Authors (including presenting author) :
Lo JCK (1), Li AWT (1), Chan TCC (1), Mak CCY (1), Mak RWM (1), Hooi JKY (2), Chu GKH (2), Wong JCY (2), Wong VKC (1), Wong HSY (1), Li PH (2)
Affiliation :
(1) Department of Pharmacy, Queen Mary Hospital, Hong Kong, (2) Division of Rheumatology and Clinical Immunology, Department of Medicine, Queen Mary Hospital, Hong Kong
Introduction :
Penicillin allergy mislabelling hampers effective antibiotic therapy and is associated with increasing multidrug resistance, prolonged hospital stays and elevated healthcare costs. Over 8,000 new beta-lactam allergy labels are generated annually but there are inadequate allergists to timely review the questionable labels. Non-allergists such as pharmacists have been trained to offload allergists’ burden worldwide. At Queen Mary Hospital (QMH), since January 2024, Penicillin Allergy Label Stewardship (PALS) has been implemented through a multi-disciplinary approach.
Objectives :
To prevent inaccurate penicillin allergy labelling for low-risk patients with no documented label or documented label but unconfirmed histories
Methodology :
Since 1 January 2024, patients with self-reported or documented but dubious penicillin allergy from different pilot departments of Hong Kong West Cluster (HKWC) were referred to and triaged by PALS Pharmacists. After case reviews with allergists, low-risk penicillin allergy patients would receive allergy tests such as skin tests and oral challenge performed by PALS Pharmacists. Immediate and delayed reactions were assessed to determine if the allergy labels were genuine and should be formally documented. Also, Drug Hypersensitivity Quality of Life Questionnaire (DrHy-Q) was used to measure changes in health-related quality of life. Phone follow-up was done to trace subsequent penicillin reuse.
Result & Outcome :
By 31 March 2025 , 88 patients were recruited under PALS pathway (75 patients with documented but dubious penicillin allergy labels and 13 patients were unlabeled). Among the 52 out of 88 referred patients who completed allergy tests, delayed allergic reactions accounted for 40.4% and immediate allergic reactions accounted for 21.2%. Inaccurate penicillin allergy labels were successfully prevented in 94.2% low-risk patients and no severe systemic reaction occurred. The successful label prevention rate was comparable to the previously published penicillin allergy delabelling rate of 93-94% by allergists and 90-93% by non-allergists in Hong Kong. The mean DrHy-Q scores changed from 35.7 points at pre-evaluation to 16.3 points at post-evaluation, showing a leap of betterment in health-related quality of life. At median 211 days after seen at post-evaluation clinic, 29.3% patients safely reused penicillin.
This pilot pharmacist-led, protocol-driven low-risk penicillin allergy evaluation in PALS was safe, effective and impactful in preventing self-claimed and doubtful penicillin allergy labelling.
