Background: Approximately 5-10% of the US population reports a Penicillin (PCN) allergy. Only 1 in 10 of these patients are found to have a positive reaction to PCN. This label comes at a grave cost, with higher incidences of multidrug-resistant nosocomial infections reported among these patients. With the lack of novel antibiotics and the alarming progression of resistant organisms, appropriate antibiotic therapy is now crucial. The most important and underappreciated benefit of PCN skin testing is the conversion to appropriate antibiotic therapy
Methods: A resident driven ”Procedure Team’’ trained and supervised by attending hospitalists, performed PCN skin testing from March to November 2017, on reported PCN allergic patients admitted to Lenox Hill Hospital. Those with a history of severe hypersensitivity reaction to PCN (e.g. Steven Johnson, Toxic Epidermal Necrolysis and recent anaphylaxis), who used antihistamines or steroids within 48 hours, were excluded. Testing was performed by means of standard methods using benzylpenicilloyl-polysine (Pre-PEN), penicillin G (PenG), histamine and saline controls. During the scratch test, a wheal >3 mm at the PenG or Pre-PEN site was considered positive. Patients with a negative scratch test received intradermal testing. An increase in size from the original wheal by 3 mm was read as positive. Negative tests were communicated with the primary team and the allergy was “re-labeled” as negative PCN skin-test in the chart. We then retroactively monitored for change of antibiotics after PCN testing and documented adverse reactions
Results: After exclusion criteria, 42 patients were included in this study. The majority reported rash/hives (59.5%) and remote anaphylaxis (19%) as their PCN allergy. Out of the 42 patients, 37 (88.1%) tested negative, with only 1 positive PCN reaction (2.4%). Of those with a negative test, antibiotics were changed over 80% of the time (30/37) to a PCN or Cephalosporin, with no subsequent adverse reaction. Notably, nearly all patients on Cefepime (4/4; 100%), Vancomycin (7/8: 87.5%), Carbapenem (3/4; 75%) and Aztreonam (8/11: 72.7%) were switched to a PCN or Cephalosporin. Conversion of antimicrobial therapy occurred the same day of PCN testing in all patients
Conclusions: Self-reported PCN allergy has grave clinical and economic implications. Our antibiotic stewardship initiative underscores how PCN skin testing can safely and rapidly alter the agent prescribed for skin-test negative patients. It is unfortunately underutilized despite its potential to improve care, antibiotic stewardship and overall healthcare costs. Given the opportunity for improved morbidity/mortality, it is worthwhile to investigate ways in which such initiative can become a universal practice across all hospitals.