Trying to kick a nagging cough? It often just takes patience and time, physicians say

A niggling, nagging cough. They're unpleasant, aggravating and — unfortunately — all too common after various viral infections.

Research suggests "post-infectious cough," referring to symptoms lasting between three and eight weeks, impacts up to a quarter of adults after an initial respiratory infection like a cold, flu or COVID. 

So how do you kick that kind of lingering cough for good?

In many cases, it's just a matter of patience and time, suggest a trio of physicians in an article published in the Canadian Medical Association Journal (CMAJ) on Monday.

"Most of the time the cough will resolve on its own without any medication or treatment, but it can last a lot longer than you think," said one of the article's authors, Vancouver-based family physician Dr. Kevin Liang, in an interview with CBC News.

Liang, a clinical instructor in the department of family practice at the University of British Columbia, said patients often seem worried about their long-lasting coughs, thinking they still have their initial infection.

But that's usually not the case, he stressed.

What's actually happening is that a preceding infection triggers an "inflammatory cascade," Liang and his colleagues wrote, which then increases bronchial sensitivity and mucus production, while reducing mucus clearance.

In other words: Inflammation leads to more snot in your nose and more sensitivity in parts of your lungs, and that combo causes your body to cough — over and over.

And there's no quick fix, Liang said.

The question of how to combat an irksome cough is an old one.

For years, physicians divided up coughs into two categories: Acute, as in short-term, and chronic, referring to any cough lasting beyond a few weeks. But more recently, guidance started to shift toward a third category of "subacute" coughs that last just three to eight weeks — short enough to resolve, but long enough to be highly annoying.

One study, published nearly two decades ago, evaluated nearly 200 patients with lingering coughs, and found the most common cause of a "subacute" cough was simply a prior infection, not a more serious, ongoing health issue.

That's the same conclusion in the new CMAJ article. But the Canadian physicians' peer-reviewed practice suggestions also stressed that it's important for clinicians to consider other possibilities.