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It’s time to go to urgent care or your primary care doctor for a minor infection, or maybe you’re in the hospital for surgery or a procedure. Without fail, you always remember to remind your doctors about your penicillin allergy.
It’s important to stay on top of your medication allergies, because it really could be life or death. However, it turns out a lot of people who think they have a penicillin allergy might not actually be allergic. Here’s what to know.
What is an antibiotic allergy?
Your body works hard to keep you safe and healthy. But sometimes, the body mistakenly identifies a medication as a harmful substance and sends an immune response to attack it.
“This response can occur at any point in time, even to medications you’ve tolerated in the past,” says Kelly Colas, DO, PhD, an allergy and immunology doctor at the Allergy, Asthma and Immunology Clinic at Northwest Outpatient Medical Center.
That includes penicillin and related antibiotics like amoxicillin, Augmentin, ampicillin and others. Your immune system thinks the antibiotic is a threat and launches a response against it.
All medications, including these antibiotics, can have side effects, like nausea, diarrhea or abdominal pain. While annoying, these symptoms are not necessarily signs of an allergy.
But if you take an antibiotic and develop symptoms such as itching, hives, wheezing or shortness of breath within an hour or two, it’s time to seek medical care. Some allergic drug reactions can trigger anaphylaxis, a severe allergic response including dangerously low blood pressure, loss of consciousness and death.
Some people can also experience a delayed allergic reaction, which typically occurs days to weeks after taking the medication. It most often causes an itchy rash, but can sometimes cause a severe rash, mouth ulcers, swollen lymph nodes, high fevers or liver and kidney problems.
Why you might not actually have an antibiotic allergy
Colas says most people who think they have an antibiotic allergy … actually don’t. About 10% of people report having a penicillin allergy, but when tested, over 90% don’t have a true allergy.
“For example, rashes are a very common symptom of many childhood illnesses, and penicillin antibiotics are often prescribed when children are sick,” says Colas. “In these situations, it can be confusing to know if it was the antibiotic that was prescribed or the illness itself that caused the rash, which can lead to being mistakenly labeled with a penicillin allergy.”
It’s also possible to outgrow your antibiotic allergy over time. Your immune system develops a tolerance to the medication and no longer sees it as a threat.
“After 10 years, over 80% of people no longer have a penicillin allergy,” says Colas. “That’s why it’s important to consider getting additional testing to know if you’re still allergic to a penicillin antibiotic.”
What to do if you think you’re allergic
If you think you have a reaction to penicillin, try to remember your symptoms and bring this info to your medical appointments so they can update your records. That info might be in your medical records. You might be asked questions like:
- How long ago did the reaction occur?
- What happened when you took the antibiotic?
- Did you have to seek treatment for the antibiotic reaction?
- Have you tolerated other antibiotics since?
Your healthcare team may recommend testing to confirm whether you’re truly allergic.
“For some types of antibiotics, like penicillin, your healthcare providers can perform additional testing to confirm whether or not you have an antibiotic allergy,” says Colas.
And in some situations, when it’s unlikely that your symptoms are caused by an allergy, your healthcare team might feel comfortable giving you a similar antibiotic without having specific testing first.
Even if you have had the “penicillin allergy” label on your medical chart since elementary school, it is still worth getting tested, since you might have been misdiagnosed or grown out of it. And not knowing whether you’re allergic can put your health at risk.
“If you’re not allergic to penicillin, sometimes alternative antibiotics that are used to treat or prevent infections can have more side effects, can be more expensive, can lead to longer hospital stays, and even increased risk of death,” says Colas.
Penicillin antibiotics are less likely to lead to complications like a Clostridioides difficile infection or antibiotic resistance, adds Ralph Tayyar MD, an infectious disease doctor at the University of Washington.
What to do after your allergy test
If it turns out you no longer have a penicillin allergy, make sure all your healthcare providers know the results — not just the person who did the test.
“If you’ve safely taken a penicillin antibiotic since your initial reaction or passed a penicillin allergy test, a penicillin allergy can be removed from your allergy list,” says Colas. “Remember to notify all your providers, including your dentists, pharmacists and your primary care doctor and anywhere else that you seek care, that you don’t have a penicillin allergy.”
Let’s say the tests come back and you, in fact, are allergic to penicillin. Don’t panic — depending on the infection being treated, other treatments or antibiotics can be used. If you’ve been diagnosed with an antibiotic allergy already, you know the drill.
Ultimately, the most important thing is to stay informed and have up-to-date, accurate information about your health so you can get the best possible care.
“Antibiotics are powerful tools to prevent infections after surgeries, and studies have shown that patients with penicillin allergies are at higher risk for infections,” says Rupali Jain, PharmD, infectious disease doctor at the University of Washington. “This can be due to less effective alternative antibiotics. So, it is important to talk to your provider about your penicillin allergy.”
