Improved Documentation May Help Distinguish Beta-Lactam Allergy vs Intolerance

SAN FRANCISCO— A documented beta-lactam allergy was found in more than one-third of patients receiving broad-spectrum antibiotics, according to a study presented at the annual IDWeek conference, held October 3-7, 2018, in San Francisco, California.

Beta-lactam antibiotics are often indicated as first-line therapy for a diverse range of infections, and alternative therapies carry toxicities and increased risk for antimicrobial resistance. However, in the United States, allergy to beta-lactam antibiotics, especially penicillins, is the most commonly reported drug allergy. When tested for this allergy, however, only 10% of patients have a beta-lactam allergy. Patients with a documented, but usually unverified, history of beta-lactam allergy are often given excessively broad-spectrum antibiotics as alternative treatment. Because these antibiotics have differing adverse effects and toxicities and may contribute to antimicrobial resistance rate, inaccurate documentation of beta-lactam allergy has been demonstrated to effect health outcomes adversely.

Over a 6-month period, a retrospective chart review of meropenem, aztreonam, and linezolid — commonly identified as alternative treatments for individuals with beta-lactam allergy — was conducted at a county medical center. Allergy documentation, therapeutic indication, and appropriateness of therapy were analyzed in this study. For the purpose of this review, beta-lactams were defined as penicillins, penicillin derivatives, or cephalosporins.

Of the 296 cases reviewed, 257 were unique patients, of whom 35% had a documented beta-lactam reaction, although most reactions were not described effectively. Rash was the most common reaction (47%), followed by type I hypersensitivity (28%), unknown (12%), and intolerance (9%). Lower respiratory infection was the most common indication for therapy (24%). Reviewer assessment stated that 83 of 296 patients received one of theaforementioned antibiotics because of a history of beta-lactam reaction.

In conclusion, beta-lactam allergy was documented in more than one-third of patients receiving broad-spectrum antibiotics. “Improved documentation may help distinguish true allergies from intolerances and reduce broad-spectrum antibiotic use,” the study authors stated.

LaNasa R, Narayan M, Ahiskali A, Zadroga R. Broad spectrum antibiotic use in relation to β-lactam allergies. Presented at: ID Week 2018; October 3-7, 2018; San Francisco, CA. Poster 35.