Authors: Rob Hirst, Liz Farah, Andy Neill, Dave McCreary, Becky Maxwell, Chris Connolly/ Codes: CP4, SLO1, SLO5, SLO9, TP7 / Published: 05/02/2024

  • Andy Neill
  • Dave McCreary
Clinical question
  • Is it easy to de label penicillin allergy Authors - Copaescu et al JAMA Internal Medicine 2023
  • Efficacy of a Clinical Decision Rule to Enable Direct Oral Challenge in Patients With Low-Risk Penicillin Allergy The PALACE Randomized Clinical Trial
  • We see lots of people with a label of penicillin allergy. The history is usually remote and vague and is almost always erroneous (>95% in fact). Yet, understandably we are reluctant to give anything that might hurt the patient. However limiting ourselves to non penicillin antibiotics really limits our choices and may well expose them to potentially more toxic choices (cipro anyone?!?) - if we can safely question and challenge and de label then we've done the patient a great good. - typically delabelling involves some questions, then some skin prick testing then eventually an oral challenge of penicillin. All a bit cumbersome. There does exist a clinical decision rule called PEN-FAST that allows risk assessment and this study assessed whether a low risk score followed by oral challenge is safe
  • Multi centre non inferiority randomised trial - 6 outpatient clinics in North America and Australia. and yes I know, there is not an ED in sight here, we'll come back to that... - included if they were referred with a penicillin allergy and a low PEN-FAST score. Exlcuded those with a history of anaphylaxis and importantly excluded those with symptoms that were suggestive of a simple antibiotic side effect (eg nausea or headache) - randomised to either direct oral challenge or the more traditional approach of pin prick followed by oral challenge. - primary outcome was a definied bad reaction within 60 mins of penicillin. - non inferiority margin of 5% assuming control group rate of reaction of 2%. they acknowledge this is quite big but given how rarely it happens they were still comfortable with it Results - 380 patients - 1 patient in each group had a reaction. Both of which were quite minor needing an antihistamine
  • I acknowledge this is not at all ED based but we must admit it has relevance. How many times are you reaching for antibiotics you don't really want to use because there is some history of penicillin allergy somewhere. Of course we should study this in the ED before we implement it but it does seem very good - I do know someone locally who is doing this all the time in the ICU population. And if you can do it in that cohort then no doubt it is feasible in the ED. - the PEN-FAST score is easy to do. Uses FAST as an acronym with F - five years or less since reaction A - anyphaxis, angioedema S - severe cutaneous reaction T - treatment required for reaction.