic and admissions record descriptions. A hypothetical oral-rechallenge in a supervised setting was offered to patients with low-risk allergy phenotypes.

The authors found that 107 patients had an AAL. Most of these patients were women, and more presented with concurrent immunosuppression than those without AAL.

A total of 54% of patients with AALs were willing to undergo an oral rechallenge, of whom 48% had a low-risk allergy phenotype.

The authors wrote that AALs were associated with increased prescribing of ceftriaxone and fluoroquinolone, antibiotics commonly restricted by antimicrobial stewardship programs.

“These findings inform a mandate to assess AALs in the interests of appropriate antibiotic use and drug safety.”

Lead author of the study and infectious diseases registrar at Austin Health, Dr Jason Trubiano, said in an MJA podcast  that it was frustrating “when our well-laid antibiotic plans are undone by an allergy label”.

However, these allergy labels were also of detriment to the patient, as an antibiotic like penicillin was far superior in treating community-acquired pneumonia, blood infections, and urinary tract infections compared to the broad spectrum alternatives.

“We have to try and find out how big the burden is, and what we can do to correct that in the future through dedicated antibiotic allergy services, oral challenges, or just rubbing them off the drug chart,” Dr Trubiano said.

Peter Collignon, professor of microbiology at the Australian National University, told MJA InSight that the high rate of AAL prevalence revealed by the research was significant, particularly among an elderly group of patients.

“It is likely that a lot of these allergies categorised as low risk were not in fact allergies, but adverse reactions.”

Professor Collignon said it was essential for GPs to determine how long ago the patient had their reported antibiotic reaction.

“Many years ago, antibiotics like penicillin could end up with impurities in them, so it could have been the impurities that the patient was reacting to and not the antibiotic itself.”

He said that if a patient reported symptoms that were indicative of an adverse drug side effect, like a rash or nausea, it was feasible for the GP to perform an oral challenge in a safe environment.

Professor Senanayake agreed, adding that “some GPs might feel more confident if this was done in a hospital where there is 24-hour care, but they should remember that they can always call for advice from a specialist, or a hospital, whenever they need it”.

Dr Trubiano said the next step now was to determine what existing services were available for GPs to manage the documentation of these allergies, and how new services could be implemented.

“We’ve created two dedicated antibiotic allergy clinics here at Austin Health and the Peter MacCallum Centre,” he said.

“Effectively, they’re de-labelling clinics where they want to get people in, test them, and remove the allergy label.”

He said the work these clinics were doing was highly effective, with previous research suggesting that it is possible to remove around 90% of people’s allergy labels.

However, it is essential to also develop simpler and cost-effective measures that GPs could roll out themselves.

“GPs are at the forefront and hopefully [this AAL burden] could be stopped in the GP clinic,” Dr Trubiano said.


Poll

Are antibiotic allergies worth rechallenging?
  • Yes, it would widen prescribing choice (75%, 81 Votes)
  • Maybe, under the right supervision (24%, 26 Votes)
  • No, it's quicker to prescribe something else (1%, 1 Votes)

Total Voters: 108

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