LAUSR

Narayanan and Jeffres recently reviewed the feasibility, benefits, and limitations of an inpatient penicillin allergy skin testing service. As the authors commented, penicillin skin testing is the most reliable method to evaluate immunoglobulin E (IgE)-mediated penicillin allergy and can serve as a useful antibiotic stewardship tool. However, it is not feasible in multiple settings and may not be an efficient or practical tool to manage patients with reported penicillin allergy. Penicillin allergy is the most common drug allergy reported on hospital admission. However, only 10% of the patients labeled as penicillin allergic have IgE-mediated reactions on penicillin skin test. More than 98% of those with the positive skin test can tolerate other β-lactams, cephalosporins, and carbapenems. Despite these facts, reported penicillin allergies often lead to unnecessary avoidance of preferred β-lactams, causing clinicians to bypass first-line antibiotics and prescribe alternative or broad-spectrum antibiotics, which are associated with poor clinical outcomes and higher health care costs. Aztreonam is one of the widely used alternatives to treat Gram-negative organisms in patients with reported penicillin allergy because of its negligible cross-reactivity with penicillins. However, aztreonam may not be an optimal antibiotic because it is 10 to 50 times more expensive and has limited or reduced susceptibilities to common nosocomial pathogens, extended-spectrum β-lactamase–producing organisms and Pseudomonas aeruginosa when compared with other β-lactams. Our antibiotic stewardship committee developed a simple penicillin allergy algorithm for the primary team to use and make decisions regarding the most appropriate empirical or definitive antibiotic in patients with reported penicillin allergy. The algorithm (Figure 1), adapted from the drug allergy practice parameters, consists of 2 essential parts: review of the 758320 AOPXXX10.1177/1060028018758320Annals of PharmacotherapyLetter to the Editor letter2018