A cough is your body’s natural reflex to help clear your airways of irritants and prevent infection. Common irritants include smoke, mucus, or allergens such as pollen, mold, or dust. Some medical conditions or medicines irritate the nerve endings in your airways and cause coughing.

A cough may be acute, subacute, or chronic depending on how long it lasts.

  • Acute coughs last less than three weeks and usually are caused by the common cold or other infections such as sinusitis or pneumonia.
  • Subacute coughs last three to eight weeks and remain after the initial cold or respiratory infection is over.
  • Chronic coughs last more than eight weeks and can be caused by gastroesophageal reflux disease (GERD), postnasal drip from sinus infections or allergies, or chronic lung conditions such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and interstitial lung diseases.

Your doctor will consider your medical history, physical exam, and test results when diagnosing and treating cough. Quitting smoking and avoiding smoke, other irritants, or certain medicines may help relieve your cough. Medicines to control coughing are usually used only for coughs that cause extreme discomfort or interfere with sleep. Talk to your doctor about how to treat your child’s cough.

Causes of Cough

Coughing occurs when the nerve endings in your airways become irritated. Certain irritants and allergens, medical conditions, and medicines can irritate these nerve endings.

Irritants and Allergens

An irritant is something you're sensitive to. For example, smoking or inhaling secondhand smoke can irritate your lungs. Smoking also can lead to medical conditions that can cause a cough. Other irritants include air pollution, paint fumes, or scented products like perfumes or air fresheners.

An allergen is something you're allergic to, such as dust, animal dander, mold, or pollens from trees, grasses, and flowers.

Coughing helps clear your airways of irritants and allergens. This helps prevent infections.

Medical Conditions

Many medical conditions can cause acute, subacute, or chronic cough.

Common causes of an acute cough are a common cold or other upper respiratory infections. Examples of other upper respiratory infections include the flu, pneumonia, and whooping cough. An acute cough lasts less than 3 weeks.

A lingering cough that remains after a cold or other respiratory infection is gone often is called a subacute cough. A subacute cough lasts 3 to 8 weeks.

Common causes of a chronic cough are upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD). A chronic cough lasts more than 8 weeks.

"UACS" is a term used to describe conditions that inflame the upper airways and cause a cough. Examples include sinus infections and allergies. These conditions can cause mucus (a slimy substance) to run down your throat from the back of your nose. This is called postnasal drip.

Asthma is a long-term lung disease that inflames and narrows the airways. GERD is a condition in which acid from your stomach backs up into your throat.

Other conditions that can cause a chronic cough include:

  • Respiratory infections. A cough from an upper respiratory infection can develop into a chronic cough.
  • Chronic bronchitis. This condition occurs if the lining of the airways is constantly irritated and inflamed. Smoking is the main cause of chronic bronchitis.
  • Bronchiectasis. This is a condition in which damage to the airways causes them to widen and become flabby and scarred. This prevents the airways from properly moving mucus out of your lungs. An infection or other condition that injures the walls of the airways usually causes bronchiectasis.
  • COPD (chronic obstructive pulmonary disease). COPD is a disease that prevents enough air from flowing in and out of the airways.
  • Lung cancer. In rare cases, a chronic cough is due to lung cancer. Most people who develop lung cancer smoke or used to smoke.
  • Heart failure. Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Fluid can build up in the body and lead to many symptoms. If fluid builds up in the lungs, it can cause a chronic cough.

Medicines

Certain medicines can cause a chronic cough. Examples of these medicines are ACE inhibitors and beta blockers. ACE inhibitors are used to treat high blood pressure (HBP). Beta blockers are used to treat HBP, migraine headaches, and glaucoma.

Who Is At Risk?

People at risk for cough include those who:

  • Are exposed to things that irritate their airways (called irritants) or things that they're allergic to (called allergens). Examples of irritants are cigarette smoke, air pollution, paint fumes, and scented products. Examples of allergens are dust, animal dander, mold, and pollens from trees, grasses, and flowers.
  • Have certain conditions that irritate the lungs, such as asthma, sinus infections, colds, or gastroesophageal reflux disease.
  • Smoke. Smoking can irritate your lungs and cause coughing. Smoking and/or exposure to secondhand smoke also can lead to medical conditions that can cause a cough.
  • Take certain medicines, such as ACE inhibitors and beta blockers. ACE inhibitors are used to treat high blood pressure (HBP). Beta blockers are used to treat HBP, migraine headaches, and glaucoma.

Women are more likely than men to develop a chronic cough.

Diagnosis of the Cause of Cough

Your doctor will diagnose the cause of your cough based on your medical history, a physical exam, and test results.

Medical History

Your doctor will likely ask questions about your cough. He or she may ask how long you've had it, whether you're coughing anything up (such as mucus, a slimy substance), and how much you cough.

