What Causes Cough?

Conditions list medically reviewed by George Krucik, MD, MBA

A cough is a common reflex action that clears the throat of mucus or foreign irritants. Coughing to clear the throat is typically an infrequent action, although a number of conditions can cause more frequent bouts of coughing. In general, a cough... Read More

Cough basics

A cough is a common reflex action that clears the throat of mucus or foreign irritants. Coughing to clear the throat is typically an infrequent action, although a number of conditions can cause more frequent bouts of coughing.

In general, a cough that lasts for less than three weeks is an acute cough.

A cough that lasts between 3 and 8 weeks, improving by the end of that period, is a subacute cough.

A persistent cough that lasts more than eight weeks is a chronic cough.

Most cough episodes will clear up, or at least significantly improve, within two weeks. If you cough up blood or have a “barking” cough, talk to your doctor. Any cough that hasn’t improved after a few weeks may be serious, and you should see a doctor.

What causes a cough?

A cough can be caused by several conditions, both temporary and permanent.

Clearing the throat

A cough is a standard way of clearing the throat. When your airways become clogged with mucus or foreign particles such as smoke or dust, a cough is a reflex reaction that attempts to clear the particles and make breathing easier.

Usually, this type of coughing is relatively infrequent, but coughing will increase with exposure to irritants such as smoke.

Viruses and bacteria

The most common cause of a cough is a respiratory tract infection, such as a cold or flu. Respiratory tract infections are usually caused by a virus and may last from a few days to a week. Infections caused by the flu may take a little longer to clear up and may sometimes require antibiotics.

Smoking

Smoking is another common cause of coughing. A cough caused by smoking is almost always a chronic cough with a distinctive sound. It’s often known as “smoker’s cough.”

Asthma

A common cause of coughing in young children is asthma. Typically, asthmatic coughing involves wheezing, making it easy to identify. Asthma exacerbations should receive treatment using an inhaler. It’s possible for children to grow out of asthma as they get older.

Medicines

Some medications will cause coughing, although this is generally a rare side effect. Angiotensin-converting enzyme (ACE) inhibitors, commonly used to treat high blood pressure and heart conditions, can cause coughing. Two of the more common brands are Zestril (lisinopril) and Vasotec (enalapril). The coughing stops when the medication is discontinued.

Other conditions

Other conditions that may cause a cough include:

  • damage to the vocal cords
  • postnasal drip
  • bacterial infections such as pneumonia, whooping cough, and croup
  • serious conditions such as pulmonary embolism and heart failure 

Another common condition that can cause a chronic cough is gastroesophageal reflux disease (GERD). In this condition, stomach contents flow back into the esophagus. This backflow stimulates a reflex in the trachea, causing the person to cough.

Emergency issues

Most coughs will clear up, or at least significantly improve, within two weeks. If you have a cough that hasn’t improved in this amount of time, see a doctor, as it may be a symptom of a more serious problem.

If additional symptoms develop, such as a fever, chest pains, headaches, drowsiness, or confusion, contact your doctor as soon as possible.

Coughing up blood or having difficulty breathing require immediate emergency medical attention.

How is a cough treated?

A cough can be treated in a variety of ways, depending on the cause. For healthy adults, most treatments will involve self-care.

Self-treatment

A cough that results from a virus can’t be treated with antibiotics. You can, however, soothe it in the following ways:

  • Keep hydrated by drinking plenty of water.
  • Elevate your head with extra pillows when sleeping.
  • Use cough drops to soothe your throat.
  • Gargle hot salt water regularly to remove mucus and soothe your throat.
  • Avoid irritants, including smoke and dust.
  • Add honey or ginger to hot tea to relieve your cough and clear your airway.
  • Use decongestant sprays to unblock your nose and ease breathing.

Medical care

Typically, medical care will involve your doctor looking down your throat, listening to your cough, and asking about any other symptoms.

If your cough is likely due to bacteria, your doctor will prescribe oral antibiotics. You’ll usually need to take the medication for a week to fully cure the cough. They may also prescribe either expectorant cough syrups, or cough suppressants that contain codeine.

If your doctor can’t find a cause for your cough, they may order additional tests. This could include a chest X-ray to assess whether your lungs are clear, along with blood and skin tests if they suspect an allergic response. In some cases, phlegm or mucus may be analyzed for signs of bacteria or tuberculosis.

It’s very rare for a cough to be the only symptom of heart problems, but a doctor may request an echocardiogram to ensure that your heart is functioning correctly and isn’t causing the cough.

Difficult cases may require additional testing. A CT scan offers a more in-depth view of the airways and chest, and it can be useful when determining the cause of the cough. If the CT scan doesn’t show the cause, your doctor may refer you to a gastrointestinal (GI) specialist or a pulmonary (lung) specialist. One of the tests these specialists may use is esophageal pH monitoring, which looks for evidence of GERD.

In cases where the previous treatments are either not possible or extremely unlikely to be successful, or the cough is expected to resolve without intervention, doctors may prescribe cough suppressants.

What’s the outcome if left untreated?

In most cases, a cough will disappear naturally within a week or two after it first develops. A cough won’t typically cause any long-lasting damage or symptoms. 

In some cases, a severe cough may cause temporary complications such as:

  • tiredness
  • dizziness
  • headaches
  • fractured ribs

These are very rare, and they will normally cease when the cough disappears.

A cough that is the symptom of a more serious condition is unlikely to go away on its own. If left untreated, the condition could worsen and cause other symptoms.

What preventive measures can be taken to avoid a cough?

While infrequent coughing is necessary to clear the airways, there are ways you can prevent catching other coughs.

Quit smoking

Smoking is a common contributor to a chronic cough. It can be very difficult to cure a “smoker’s cough.” There are a wide variety of methods available to help you stop smoking, from gadgets such as electronic cigarettes to advice groups and support networks. After you stop smoking, you will be much less likely to catch colds or suffer from a chronic cough.

Dietary changes

A study in the American Journal of Respiratory and Critical Care Medicine found that people who eat diets high in fruit, fiber, and flavonoids are less likely to suffer from chronic coughs. If you need help adjusting your diet, your doctor may be able to advise you or refer you to a dietitian.

Medical conditions

It’s advisable to stay away from anyone suffering from contagious illnesses, such as bronchitis, to avoid coming into contact with germs. You should wash your hands frequently, and you shouldn’t share cutlery, towels, or pillows.

If you have existing medical conditions that increase your chances of developing a cough, such as GERD or asthma, consult your doctor about different management strategies. Once the condition is correctly managed, you may find that your cough disappears, or it may become much less frequent.

Medically reviewed by Daniel Murrell, MD on March 16, 2017Written by Kati Blake


92 possible conditions

This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Conditions list medically reviewed by George Krucik, MD, MBA