Background: Self-reported penicillin (PCN) allergy affects 7-10% of the community population and affects almost 20% of hospitalized patients nationally [1,2]. Mislabeling of side effects (gastrointestinal symptoms) or coincidental events (headache) as a true allergic reaction (IgE-mediated type I hypersensitivity) contributes largely to statistics. In recent studies, the rate of positive skin test results to PCN in self-reported PCN allergic patients is only 1% to 8%. Unverified PCN allergy in hospitalized patients is associated with longer hospital stays and increased rates of serious drug-resistant infections [3]. Patients with self-reported PCN allergy frequently receive suboptimal antibiotic therapy, which is associated with higher health care costs and increased morbidity. The Choosing Wisely campaign of the American Board of Internal Medicine Foundation recommended in 2014 that clinicians do not overuse non-beta lactam antibiotics in patients with a history of PCN allergy, without an appropriate evaluation [4]. The aim of study was to assess the prevalence and characteristics of self-reported PCN allergy among adult inpatients admitted to Lincoln Medical Center.
Methods: Retrospective analysis from January 2016 – June 2019 of all adult inpatients with self-reported PCN allergy was performed. Patient characteristics included clinical history consistent with a true PCN allergy, mislabeled side effects, coincidental effects, coexistent asthma and allergies, and admitting diagnosis. Use of alternate antibiotics among patients admitted with infections and prevalence of infections due to methicillin-resistant Staphylococcus aureus (MRSA) and/or vancomycin-resistant enterococcus (VRE) were also examined.
Results: The prevalence of self-reported PCN allergy among all admitted inpatients was 4.2%. Our cohort included 2,742 patients with selfreported PCN allergy, of which 995 (36%) were males and 1,747 (64%) were females. 376 (14%) patients had true PCN allergy, while 1,799 (65%) patients had other adverse symptoms not consistent with a true PCN allergy and 567 (21%) patients had no documented allergy symptoms. 31 patients had mislabeling of side effects (nausea/vomiting), while 16 had coincidental effects like dizziness and headache. 679 (25%) patients had a history of asthma, while 761 (28%) patients had other co-existent allergies. Of the 422 (1%) patients admitted for infection, 160 (38%) patients had respiratory tract infections, 119 (28%) patients had skin and soft tissue infections, and 69 (16%) patients had genitourinary infections. 344 (81%) patients required alternate classes of antibiotics – vancomycin (120 patients; 35%), carbapenem (42 patients; 0.2%) and quinolone (238 patients; 69%) – for management of infections during their hospital stay. Among these individuals, 117 (34%) patients received suboptimal therapy, and 32 (9%) patients in the cohort had MRSA infection while 12 (3%) patients had VRE infection.
Conclusions: Routine performance of PCN allergy testing for patients with self-reported PCN allergy will lead to a greater proportion of patients safely receiving penicillin [5]. This will decrease costs of care, enhance patient safety, improve outcomes of care, and reduce emergence of multidrug-resistant infections.