One million U.S. kids with asthma are prescribed unnecessary antibiotics each year—and that could increase the spread of antibiotic-resistant infections, according to study findings published in the journal Pediatrics and reported by Reuters Health.

For the study, researchers checked information from national surveys about the doctor visits of asthmatic children with no declared signs of an infection requiring antibiotic treatment. Scientists found that  during 1 in 6 of these visits, doctors prescribed the kids an antibiotic anyway.

But is a child’s wheezing asthma a sign of an infection? Unless a child has symptoms of an infection, official guidelines tell doctors not to include antibiotics as part of treatment for kids already diagnosed with asthma. The new study from Penn State College of Medicine showed that many doctors didn’t follow these guidelines.

What’s more, another study published in the same issue of Pediatrics supported these research findings. Scientists in Belgium found that children taking asthma drugs are almost twice as likely as other kids to receive antibiotics.

Why is this a problem? Well, experts agree that antibiotic overuse can cause increased bacterial resistance.

Doctors could be over-prescribing antibiotics “out of fear, out of habit,” offered Kris De Boeck, MD, the Belgian study author. In addition, De Boeck said parents could be adding to the problem. “Some physicians state that parents do not want to leave the consultation room before they get a medicine.”

Click here to read more about other illnesses in children that pediatrics commonly misdiagnose.