Nov. 19, 2019&mdash;Think you're allergic to penicillin? You may be mistaken&mdash;like millions of other Americans. More than 30 million of us, in fact, may wrongly think we're allergic to this common antibiotic. 

How can so many people be so wrong? Many folks are diagnosed with a penicillin allergy in childhood, often because of a rash. But in many cases, that rash may have been caused by a virus, not an allergy. Others may have simply assumed they're allergic because a parent was. And even among people with a true penicillin allergy, 8 in 10 are no longer allergic 10 years later. 

Why does it matter? 

There's a huge cost to avoiding penicillin. It's one of the cheapest, safest, most effective antibiotics for many infections. People who avoid it may have to be treated with pricier, more powerful antibiotics with more side effects. 

Using these more powerful antibiotics may also fuel antibiotic resistance. That's what happens when bacteria evolve into "superbugs" that become harder and harder to kill. 

Clearing up the confusion 

Recent studies published in <a target="_blank" href="https://academic.oup.com/ofid">Open Forum Infectious Diseases</a> suggest two fairly easy ways to help identify people who wrongly believe they're allergic to penicillin. 

The first is a short survey that healthcare providers can give to patients. In one study, the questions alone were able to rule out an allergy in 20% of people who thought they were allergic to penicillin. 

The next step, if needed, is a penicillin allergy skin test (PAST). The skin is pricked with a small amount of penicillin to see if any skin irritation develops. If not, the person can be given penicillin drugs in a doctor's office and watched for a reaction. This kind of testing can rule out an allergy in many people. In fact, in one small study, researchers found that 98 out of 100 people with a penicillin allergy on their medical record were not really allergic, according to their PAST results. 

There's a clear takeaway here. If you think you're allergic to penicillin, talk to your doctor. Your medical history or a PAST may reveal otherwise. 

How much do you know about antibiotics? 

Used the right way, antibiotics can help you bounce back from an infection. But used the wrong way, they can be harmful. <a href="[BASEDOMAIN]/healthinfo/Story.aspx?StoryId=5E040FB5-88D1-44A2-8DD7-0BD79C10AA65">Test your know-how with this quiz.</a>

Are you really allergic to penicillin?

Millions of Americans may be avoiding this common antibiotic unnecessarily.