A cough is a sudden expulsion of air from the lungs. Its purpose is usually to clear secretions and inhaled foreign substances from the lungs and respiratory tract.
There are different types of cough:
- Acute cough—lasts for less than 3 weeks
- Subacute cough—lasts 3-8 weeks
- Chronic cough—lasts longer than 8 weeks
Subacute cough is often a cough that follows a respiratory infection. It can also be caused by exposure to irritants or to anything that can cause chronic cough.
A chronic cough has many causes. Common examples include:
- Chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis or emphysema
- Acid reflux from the stomach into the esophagus—gastroesophageal reflux disease (GERD)
Postnasal drip, which may be due to:
- Repeated inhalation of environmental irritants
- Sinus inflammation
- Certain medications, such as ACE inhibitors
Factors that may increase your risk of developing a cough include:
- Tobacco smoke
- Harmful fumes
- Allergens, such as pollen and dust
- Smog and other environmental pollutants
A cough can be a symptom of an underlying condition.
Coughs can be productive or dry. You may find that your cough is worse when waking up and during the night while lying down.
When Should I Call My Doctor?
Call your doctor if you have:
- Acute cough that worsens or does not go away on its own
- Cough lasting more than 8 weeks
- Signs of an infection, including fever and chills
- Cough with wheezing
- Blood in the sputum
When Should I Call for Medical Help Immediately?
Call for medical help or go to the emergency room right away if you have cough with:
- Pink or frothy sputum
- Trouble breathing
- Chest pain
- Rapid heartbeat
- Swelling in the legs
You will be asked about your symptoms and medical history. A physical exam will be done.
Acute cough is usually diagnosed by its accompanying symptoms.
Your bodily fluids may be tested. This can be done with:
- Blood tests
- Skin tests
- Analysis of a sputum sample
Images may be taken of your bodily structures. This can be done with:
During a bronchoscopy, a lighted tube with a camera is inserted into the lungs. Tissue samples can also be taken for evaluation under a microscope.
Your lung function and capacity may be tested. This can be done with pulmonary function tests.
The best treatment for a cough is to treat the underlying condition.
There are many over-the-counter (OTC) cough and cold products available. These include decongestants, expectorants, antihistamines, and antitussives.
Note: Cough and cold medications should not be used in children under 2 years old, and they are not recommended in children under 4 years old. The US Food and Drug Administration has not completed its review regarding the safety of over-the-counter cough and cold medications in children ages 2-11 years. Rare, but serious side effects have been reported.
Consider putting a steam vaporizer or cool-mist humidifier in your room. This type of moisture therapy may help to make secretions looser and easier to cough up.
To reduce your chances of developing a cough:
- If you smoke, talk to your doctor about strategies to quit. Smoking affects your lung function and increases your risk of many diseases.
- Get proper treatment for the underlying condition.
When working in areas where harmful fumes or airborne substances are present:
- Be sure the area is properly ventilated.
- Wear a protective mask or respirator.
- Reviewer: David L. Horn, MD, FACP
- Review Date: 08/2017 -
- Update Date: 09/17/2014 -