Researchers in the U.S. state of Georgia wrote in the Annals of Family Medicine that survey respondents tended to expect their cough to be gone in about a week, but a review of cough studies shows the hacking takes about three weeks to clear up.

The team, led by Mark Ebell from the University of Georgia in Athens, said they were concerned that patients' unrealistic expectations could lead them to ask doctors for antibiotics that won't speed their recovery, but will fuel drug resistance, cost money and increase the risk of side effects.

"Efforts to reduce inappropriate antibiotic use should target this discrepancy," the authors wrote, referring to unrealistic patient expectations.

"We're not trying to discourage people from getting care if they feel they need it, but at the same time we want to give them the confidence to give themselves care in situations when it's appropriate," said Ebell.

For the study, Ebell and his colleagues did a telephone survey of 493 adults in George about how long they'd expect a cough to last based on a hypothetical situation: if they had a 100.5 degree Fahrenheit (38 degree Celsius) fever and were bringing up yellow mucous.

Overall, people said they'd expect the cough to take between 7 and 9 days to clear up.

The team then reviewed 19 previous studies on severe coughs that recorded how long the condition actually lasted. In those studies, it took a cough - on average - 17.8 days to subside.

"I think it is important to understand that if you do get a cough you're probably going to be coughing for about three weeks," said Jeffrey Linder, who was not involved in the study but has done similar research.

"Also, there is evidence out there that getting an antibiotic at any point in the course is not going to make it shorter," added Linder, an associate professor at Brigham and Women's Hospital and Harvard Medical School in Boston.

According to the researchers, about 50 percent of patients with an acute cough in 2006 were prescribed an antibiotic. But most respiratory infections are caused by viruses, while antibiotics only affect bacteria.

Ebell said that patients should call their doctors if they bring up blood when they cough or are short of breath, while Linder said they should also do so if their cough lasts longer than a month or gets worse.

"There are over-the-counter things I recommend to people to feel better, but the main treatment is time," he said.

Source: bit.ly/Y5HGHi

(Reporting from New York by Andrew Seaman at Reuters Health; editing by Elaine Lies)

• A Permanent Economic Emergency