Could allergy testing improve antibiotic use?


new antibiotics: gloved hands holding two antibiotic capsules

Incorrect antibiotic allergy labels pose a significant public health issue, says an antimicrobial stewardship expert

More needs to be done to ensure Australia’s most vulnerable patients are not incorrectly diverted to second-line drugs, says Dr Jason Trubiano, Austin Health’s Director of Antimicrobial Stewardship and Drug and Antibiotic Allergy Services, and an Infectious Diseases Specialist at Peter MacCallum Cancer Centre.

Dr Trubiano also established Victoria’s first dedicated antibiotic allergy clinic, which is now operating at both sites.

In a perspective article published in the Medical Journal of Australia, Dr Trubiano says incorrect antibiotic allergy labels frequently prevent the use of appropriate narrow spectrum penicillin and targeted antibiotic therapies.

It’s often the sickest patients who suffer, he says.

“This clinic is now routinely testing patients to find those with antibiotic allergies wrongly listed on their record, so this does not unnecessarily limit the treatments they can receive,” says Dr Trubiano.

“By removing these incorrect antibiotic allergy labels we can restore patients’ access to first-line and preferred antibiotics – and this reduces the risk of treatment failure, post-surgical infection and an extended hospital stay.”

The over-application of antibiotic allergy labels also increases reliance on other widely-acting antibiotics which can promote the rise of antimicrobial resistance and superbugs, he says.

Dr Trubiano recently published a study of Austin Health and Peter Mac patients which showed most (83%) had an antibiotic allergy label that was incorrect and should be erased from their medical record.

Almost half (48%) of these patients were immunocompromised, with many receiving treatment for cancer or post organ or stem cell transplant.

Antibiotic allergy labels may not be confirmed at the time they are listed on a patient’s medical record. They can carry over from a childhood rash where a viral cause was possible, or patients may lose sensitivity over the years, effectively growing out of their antibiotic allergy.

Another recent study, also cited in the MJA article, found 81% of Australians who were listed as allergic to penicillin could have this label removed after testing.

 “We are calling for more awareness – patients with lowered immune systems need to be aware that many antibiotic allergy labels can be removed and thus open up their window of antibiotic choices,” Dr Trubiano says.

“We also need multidisciplinary centralised testing services like those on offer at Austin Health and the Peter Mac that focus on our vulnerable patients, as well as simple point-of-care allergy testing programs in each hospital to remove low risk and unlikely allergies.”

The antibiotic allergy testing at Peter Mac and Austin Health involves a skin-prick challenge under supervision.

Dr Trubiano and the team from the National Centre for Infections in Cancer (NCIC), based at Peter Mac, are also collaborating to develop novel blood tests and testing programs so that vulnerable patients suspected of having severe allergies can also be safely tested.

“In Australia, as many as one in four in-patients with cancer have an antibiotic allergy label, and their risk of being prescribed an inappropriate antibiotic is almost 50% higher than for patients without an antibiotic allergy label,” the MJA article states.

“It is reasonable to suggest that antibiotic prescribing in patients with reported antibiotic allergies would be improved through the incorporation of antibiotic allergy programs in antimicrobial stewardship (AMS) services.

“Comprehensive AMS programs which aim to guide appropriate selection, dosing, route and duration of antimicrobial therapy have been shown to decrease antimicrobial use by 22–36%, with annual savings of US$200 000–$900 000 in larger US academic hospitals.

“While the cost-effectiveness of an antibiotic allergy testing program needs to be examined in an Australian context, international assessments have shown that such a program can reduce antibiotic costs per patient.”

Simple measures such as “educating clinicians about antibiotic cross-reactivity, pursuing a viral aetiology instead of antibiotic prescription for childhood exanthems, forensically evaluating purported allergy in the electronic medical record, and deleting labels that are drug side effects (eg, gastrointestinal intolerance) are likely to significantly aid de-labelling efforts,” the article says.

“Raising the profile of antibiotic allergy in Australian health care and identifying vulnerable patients who would benefit from targeted antibiotic allergy testing are also likely to have a significant impact on antibiotic prescribing practices.”

Patients who often take antimicrobials, especially those with an immune-mediated antibiotic allergy, are key targets for testing services.

“The establishment of multidisciplinary specialised antibiotic allergy testing referral centres involving allergists, infectious diseases physicians, AMS programs and pharmacists enables centralised testing with minimisation of program costs and provision of specialised interpretation.”

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