Why Won’t Your Cough Go Away After a Cold? Doctors Explain

Doctors are weighing in on what's really behind a cough that refuses to leave, and why it tends to flare up just as you're trying to get some sleep. As for a quick fix, the answer may call for more patience than you'd like.

The muscle aches are gone and your stuffy nose has finally cleared, but that nagging cough just won't quit. Even after the infection itself is over, a cough can hang around long after the rest of the illness has left your system.

It's more common than you might think. "About 1 in 4 people who have had a cold or other respiratory infection will have a lingering cough," Aline M. Holmes, an associate professor at Rutgers University School of Nursing, says.

A 2024 article in the Canadian Medical Association Journal backs that up. Its authors cite statistics showing that roughly 11 to 25 percent of adults develop a post-infectious cough after a respiratory infection, with symptoms lasting anywhere from three to eight weeks.

Omid Mehdizadeh, MD, a laryngologist and ear, nose, and throat specialist, says this type of cough, sometimes referred to as a post-viral cough, often shows up in the wake of a viral infection in the airways, like the common cold.

"A post-viral cough is typically due to increased inflammation of the respiratory system, including the nose, throat, voice box, and lungs," Mehdizadeh explained.

Dr. Thomas Russo, a professor and infectious disease expert at the University at Buffalo in New York, adds that respiratory illnesses usually have what doctors call an "acute" phase, which is what most people think of as the infection itself.

Once that phase passes, the body enters a slower stage of winding down and healing, which explains why recovery can feel like a gradual climb. According to Dr. Russo, the end of the acute phase rarely means you're instantly back to your old self, as getting back to full strength can take a while.

If the cough sticks around after you feel better, it may simply be "residual inflammation" while your damaged airway tissue heals, he says.

That cough may be annoying, but it serves a purpose. "Coughing is protective. It removes irritants from the lungs and protects the airway," Dr. Jonathan Parsons, a pulmonologist at the Ohio State University Wexner Medical Center, says.

The good news is that this leftover inflammation "is not necessarily a sign the infection is active or persistent," Dr. Parsons says.

Postnasal drip that outlasts the illness can also keep a cough going, Holmes adds.

"If you have a postnasal drip, that mucus can be very irritating to your throat," she says. "It's a result of your body still working to clear your lungs and upper respiratory tract of mucus, which can take some time, even if you are otherwise okay."

Holmes notes that these coughs tend to be at their worst after dark, since lying flat lets mucus trickle down the back of the throat toward the lungs, which triggers the urge to cough. "That makes it difficult to get any rest," she says.

So what can you do about it? Unfortunately, not much beyond riding it out. Family physician Dr. Kevin Liang, one of the authors of the Canadian Medical Association Journal article, shared what the research shows.

"We look at evidence all the way from asthma puffers, to some of that over-the-counter medications to codeine, and it really shows none of these work effectively. Then in trials that have run, most patients with post-infectious cough, have their cough resolved on their own without any treatments at all," he said.

In other words, time and patience are often the best medicine. That said, there are ways to make the wait a little easier. Chantel Strachan, MD, a primary care physician and internist at Columbia University Irving Medical Center, recommends a gentle approach.

"Offering conservative treatment for this cough can help to minimize this," Dr. Strachan says. "Conservative treatments include over-the-counter cough suppressants, over-the-counter intranasal steroids for post nasal drip, humidifiers, and lozenges."