Pregnant and Allergic to Penicillin? Why Testing Is Important
Why do people think they’re allergic to penicillin?
Many who believe they are allergic to penicillin have been avoiding the medication class since they were children. Penicillin is a typical treatment for common childhood infections, including ear infections, strep throat, and pneumonia. But, for many children, what’s thought to be a reaction to the medication—often a minor rash—is actually caused by the infection itself, Dr. Kwah says.
And for many of those kids who get a flat, red rash as a reaction to the medication, it turns out to be a one-time problem that never happens again.
“We have studies showing that for 80% of those who did have a reaction once, indicating an actual allergy, it is gone after 10 years,” Dr. Kwah says. “We don’t know if it means someone was allergic and outgrew it, or if the immune system has simply changed over time.”
How penicillin allergy testing works
Penicillin allergy testing for pregnancy is usually done in the third trimester. The procedure involves a little needle poke, which allows extracts of penicillin to be placed just under the skin.
“If a rash doesn’t appear within 15 to 20 minutes, we do another, deeper poke. If there’s no rash within that additional 15 to 20 minutes, we know that there is over a 95% chance of no penicillin allergy,” Dr. Kwah says. “One final step is to give the patient an oral dose of amoxicillin, a form of penicillin, in the office and make sure there is still no reaction.”
Dr. Kwah says penicillin allergy testing has been safely performed in pregnant women for many years. “As allergists, we are very protective of pregnant women; this testing has been very well-studied and is something we feel very confident about,” he says.
Meanwhile, national organizations are paying attention. For instance, the American College of Obstetricians and Gynecologists recently updated its guidelines to recommend penicillin allergy testing in all pregnant women with a reported allergy.
Dr. Son says that the Yale program has been receiving many referrals since it began. “Our OBs are excited about it. An allergist can perform a thorough evaluation and testing to better understand whether there is a real issue,” she says.
Benefits of penicillin allergy testing are broad
In addition to eliminating personal anxiety, clearing a woman of a penicillin allergy is helpful on a broader level, too, Dr. Kwah adds.
“Use of a very broad antibiotic means you are more likely to become infected with a bug that is resistant to many different drugs,” he says. “And you are potentially creating a situation where a bad bug can evade antibiotics, proliferate, and become more prevalent in the community.”
At the end of the day, being able to remove the words “penicillin allergy” from a medical history can be liberating for patients, he adds. “You don’t even have to talk about it anymore—or worry. We love to see that impact happen in real time,” he says.
