Average cough lasts 18 days

Coughers, step away from the antibiotics.

A new study indicates that no matter how many antibiotics or cough medicines or throat lozenges you take, if you have a cold, your cough is likely to last 18 days.

Study author Mark Ebell, an associate professor at the University of Georgia College of Public Health, points out in his report that people tend to turn to their doctor for antibiotics after about a week because that’s how long they expect their cough to last. However, the researchers examined 19 earlier medical studies that showed the average duration of a cough is 17.8 days, with some showing coughs can last as long as four weeks.

A poll of 493 respondents commissioned by Dr. Ebell and his study colleagues showed that most believed a cough typically lasted between 6.5 and 9.2 days.

“If a patient expects that an episode of ACI [acute cough illness] should last about six or seven days, it makes sense that they might seek care for that episode and request an antibiotic after five or six days,” the report, published Monday in the Annals of Family Medicine, reads.

“Furthermore, if they begin taking an antibiotic seven days after the onset of symptoms, they may begin to feel better three or four days later, with the episode fully resolving 10 days later. Although this outcome may reinforce the mistaken idea that the antibiotic worked, it is merely a reflection of the natural history of ACI,” the report continued.

Antibiotics are often ineffective against coughs, which are often diagnosed as acute bronchitis or bronchiolitis, because, according to the United States Centers for Disease Control and Prevention, more than 90 per cent of such cases are viral, not bacterial so they do not respond to antibiotics. The CDC advises doctors to refer to acute cough illness as a “chest cold” rather than bronchitis to reduce patients’ expectations for antibiotics.

Educating people that their coughs may naturally last longer than they expect may be effective in cutting down the number of people requesting antibiotics from their physicians, Dr. Ebell said.

“It is therefore important that physicians emphasise the natural history of ACI with patients when they seek care for an episode of acute cough. Patients should be told it is normal to still be coughing two or even three weeks after onset and that they should only seek care if they are worsening or if an alarm symptom, such as high fever, bloody or rusty sputum, or shortness of breath, occurs,” Dr. Ebell said.

He added: “Our study confirmed that previous prescriptions of antibiotics increase the belief in their efficiency, creating the potential for a cycle of expectation and prescription.”

The researchers concluded: “We believe that education of the general public, the media, and physicians should emphasise appropriate expectations regarding the natural history of ACI in order to reduce inappropriate demands for antibiotics.”

Acute cough illness is one of the most common reasons patients seek medical attention, with more than 3 million outpatient visits in the US in 2006 for a chief complaint of cough and more than 4.5 million outpatient visits with a final diagnosis of “acute bronchitis or bronchiolitis”.

A poll of 493 respondents commissioned by Dr. Ebell and his study colleagues showed that most believed a cough typically lasted between 6.5 and 9.2 days.