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Bacterial Pneumonia Patients With a Penicillin Allergy Label Face Worse Clinical Outcomes

AAAAI News Release

September 28, 2022

April Presnell, Media & Member Communications Manager
(414) 272-6071

Penicillin allergy labels have negative consequences in bacterial pneumonia patients, when many with these labels can safely receive penicillin, according to new research published in an official AAAAI journal on National Penicillin Allergy Day.

Bacterial pneumonia patients who have a penicillin allergy label have a higher risk of hospitalization, acute respiratory failure, intubation, intensive care admission and mortality rates compared to patients who do not have a penicillin allergy label, according to research published on National Penicillin Allergy Day in The Journal of Allergy and Clinical Immunology: In Practice (JACI: In Practice), a journal of the American Academy of Allergy, Asthma & Immunology (AAAAI). National Penicillin Allergy Day is celebrated each year on September 28, the anniversary of Alexander Fleming’s discovery of penicillin. The day is designed to raise awareness of the adverse impact of carrying a penicillin allergy label and how it affects a patient’s healthcare treatment.

“Penicillin antibiotics are among the first-line treatment options pursued for bacterial pneumonia,” said Lauren W. Kaminsky, MD, PhD, first author of the study. “By having a penicillin allergy label, antimicrobial treatments may be delayed and alternative antibiotics may be used, putting patients at risk of suboptimal treatment of bacterial infections.”

Researchers identified adult patients with and without a penicillin allergy label who were diagnosed with bacterial pneumonia using TriNetX, a web-based tool for population cohort research. They then examined the 30-day risk of hospitalization, acute respiratory failure, intubation, need for intensive level of care and mortality. They also tracked antibiotics that were used within 30 days after a pneumonia diagnosis and possible adverse reactions to those antibiotics.

A total of 68,748 patients diagnosed with bacterial pneumonia who had a penicillin allergy label were included in the first cohort, with another 68,748 without the label included in the second cohort. These cohorts were matched on baseline characteristics and comorbid conditions. Researchers found that 69.2% of patients with a penicillin allergy label were hospitalized within 30 days of a bacterial pneumonia diagnosis compared to 56.2% of patients without the label.

Additional results showed that acute respiratory failure was diagnosed in 40.1% of patients with a penicillin allergy label compared to 35.3% of patients without, 8.6% were intubated (compared to 7.3% of patients without), and 14% required intensive care (compared to 12.6% of patients without). The 30-day mortality rate was also higher for patients with a penicillin allergy label at 6.2% compared to 5.7% for patients without the label.

When looking at potential adverse outcomes of antimicrobial use, researchers found C. difficile infection was more likely to occur in patients with a penicillin allergy label (5.75% compared to 5.12%), as well as drug-induced rash (0.83% compared to 0.39%). Researchers also observed a higher rate of acute kidney injury in patients with a penicillin allergy label (23.6% compared to 20.4%) and toxic liver disease (0.32% compared to 0.22%).

Less than 10% of patients with a penicillin allergy label are truly allergic, and testing from a qualified allergist can clarify a penicillin allergy diagnosis. “Our study supports that penicillin allergy labels have negative consequences in patients with bacterial pneumonia, and many of those patients with those labels can safely take penicillin,” said Dr. Kaminsky. “It’s important to prioritize penicillin allergy delabeling efforts by taking detailed histories and performing skin testing or drug challenges so that patients with these penicillin allergy labels who aren’t truly allergic can have them removed and receive optimal care.”

You can learn more about penicillin allergy on the American Academy of Allergy, Asthma & Immunology website, The AAAAI also has a Penicillin Allergy Center with free resources to help promote National Penicillin Allergy Day and the benefits of penicillin allergy testing and delabeling.

The American Academy of Allergy, Asthma & Immunology (AAAAI) is the leading membership organization of more than 7,100 allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic and immunologic diseases. The AAAAI is the go-to resource for patients living with allergies, asthma and immune deficiency disorders. Established in 1943, the AAAAI has more than 7,100 members in the United States, Canada and 72 other countries. The AAAAI’s Find an Allergist/Immunologist service is a trusted resource to help you find a specialist close to home.