Jan.  14, 2013 — Just how long should that pesky cough last?

The answer, according to most doctors, is close to 18 days. Yet many people with a cough get antsy after about five to nine days, a new study shows.

“Coughs last for longer than we think they do,” says researcher Mark H. Ebell, MD, a family doctor at the University of Georgia in Athens. “People think it should be over in a little over a week, but the reality is that a cough is more likely to last two weeks.”

In the study, researchers asked 500 adults from Georgia how long a cough should last in different situations,  such as with a fever or without. They compared these answers to those found in the medical literature.

Bottom line: There is a disconnect between how long people think a cough should last and how long it actually does. The findings appear in the January/ February issue of the Annals of Family Medicine.

Antibiotics Don’t Help Most Coughs

People in the study who had previously taken antibiotics for a cough were more likely to believe that antibiotics are always helpful for cough. But antibiotics don’t treat viruses, and using them when they are not needed can lead to antibiotic resistance.

Although people who received antibiotics for a cough due to a cold virus after seven days may feel better, it is often just the cough getting better on its own. “People may think it worked, but it is really just the natural history,” Ebell says.

Still, there are some red flags that a cough may be caused by something more serious than a virus.

These include coughs accompanied by:

• Brown or bloodied sputum
• Fever
• Chills
• Body aches
• Sudden onset of symptoms
• Shortness of breath
• Wheezing
• Hoarseness
• Trouble swallowing

People with chronic lung diseases such as asthma should also take their coughs more seriously.

“Coughs lasting 10 days or thereabouts are pretty normal,” says Henry Milgrom, MD. He is a professor of pediatrics at National Jewish Health in Denver.  Still, he says, “we don’t want to miss something that is infectious and treatable. Somebody who has a cough that is productive and a fever may have pneumonia or sinusitis or another treatable infectious disease that we would want to address quickly.”

In this scenario, don’t waste time, he says. But “if you are getting over a cold, have no fever, and no underlying lung disease, a cough can safely last for weeks.”

Whatever you do, don’t ask for antibiotics unless you think your cough is caused by a bacterial infection, says Len Horovitz, MD. He is  a pulmonary and internal medicine specialist at Lenox Hill Hospital in New York City. “They don’t help acute coughs, and if you take them too frequently, they won’t work when you really need them.”