Removal of incorrect penicillin allergy labels in a UK hospital

Objectives: Penicillin allergy records are common, often incorrect and are associated with broad spectrum antibiotic use. We piloted a pharmacist-led multidisciplinary penicillin allergy de-labelling daily ward round to determine the opportunity for penicillin allergy de-labelling in a UK hospital. Methods: A daily ward round, delivered by antibiotic pharmacists or junior doctors, identified adult medical and surgical patients between 7 November 2022 and 31 January 2023 with a penicillin allergy record that was preventing first-line penicillin use. An allergy history was taken before risk stratifying likelihood of future harm from penicillin re-exposure and an allergy testing method was determined (direct de-label on history alone or after direct drug provocation testing). After successful allergy de-label, the antibiotic was switched to a penicillin antibiotic. Results: Of 7214 inpatients during the study period, 1133 (15.7%) had a penicillin allergy record. Of 285 allergy histories taken, 105 (36.8%) met high-risk criteria, 45 (15.8%) met low-risk criteria eligible for direct de-label and 73 (25.6%) met criteria eligible for direct drug provocation testing. We were unable to obtain a history for 61 (21.4%) patients. Of 45 low-risk patients eligible for direct de-label, 40 (88.9%) were de-labelled of whom 24 (53.3%) were switched to a penicillin antibiotic. Of 73 patients with a low-risk allergy history eligible for direct drug provocation testing, 16 (21.9%) received direct drug provocation testing, of whom 9 were switched to a penicillin antibiotic. Two direct de-label patients experienced harm (thrush within 5 days and delayed skin reaction after day 5); none of the direct drug provocation testing patients had a reaction by day 5. The switches resulted in reduced alternative antibiotic use by 173 Daily Defined Doses (DDDs). Discussion: Penicillin allergy de-labelling patient pathway delivered by pharmacists and junior doctors was safe and effective and well accepted by patients and the wider clinical teams.