Many Americans think they have this allergy — but only 1% do

You’ve been itching to avoid this antibiotic — maybe for no reason.

Penicillin was discovered in 1928 by a Scottish bacteriologist. The medication has since become a common treatment for a range of bacterial infections, including strep throat, pneumonia, skin infections and certain urinary tract infections.

But not everyone can tolerate penicillin. People allergic to the drug may suffer hives, itchy skin, a rash or, in severe cases, a potentially life-threatening reaction known as anaphylaxis upon exposure.

These patients may struggle to breathe, feel dizzy or experience facial swelling.

The good news is that penicillin allergies are far less common than once believed.

Studies have shown that over 90% of people who report a penicillin allergy aren’t actually allergic when tested. Less than 1% of Americans are truly allergic.

“Incorrectly being labeled as allergic to penicillin can prevent you from getting the most appropriate, safest treatment for an infection,” Dr. Elizabeth W. Covington, an associate clinical professor of pharmacy at Auburn University, recently wrote in The Conversation.

“It can also put you at an increased risk of antimicrobial resistance, which is when an antibiotic no longer works against bacteria,” she added.

Those reporting penicillin allergies are often treated with broad-spectrum antibiotics, which target lots of different types of bacteria.

Covington noted that this puts helpful bacteria in the cross-hairs, potentially paving the way for the survival and spread of antibiotic-resistant bacteria.

“Broad-spectrum antibiotics … aren’t always the best fit and can have more side effects” than penicillin, she said. “What’s more, your medical bills could end up higher due to using more expensive drugs.”

People tend to get mislabeled as allergic to penicillin if they have a rash, nausea, diarrhea or headaches after taking an antibiotic as a child, Covington reported.

But those reactions can be common side effects of antibiotics or triggered by the illness itself.

“People also often assume penicillin allergies run in families, but having a relative with an allergy doesn’t mean you’re allergic — it’s not hereditary,” Covington said in The Conversation.

“Finally, about 80% of patients with a true penicillin allergy will lose the allergy after about 10 years,” she continued. “That means even if you used to be allergic to this antibiotic, you might not be anymore, depending on the timing of your reaction.”

How to tell if you’re allergic to penicillin

Talk with a doctor or pharmacist about any symptoms you have after taking antibiotics.

Be sure to note when the reaction began, whether treatment was needed and what happened with subsequent attempts at taking similar drugs.

“In many cases, this interview is enough to determine you aren’t allergic,” Covington said. “But sometimes, further testing may be recommended.”

Penicillin skin testing typically involves putting a small amount of penicillin solution on the forearm and pricking or scratching the skin to let the solution enter.

Then you’re observed to see if you develop redness or raised bumps.

If the skin test is negative, an immunologist may administer a small oral dose of the drug and monitor you for signs of a reaction.

Memorial Sloan Kettering Cancer Center said the skin and oral testing typically takes 90 minutes to two hours.

The NYC-based cancer hospital suggests wearing a short-sleeved shirt for the test, which allows for easy access to your arm, and eating a meal or snack beforehand to prevent cramping, gas and bloating.