Your doctor also may ask:

  • About your medical history, including whether you have allergies, asthma, or other medical conditions.
  • Whether you have heartburn or a sour taste in your mouth. These may be signs of gastroesophageal reflux disease (GERD).
  • Whether you've recently had a cold or the flu.
  • Whether you smoke or spend time around others who smoke.
  • Whether you've been around air pollution, a lot of dust, or fumes.

Physical Exam

To check for signs of problems related to cough, your doctor will use a stethoscope to listen to your lungs. He or she will listen for wheezing (a whistling or squeaky sound when you breathe) or other abnormal sounds.

Diagnostic Tests

Your doctor may recommend tests based on the results of your medical history and physical exam. For example, if you have symptoms of GERD, your doctor may recommend a pH probe. This test measures the acid level of the fluid in your throat.

Other tests may include:

  • An exam of the mucus from your nose or throat. This test can show whether you have a bacterial infection.
  • A chest x ray. A chest x ray takes a picture of your heart and lungs. This test can help diagnose conditions such as pneumonia and lung cancer.
  • Lung function tests. These tests measure how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs deliver oxygen to your blood. Lung function tests can help diagnose asthma and other conditions.
  • An x ray of the sinuses. This test can help diagnose a sinus infection.

Treatments for Cough

The best way to treat a cough is to treat its cause. However, sometimes the cause is unknown. Other treatments, such as medicines and a vaporizer, can help relieve the cough itself.

Treatment of Acute and Subacute Cough

An acute cough lasts less than 3 weeks. Common causes of an acute cough are a common cold or other upper respiratory infections. Examples of other upper respiratory infections include the flu, pneumonia, and whooping cough. An acute cough usually goes away after the illness that caused it is over.

A subacute cough lasts 3 to 8 weeks. This type of cough remains even after a cold or other respiratory infection is over.

Studies show that antibiotics and cold medicines can't cure a cold. However, your doctor may prescribe medicines to treat another cause of an acute or subacute cough. For example, antibiotics may be given for pneumonia.

Treatment of Chronic Cough

A chronic cough lasts more than 8 weeks. Common causes of a chronic cough are upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD).

"UACS" is a term used to describe conditions that inflame the upper airways and cause a cough. Examples include sinus infections and allergies. These conditions can cause mucus (a slimy substance) to run down your throat from the back of your nose. This is called postnasal drip.

If you have a sinus infection, your doctor may prescribe antibiotics. He or she also may suggest you use a medicine that you spray into your nose. If allergies are causing your cough, your doctor may advise you to avoid the substances that you're allergic to (allergens) if possible.

If you have asthma, try to avoid irritants and allergens that make your asthma worse. Take your asthma medicines as your doctor prescribes.

GERD occurs if acid from your stomach backs up into your throat. Your doctor may prescribe a medicine to reduce acid in your stomach. You also may be able to relieve GERD symptoms by waiting 3 to 4 hours after a meal before lying down, and by sleeping with your head raised.

Smoking also can cause a chronic cough. If you smoke, it's important to quit. Talk with your doctor about programs and products that can help you quit smoking. Also, try to avoid secondhand smoke.

Other causes of a chronic cough include respiratory infections, chronic bronchitis, bronchiectasis, lung cancer, and heart failure. Treatments for these causes may include medicines, procedures, and other therapies. Treatment also may include avoiding irritants and allergens and quitting smoking.

If your chronic cough is due to a medicine you're taking, your doctor may prescribe a different medicine.

Treating the Cough Rather Than the Cause

Coughing is important because it helps clear your airways of irritants, such as smoke and mucus (a slimy substance). Coughing also helps prevent infections.

Cough medicines usually are used only when the cause of the cough is unknown and the cough causes a lot of discomfort.

Medicines can help control a cough and make it easier to cough up mucus. Your doctor may recommend medicines such as:

  • Prescription cough suppressants, also called antitussives. These medicines can help relieve a cough. However, they're usually used when nothing else works. No evidence shows that over-the-counter cough suppressants relieve a cough.
  • Expectorants. These medicines may loosen mucus, making it easier to cough up.
  • Bronchodilators. These medicines relax your airways.

Other treatments also may relieve an irritated throat and loosen mucus. Examples include using a cool-mist humidifier or steam vaporizer and drinking enough fluids. Examples of fluids are water, soup, and juice. Ask your doctor how much fluid you need.

Cough in Children

No evidence shows that cough and cold medicines help children recover more quickly from colds. These medicines can even harm children. Talk with your child's doctor about your child's cough and how to treat it.


Reference: National Heart Lung and Blood Institute

Last updated April 27, 2017

This information is for general educational uses only. It may not apply to you and your personal medical needs. This information should not be used in place of a visit, call, consultation with or the advice of your physician or health care professional.

Communicate promptly with your physician or other health care professional with any health-related questions or concerns.

Be sure to follow specific instructions given to you by your physician or health care professional.

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