Nearly one million children with asthma are prescribed antibiotics yearly, according to a study from Penn State College of Medicine. This goes against the current medical consensus, which sees no benefit from asthmatics taking antibiotics.

Neither U.S. nor international guidelines recognize antibiotics as an appropriate treatment for asthma. Yet many doctors do prescribe them. The Penn State study found this occurring in about one of every six doctor visits by a child for asthma, in the absence of any known infection.

The study also found that antibiotics were prescribed more often during asthma visits to primary care doctors than to emergency department doctors.

Unnecessary antibiotic prescriptions help breed antibiotic-resistant bacteria and often cause side effects in the people who take them.

The study was not designed to reveal why doctors are prescribing antibiotics to children with asthma. What it looked for was the frequency of these prescriptions and what factors seem to make doctors more or less likely to prescribe antibiotics.

The most encouraging finding was that when doctors took the time to educate the patient about asthma – its causes, triggers and how best to minimize its symptoms – antibiotics were much less likely to be prescribed. When asthma education was part of the doctor visit, antibiotics were prescribed 11% of the time; when it wasn't, the rate was 19%.

The study looked at two national databases of office and emergency department asthma visits made by children 18 years or younger during the 10 year period 1998-2007. Only visits where the children did not have a known infection were included in the study. There were 5,198 such visits recorded in the databases, which gave an estimate of one million such visits occurring nationwide every year. During 15.6% of these visits, antibiotics were prescribed.

The study also found that antibiotics were prescribed more often during asthma visits to primary care doctors than to emergency department doctors. And patients were more likely to be prescribed antibiotics if they also received a prescription for inhaled corticosteroids or if the visit occurred during winter.

The researchers speculate that patient requests for antibiotics are not fueling the large number of prescriptions; it's doctors who are responsible. They further speculate that this may be come from doctors' desire to cover all possible treatment bases when faced with diagnostic uncertainty — symptoms that are likely due to asthma but may be due to other causes, such as undiagnosed atypical pneumonia.

While these are speculations, the fact that asthma patients are frequently prescribed antibiotics is not. And the problem doesn't seem to be unique to the U.S. A recent Belgian study that looked at prescription records found that Belgian children prescribed an asthma drug were twice as likely to be prescribed antibiotics as other children were. In that study, over one-third of all children who received an asthma drug were dispensed an antibiotic on the same day.

Articles on both the U.S. and Belgian studies were published online ahead-of-print by the journal Pediatrics on May 23, 2011 and will appear in a future print edition of the journal.