By Kathy Walsh

DENVER (CBS4) – You probably know someone who thinks he or she is allergic to penicillin. CBS4 Health Specialist Kathy Walsh took an unscientific survey on Denver’s 16th Street Mall.

Danita Roberts said, “I used to break out in hives.”

Daymean Probst told Walsh, “My mom told me when I was.”

And Darrin Gonzales explained, “My first allergic reaction would have been before I could physically remember it was.”

(credit: CBS)

(credit: CBS)

A fact sheet from the Centers for Disease Control and Prevention indicates 10 percent of U.S. patients report a penicillin allergy. And while some people may have had issues with the antibiotic in the past, experts say less than 1 percent of the entire population is truly allergic. The CDC estimates 80 percent of people lose their sensitivity to penicillin as they age.

“Even after 10 years, only 20 percent of the confirmed patients will still be allergic, so yes, it does look like you outgrow it,” said Dr. Rohit Katial with National Jewish Health.

Dr. Rohit Katial is interviewed by CBS4's Kathy Walsh (credit: CBS)

Dr. Rohit Katial is interviewed by CBS4’s Kathy Walsh (credit: CBS)

Katial is a professor of medicine and allergist and immunologist. He says misinformation about penicillin allergy can be a concern for patients.

“Forcing them into a different class of antibiotic (broader spectrum) that may be more potent could raise problems potentially,” Katial said.

Among those problems is killing bacteria you don’t need to kill and possible antibiotic resistance.

(credit: CBS)

(credit: CBS)

“You could develop resistance to the broader spectrum antibiotic and really, you want to reserve those for more severe infection,” said Katial.

There is penicillin testing, but Katial says the need to be tested depends on the individual. His advice is to ask your doctor.

Most people Walsh spoke with who believe they are allergic to penicillin said they don’t feel the need to get tested. Either they don’t get sick often or the other drugs they’ve been given over the years have worked.

Kathy Walsh is CBS4’s Weekend Anchor and Health Specialist. She has been with CBS4 for more than 30 years. She is always open to story ideas. Follow Kathy on Twitter @WalshCBS4.