Have you ever had a cold but then been plagued by a continuing cough for weeks after you’ve recovered from all of your other symptoms?
This phenomenon is quite common, according to the authors of an article published on February 12, 2024, in the Canadian Medical Association Journal.
They cite statistics showing that around 11%–25% of all adults will experience a post-infectious cough after having a respiratory infection.
Symptoms can last between three to eight weeks, they say.
Why a cough can hang around after an infection
According to Omid Mehdizadeh, MD — an otolaryngologist (ENT) and laryngologist at Providence Saint John’s Health Center in Santa Monica, California — a post-infectious cough, also known as a post-viral cough, can occur after you have a respiratory tract infection caused by a virus, such as 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.
Per the article’s authors, this inflammation can lead to increased sensitivity of the bronchial tubes and increased mucus production, while decreasing mucus clearance at the same time.
UCLA Health notes that inflammation can cause the airways to swell, while draining mucus (postnatal drip) can irritate the throat and vocal cords. Both of these factors can contribute to a post-infectious cough.
What to do if you have a post-infectious cough
Chantel Strachan, MD, Primary Care Physician and Internist at Columbia University Irving Medical Center, said one residual effect of the COVID-19 pandemic is a stigma surrounding having a prolonged cough.
However, she stated that a post-infectious cough is benign, so it’s usually nothing to worry about, although it can be physically disturbing and a social nuisance.
“Offering conservative treatment for this cough can help to minimize this,” she said. “Conservative treatments include over-the-counter cough suppressants, over-the-counter intranasal steroids for post nasal drip, humidifiers, and lozenges.”
Strachan added that no evidence supports the use of antibiotics or steroids to help with a post-infectious cough.
Per the report, most trials found that people’s coughs improved over time without medication.
The authors also noted other reasons why it might be a good idea to avoid medicating post-infectious coughs.
The metered-dose inhalers used to deliver these medications give off greenhouse gases and can place a burden on the medical supply chain if they are prescribed off-label for post-infectious cough, they explained.
How to know if your cough is something more serious
Mehdizadeh said that one way to distinguish a post-infectious cough from something more serious is the fact that a post-infectious cough is typically a dry, hacking cough.
“A wet cough, which is associated with shortness of breath or chest pain, should be evaluated,” he noted.
“Other symptoms which should prompt evaluation include blood in the mucous, difficulty swallowing, pain, fever, difficulty breathing, and noisy breathing,” said Mehdizadeh.
According to the authors of the article, symptoms like these would indicate the need for a chest x-ray.
Other red flags that might indicate a problem include a history of recurrent pneumonia or long-term smoking.
Having a cough for longer than eight weeks is also a potential indicator of trouble. At this point, it is deemed to be a chronic cough, and a pulmonary function test to rule out asthma or COPD (chronic obstructive pulmonary disease) would be in order.
Takeaway
Having a cough following a respiratory infection such as the common cold is quite common, affecting 11% to 25% of adults.
A post-infectious cough occurs because of inflammation and swelling in a person’s airways. Postnasal drip due to increased mucus production also contributes.
Symptoms should clear up after about three to eight weeks. No prescription treatments are necessary, although over-the-counter medications can help ease your symptoms.
However, if your symptoms last longer than eight weeks or you have other red-flag symptoms such as a wet cough, bloody mucus, shortness of breath, chest pain, fever, or problems swallowing, you should see a doctor for evaluation.