Most Penicillin Allergies Are Misdiagnosed — Here’s Why That Matters

With First Physicians Group Allergist John S. Trickett, MD

When penicillin was first mass-produced in World War II, it was hailed as a miracle drug saving countless lives, both on and off the battlefield. But as time went on, things started seeming a bit less miraculous, as more and more patients reported some sort of adverse reaction to the antibiotic.

Today, as many as 10% of patients are classified as allergic to penicillin. But according to First Physicians Group Allergist John S. Trickett, MD, studies have shown that the real number is probably closer to 1%—and this massive overdiagnosis is a real problem.

“The most common source of a suspected penicillin allergy is the appearance a benign rash during childhood,” Dr. Trickett says. “But that could actually have been caused by the infection the antibiotic was supposed to be treating.” Similarly, antibiotics like penicillin can sometimes cause headaches and gastrointestinal discomfort, which are side effects but don’t necessarily indicate a true allergy. “And even if it was an allergic reaction,” Dr. Trickett continues, “many patients outgrow that allergy within just a few years.”

Which is why he’s calling for more patients and physicians to get proactive about testing and confirming penicillin allergies.

“This affects a lot of people,” he says. “And it’s more important than they realize.”

How to Confirm a Penicillin Allergy

Confirming (or disproving) a penicillin allergy is simple and easy.

Schedule an appointment with an allergist in your area. At this appointment, you and the physician will review your medical history—particularly the type and severity of suspected symptoms. These can range from mild and non-concerning, such as headaches or gas, to something more troubling, such as hives, swelling, or even anaphylaxis.

The next step is testing. This is most often done with what allergists call “graded challenge,” which is about as direct as an allergy test gets. The process is simple, and the results are definitive. To start, the allergist gives the patient a small amount of a penicillin medication, then closely monitors for an allergic reaction. If there is no reaction, which is typically the case, the patient is given the rest of the dose and again monitored for any reaction. Rarely allergic reactions can happen, which is why this testing is completed in the office under the supervision of a physician. While severe reactions are possible, most are mild and easily treated. ;

Some patients with more severe reactions to penicillin benefit from skin testing prior to a graded challenge. The allergist uses a slight prick or scratch to expose the patient’s skin to a very small amount of penicillin, then waits 15 minutes to see the extent of the reaction, if any. Sometimes this is followed a small amount of penicillin placed under the skin. This can help the allergist better understand the risk of a severe reaction to penicillin. If skin testing is negative, the next step is the graded challenge described above. Once a patient has tolerated a full dose of amoxicillin, they are deemed no longer allergic to penicillin, and their allergy label is removed from their chart.

Penicillin allergy testing is safe enough that even pregnant women can be tested..

In fact, Dr. Trickett says, it’s important that they do. Verifying a recorded penicillin allergy is particularly important for pregnant women or women planning on having children, says Dr. Trickett, as it can be crucial in treating potentially serious infections, such as Group B Strep, or GBS.

“In pregnancy, it’s clear that penicillin is the best treatment,” he says.

Why It’s Important to Verify Penicillin Allergies

If someone is allergic to penicillin, verification ensures future healthcare providers do not prescribe it and are careful about antibiotics in the same family, such as amoxicillin. Dr. Trickett also adds: “Even if a patient is deemed to be truly allergic to a certain penicillin antibiotic by their allergist, their allergist can consider additional testing and provide recommendations on potential alternatives within the penicillin family that may be safe to take.”

The benefit is clear. Even if you’ve been told to avoid all penicillin-family antibiotics, that may no longer be necessary given new data that has come to light over the last few years.

For those wrongly diagnosed as allergic to penicillin, correcting that mistake can have many benefits.

1. Shorter hospital stays: Penicillin is one of the most effective antibiotics available, and an allergy will require using a less effective antibiotic.
2. Lower healthcare costs: Not only is a shorter hospital stay less expensive, but penicillin itself is also one of the least expensive antibiotics.
3. Less risk of complications: Being able to use penicillin and other antibiotics from that family lowers risk of developing serious antibiotic-resistant infections and side effects, when compared to the broad-spectrum antibiotics used in their place.

Make An Appointment Today

To learn more about allergy and immunology services at First Physicians Group, click here.

To schedule an appointment with Dr. Trickett, click here.

Related Reading

Nothing To Sneeze At: The latest in allergy testing and immunotherapy cures

Penicillin Allergy FAQ

Written by Sarasota Memorial copywriter Philip Lederer, MA, who crafts a variety of external communications for the healthcare system. SMH’s in-house wordsmith, Lederer earned his Master’s degree in Public Administration and Political Philosophy from Morehead State University, KY, and is allergic to wasps and anything before 6am.