The Incidence of Antimicrobial Allergies in Hospitalized Patients

Abstract

THE REPORTED incidence of allergic reactions to penicillin ranges from 1% to 10%^1,2; however, the true incidence of anaphylactic (life-threatening) reactions is in the range of 0.004% to 0.015%.² Often, patients are labeled as allergic to penicillin in their medical record without an in-depth investigation as to the nature of their reaction. When questioned about their reactions, many patients who report an allergy to penicillin do not meet the criteria for a true drug allergy^3-6 and have in fact received a cephalosporin or a penicillin in the past without adverse effects.⁵ Also, some patients reporting an allergic reaction to penicillins (β-lactams), especially those without anaphylaxis, can subsequently receive a related class of antimicrobials, the extended-spectrum cephalosporins.^7,8 Therefore, proper classification and documentation of the allergic reaction is essential before choosing empiric antimicrobial therapy in patients reporting an allergy to penicillin.