Unrealistic expectations of how long a cough should last might be contributing to inappropriate antibiotic use, a new study suggests.

The study, published in the latest edition of the Annals of Family Medicine, looked at acute cough illness, commonly called a chest cold. It found that people expected their cough to ease in six to nine days. Yet research pegs the average duration of the cough at 17.8 days.

The authors hypothesize that this gap between expectations and reality prompts people to go to the doctor and ask for antibiotics.

Acute cough illness, which is typically caused by viruses, is one of the most common reasons that patients seek care, the study says. There were more than 3 million outpatient visits in 2006 in which the chief complaint was a cough. Yet the rate of antibiotic prescriptions the same year for the cough was 50 percent. Antibiotics are effective only on bacterial infections, not viruses.

The study calls for further educating physicians and the general public about the viral nature of most chest colds.

— Heidi Hagemeier, The Bulletin