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Think You Have a Penicillin Allergy? Chances Are, You Don’t. Why This Matters.

By Dr. Katherine McCormack, MD
Allergy, Asthma & Immunology at Boulder Medical Center

Did you know that the vast majority of individuals who think they have a penicillin allergy actually don’t? It’s true! Penicillin is the most commonly reported drug allergy in the United States, but 9 out of 10 patients who report a penicillin allergy aren’t truly allergic.

When a patient carries a penicillin allergy label, their healthcare can be impacted in a number of ways. In a hospital setting, a penicillin allergy may translate to a 10 percent increase in number of days admitted to the hospital and a 14 to 30 percent increase in serious, resistant infections. You may also feel the effect of penicillin allergy on your wallet. It has been estimated that patients who report this allergy spend 63 percent more on antibiotics.

On a wider scale, antibiotic resistant bacteria are on the rise and continue to increase every year. The Centers for Disease Control (CDC) notes that properly identifying patients who are penicillin-allergic can decrease the unnecessary use of broad-spectrum antibiotics and help combat the development of superbugs. Identifying patients who can safely take penicillin, can enable doctors to prescribe more appropriate and safer antibiotics.

How are penicillin allergies misdiagnosed?

A number of factors can lead to a misdiagnosis. For instance, some side effects of penicillin and symptoms of illnesses can be similar. Perhaps you were sick in the past, received penicillin, and experienced a skin rash. These symptoms could have been related to a viral or bacterial infection on it’s own or may have resulted from a true penicillin allergy. If you were not specifically tested, you may have been misdiagnosed as allergic.

Also, even if you were allergic to penicillin at one time in your life, it’s possible that you may no longer be. According to the CDC, approximately 80 percent of patients with a penicillin allergy lose their sensitivity after 10 years.

How can I find out if I’m allergic to penicillin?

Today, we have skin test methods to help identify patients who may be truly penicillin allergic and those who are not. Pending your clinical history, testing for a penicillin allergy with skin scratch tests followed by a test placed just under the skin may be recommended. If you test negative, an observed oral ingestion of the medication is performed to ensure that you will not have an immediate reaction the next time you require the medication. The first ingestion is performed under supervision with a team experienced in treating allergic reactions in the unlikely event there would be a severe reaction to the medication.

About Dr. Katherine McCormack, MD

Allergy, Asthma and Immunology Specialist at Boulder Medical Center

As part of the Allergy Department at Boulder Medical Center, Dr. Katie McCormack treats infant, youth and adult patients for everything from seasonal and food allergies to asthma and eczema. She strives to educate, inform, and empower her patients to become participants in their own wellness and care.

Dr. McCormack welcomes new patients in her Louisville, Colo. clinic. She regularly sees patients from throughout Boulder County along with those from nearby communities, including Broomfield, Westminster, Arvada, Golden.

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