Three-Year Effectiveness of a Multidisciplinary Approach to Penicillin Allergy De-labelling in Pregnant Patients

Allergy testing and de-labelling for pregnant patients reporting penicillin allergies is standard care to promote first-line antimicrobial use in the peripartum period. We aimed to evaluate the rate of penicillin allergy label reappearance ("sticky label phenomenon") in pregnant patients who underwent multidisciplinary allergy de-labelling during the antenatal period.

We completed a prospective cohort study of pregnant patients who successfully completed an antenatal oral amoxicillin challenge from July 2019 to December 2020. We conducted a chart review after 3 years to identify whether allergy documentation had returned to their electronic medical record and the provincial pharmacy database. Pregnant patients referred to the clinic for allergy testing but not assessed were used as the control group. Statistical analyses were completed using chi-square, Fisher exact, and Wilcoxon rank tests.

Our cohort included 246 persons with 110 de-labelled clinic patients in the intervention group and 136 controls. After 3 years, 2.7% (3 of 110) of clinic patients had persistent allergy documentation on their electronic medical record, compared with 22.8% (31 of 136) of control patients (OR 0.094; 95% CI 0.028-0.317; P < 0.001). A total of 1.8% (2 of 110) of clinic patients had persistent documentation on the provincial pharmacy database, compared with 28.7% (39 of 136) of control patients (OR 0.046; 95% CI 0.011-0.196; P < 0.001). A total of 4.5% (5 of 110) of clinic patients had the allergy listed on either database, compared with 44.9% (61 of 136) of control patients (OR 0.059; 95% CI 0.022-0.153; P < 0.001).

After antepartum multidisciplinary allergy de-labelling and patient education, the rate of reappearing penicillin allergy labels after 3 years is low.