Common colds and viral infections typically clear up in seven to 10 days. But for one in four adults, a cough can stick around long after other cold symptoms clear up. It may leave you wondering if you should seek medical care, whether you’re still contagious or if there’s an underlying issue.
“It can take the body time to clear out inflammation that occurs from an upper respiratory infection,” says Russell Buhr, MD, PhD, a UCLA Health pulmonary and critical care physician. “But being proactive and knowing what to expect can put your mind at ease.”
What causes a lingering cough after a cold?
Coughs that persist after a common cold or other upper respiratory infection are called post-infectious or post-viral coughs. They can linger for three to eight weeks after a viral infection.
There are two common causes of a post-viral cough in adults:
- Postnasal drip, when mucus drains into your throat
- Inflammation, or swollen airways, related to the initial respiratory infection
Postnasal drip during the day can irritate your throat and vocal cords. But Dr. Buhr says nighttime makes it much worse. “When you’re lying flat at night, mucus runs down the back of your throat and into your lungs,” he says. “It can cause chest congestion that needs to be coughed up. When mucus travels down your throat, it can also cause irritation and inflammation, making you cough.”
Most coughs following an upper respiratory infection are caused by the infection itself. But in some cases, the persistent cough may be a symptom of pre-existing asthma (made worse on by the recent virus) or a secondary infection that took hold while your immune system was distracted.
When to seek medical care for a post-viral cough
Cold-related coughs can last for up to eight weeks. The good news is that you’re typically only contagious for the first three to five days of the initial respiratory infection, says Dr. Buhr.
A lingering cough will usually clear up on its own as postnasal drip improves and inflammation decreases. But you should see your primary care physician (PCP) about a lingering cough if you develop what Dr. Buhr calls “red flag symptoms,” which include:
- Coughing up blood, or any change in the color, thickness or texture of the fluid or droplets your cough produces
- Increased frequency or strength of your cough
- Ongoing systemic symptoms, such as fever, body aches, chills, changes in appetite or difficulty swallowing
Dr. Buhr recommends that adults with heart or lung issues see their PCP with any upper respiratory infection, especially if it lingers. You may also want to make an appointment if, after a couple of weeks, your cough still interferes with your ability to sleep or go to work.
“Your symptoms shouldn’t worsen,” Dr. Buhr says. “You should see improvement over time.”
Other causes of persistent cough
Most of the time, when people seek medical care for an ongoing cough, it’s associated with a prior respiratory infection. But your health care provider may want to rule out other conditions that may be contributing to your symptoms.
“The first thing I ask adults when they present with a persistent cough is if they remember being sick right before the cough started,” Dr. Buhr says. “And probably 60% to 70% of the time, that cold or infection is the cause of the cough. But we want to ensure we’re not missing an alternative diagnosis.”
Other contributors to persistent cough include:
- ACE inhibitors (blood pressure medication)
- Asthma
- Congestive heart failure
- Gastroesophageal reflux disease (GERD)
- Lung cancer
- Pneumonia or bronchitis
- Smoking
“If you have other medical issues, especially asthma or reflux, a cold could act as a trigger,” Dr. Buhr says, “and both the cold and your pre-existing condition could be contributing to the cough.”
How to treat a persistent cough after a cold
During the first few weeks following a cold, you can treat lingering coughs with home remedies and over-the-counter (OTC) medication:
- Humidifiers provide extra moisture to help soothe throats and nasal passages. Hold a steaming cup of water or tea under your face for the same effect.
- OTC decongestants and nasal sprays reduce swelling and inflammation in your nose.
- OTC cough syrup is best used at night since it can cause drowsiness.
- Throat lozenges and cough drops stimulate your saliva production to soothe a sore throat. Lozenges containing menthol also help open nasal passages.
If your symptoms continue beyond a few weeks and nothing seems to be helping, your PCP may recommend a:
- Prescription nasal spray, for ongoing nasal drip that is not responding to OTC medication
- Steroid inhaler, to help clear residual inflammation in the lungs
