There are several reasons a cough may be persisting. The explanation could be as simple as allergies or a lingering infection, but it could also be more serious. It’s important to get to the bottom of the cause and take steps to keep your condition from getting worse.
If you have a cough that has lasted eight weeks or longer, chances are you have what is known as a “chronic cough.” That means that your cough is likely not caused by a simple respiratory infection or cold, so trying to ignore it won’t make it go away.
More than a nuisance, a chronic cough is an actual medical diagnosis that needs attention, and you should see a healthcare provider to determine what is causing it and how to treat it.
Possible Causes and Treatments
The causes of a chronic cough can range from easily treatable to some concerns that are far more serious. Treatment depends on the underlying cause. These include :
- Postnasal drip – Also called upper airway cough syndrome, postnasal drip is a common cause of a persistent cough. Allergies, viruses, dust, chemicals, or inflammation can irritate your nasal membranes and trigger runny mucus that drips out of your nose and down your throat. This makes you cough, especially at night when you lie down.
A cough related to postnasal drip may improve with the use of a decongestant, nasal or oral antihistamine, nasal glucocorticoid, or nasal spray. The best treatment (or combination of treatments) depends upon your symptoms and medical history. - Asthma – When you have asthma, the muscles around your airways tighten, the lining of your airways swell, and the cells in your airways produce thick mucus. An asthma cough is your body’s way of trying to get air into those restricted areas. Asthma can be triggered by weather, allergies, infections, tobacco smoke, medications, and even exercise and emotions. If this is what’s triggering your cough, you will likely be given the standard treatment for asthma, which includes an inhaled glucocorticoid to decrease inflammation of the airways. If you are also experiencing wheezing or shortness of breath, you may be prescribed an inhaled bronchodilator to open up the airways.
- Infections – Even after you seem to have recovered from your cold, flu, COVID-19 infection, or pneumonia is gone, the cough may linger. Pertussis, or whooping cough, is a respiratory tract infection and can be an under-the-radar cause of chronic cough. While it is usually covered in childhood immunizations, the CDC recommends that all adults aged 19 and over should get a pertussis booster as a Tdap shot. Your doctor can measure your immunity with a blood test.
Many infections may simply need to run their course. It takes time for your lungs to heal and create new cough receptors. But in some cases, your clinician may prescribe an antibiotic. - Gastroesophageal Reflux Disease (GERD) – With 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. The acidic fumes coming from your stomach can irritate your lungs, triggering a chronic cough. Heartburn and chest pain are common symptoms of GERD, though you may not have any symptoms besides the cough.
It’s possible you may have to make some lifestyle changes to get relief. These include avoiding substances that increase reflux, such as high-fat foods, chocolate, colas, red wine, acidic juices, and excessive alcohol. Your clinician may ask you to lose weight or stop smoking. You may be given a medication to slow the production of acid in your stomach, called a proton pump inhibitor. It may take several weeks of treatment before you see results. If your cough does not improve during this time, further testing may be recommended. - Blood Pressure Drugs – Angiotensin converting enzyme (ACE) inhibitors, which are commonly used to treat high blood pressure, may cause a chronic dry, hacking cough in up to 20 percent of patients.
This can usually be remedied with a slight change in medication. - Smoking – Smoking damages your lungs (and the rest of your body). Your lungs make mucus to try to get rid of chemicals and particles in tobacco smoke that irritate them. This is what is often referred to as the “smoker’s cough.” It can also be among the first signs of a much bigger problem, such as chronic obstructive pulmonary disease (COPD).
You should stop smoking but do not expect the cough to clear up right away or at all. Years of smoking mean your lungs will take time to try and repair themselves. - Chronic obstructive pulmonary disease (COPD) – COPD is a group of diseases including emphysema, chronic bronchitis, and chronic obstructive asthma that make it hard to get air in and out of your lungs. 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. Most people who have COPD are smokers or used to be. But it’s possible to have COPD and to never have smoked.
COPD may require treatment with rescue inhalers and inhaled or oral steroids to help control symptoms and minimize further damage. It may also require the use of oxygen therapy. - Lung cancer – Although this shouldn’t be at the top of your list of possible causes, it’s another reason to get your cough checked out. Smoking, by far, is the top cause of lung cancer, although many people who never smoked have had lung cancer. If you’re a nonsmoker and don’t have a family history of lung cancer, it’s not the likely diagnosis. 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.
Treatment is determined by the size and location of the cancer and may require surgery, chemotherapy, radiation therapy, targeted drug therapy, and immunotherapy.
If the cause of your cough cannot be determined and it continues to persist (called a refractory cough ), a medication that suppresses coughs may be recommended. These include both prescription and nonprescription options. Do not continue to take non-prescription medications for extended periods of time without consulting your health care provider again.
Diagnosing the cause of a chronic cough
To get to the underlying cause of your cough, your clinician will take your medical history and conduct a physical examination. They’ll want to know things like:
- When did the cough start?
- Is there something that seems to trigger it?
- Do you cough up any phlegm, mucus, or blood?
Have you been in close contact with anyone who has similar symptoms or may have had some sort of respiratory infection such as a cold, pneumonia, COVID-19, tuberculosis, or whooping cough? - Do you smoke or have you in the past?
- Do you have trouble with heartburn or indigestion?
- Do you have any allergies or have experienced postnasal drip?
- Have you started taking any new medications recently?
They will take your vital signs including your temperature, listening to your lungs and heart with a stethoscope. Based on your symptoms, your provider may suggest a trial treatment before conducting further tests. If your cough improves, then you shouldn’t need further testing.
However, if your cough persists, or if your diagnosis is not clear, you may need further testing. Further tests might include:
- Throat swab – Usually done with a long cotton swab to take a culture and test for infection.
- Blood test – This could help tell if your body is fighting an infection.
- Chest X-Ray – a chest X-ray or even a chest CT scan may be performed, especially If you smoke or are used to smoke, or if you have other medical conditions that can affect your lungs.
- Lung function tests – your clinician may try to measure the pattern of airflow into and out of the lungs. This includes conducting a spirometry (you’ll breathe out hard and fast into a small plastic device to measure how well you breathe out air) or a methacholine challenge test (also known as bronchoprovocation test) to evaluate how “reactive” or “responsive” your lungs are.
- Acid reflux testing — Acid in your esophagus may trigger coughing. Also called a pH probe, this test is done to measure the level of acid in the fluid in your esophagus. A test called an upper endoscopy may be done in some cases to look for irritation of the esophagus and to obtain a biopsy of the esophagus.
When to Call Your Doctor
After around 8 weeks, if your cough hasn’t gone away, you should see a health care provider. Coughs associated with allergies or even a common cold can last months, but they should not be ignored.
Call sooner if you have other symptoms such as shortness of breath or fever If you’re coughing up blood, seek help immediately.