A lasting cough may be a sign of many things. Here’s why it may not be getting better and when to see a doctor to find out the cause and the treatment.
“Your nose is one of the first touch points between your body and the environment. Every infection and allergen, like dust mites and pollen, comes into it,” says Panagis Galiatsatos, MD, a pulmonary and critical care medicine doctor at the Johns Hopkins School of Medicine.
Also called upper airway cough syndrome, postnasal drip is a common cause of a persistent cough. When a virus, allergies, dust, chemicals, or inflammation irritate your nasal membranes, they make runny mucus that drips out of your nose and down your throat. This makes you cough, especially at night when you lie down.
“The most abundant cough receptors in your body are in the airways and around your vocal cords,” Galiatsatos says. “If anything gets in there, your body’s first response is to cough to get it out.”
Asthma is another common cause for chronic cough -- and not only in kids.
When you have asthma, the muscles around your airways tighten, the lining of your airways swells, and the cells in your airways produce thick mucus. The asthma cough is your body’s way of trying to get air into those restricted areas. It’s triggered by infections, weather, allergies, tobacco smoke, medications, and even exercise and emotions.
“During that time, the lungs heal and new cough receptors are made,” Galiatsatos says. He likens it to building a house. “You have to clear out the old stuff to put new stuff in. That’s what coughs do.”
Pertussis, or whooping cough, is a respiratory tract infection and an under-the-radar cause of chronic cough. Childhood immunizations usually cover it, but your resistance may wear down as you age. Galiatsatos notes that adults may need a booster. Your doctor can measure your immunity with a blood test.
Gastroesophageal Reflux Disease
How can a stomach condition be the source of your lingering cough? When you have gastroesophageal reflux disease, or GERD, a weak band of muscle around the lower part of your esophagus lets stomach acid return to your esophagus instead of sending it to your stomach.
“It doesn’t have to be a massive reflux in the back of your throat; it’s actually the acidic fumes in your stomach -- they’re really potent,” Galiatsatos says. “Those fumes constantly come out of your stomach and, when you breathe them in, they irritate your lungs.”
Blood Pressure Drugs
“ACE inhibitors for blood pressure often cause a chronic dry cough,” says David Hill, MD, clinical research director at Waterbury Pulmonary Associates in Waterbury, CT, and a volunteer medical spokesperson for the American Lung Association.
When Hill sees a patient who has a persistent cough and takes an ACE inhibitor, “it’s sort of an easy win,” he says. “With a slight change in medication, the cough almost always goes away.”
COVID-19 is the illness caused by SARS-CoV-2, the coronavirus that’s at the heart of the pandemic that started in 2020. When the virus makes people sick, it can cause lung inflammation and a dry cough, among many other symptoms that can range from mild to life-threatening.
“The prolonged cough from COVID-19 is no different than any other virus that affects your lungs,” Galiatsatos says. “The injured parts of your lungs are trying to clear out the infection and heal.”
Smoking damages your lungs (and the rest of your body). You may also have heard of the “smoker’s cough,” which happens because chemicals and particles in tobacco smoke irritate the lungs. The body makes mucus to try to get rid of it through coughing.
“Many smokers will not think of their daily productive cough as a chronic cough at all because they just assume it is normal to cough up phlegm,” Hill says in an email.
Chronic Obstructive Pulmonary Disease (COPD)
In most cases, your body makes too much mucus and coughs to try to clear it out. Other symptoms include shortness of breath. Over time, COPD can worsen and become life-threatening.
Chronic cough can be a sign of lung cancer, but there are many other things that could be causing your cough. “If you’re a nonsmoker, and don’t have a family history of lung cancer, it’s not the likely diagnosis,” Hill says.
Smoking, by far, is the top cause of lung cancer. But many people who never smoked have had lung cancer. So although this shouldn’t be at the top of your list of possible causes, it’s important to get it checked out.
If it is lung cancer, the location of the tumor may affect whether there’s a chronic cough. Your lungs include three parts: tissue, airways, and circulation. Only the airways have cough receptors, so if there’s a growth in other parts of the lungs, it may not trigger a cough.
When to Call Your Doctor
“I don’t call anything a chronic cough until it’s been there 3 months,” Hill says. “An allergy cough can last months, as can a cough from a common cold. Everyone’s had a cold at some point where they just kept coughing. A lot of it just has to run its course.”
But don’t wait that long to tell your doctor what’s going on. Do that around 3-4 weeks if your cough hasn’t gone away. Call sooner if you have other symptoms such as shortness of breath, fever, or if you’re coughing up blood.