A cough is an annoying symptom that can have many causes.  While cough is sometimes just a minor annoyance, it can warn of a more serious problem. While it can be difficult to identify the trigger of cough, the most common causes of long term cough problems include postnasal drip, asthma and acid reflux . A problematic cough typically disappears once the underlying problem is treated.

Acute cough symptoms
Acute cough lasts for 3 weeks or less; its most frequent cause is the common cold, but occasionally, acute cough can be due to a more serious illness such as pneumonia or congestive heart failure.

Chronic cough symptoms
Chronic cough is more than just an annoyance. By definition, a chronic cough lasts for 3 weeks or longer. In addition to being physically draining, a chronic cough can ruin your sleep, divide you from friends, family or co-workers and leave you feeling angry and frustrated.  A chronic cough can occur with other signs and symptoms, which may include:

• Coughing blood
• Heartburn
• Runny nose
• A sensation of liquid running down the back of your throat
• Shortness of breath
• Sour taste in the mouth
• Stuffy nose
• Wheezing

Complications of chronic cough
During a case of ineffective cough, weakness or paralysis of expiratory muscles can makes it difficult or impossible to "push" air from the lungs.  If you are experiencing this type of trouble coughing, mucus that is abnormally thick and sticky can be difficult to remove from airways by coughing.  As a result, bronchial tubes become abnormally narrowed and obstructed.  Furthermore, a persistent cough can be exhausting. The physical action of coughing can deplete your energy reserves and disrupt your sleep, for example. A chronic cough can also cause:

• Dizziness
• Excessive sweating
• Fractured ribs
• Headache
• Urinary incontinence

When to see a doctor
Any persistent cough can disrupt your life. See your doctor if you have a cough that lingers, especially one that brings up sputum or blood, disturbs your sleep, or affects your work or relationships.  Only a small percentage of people who experience chronic cough are diagnosed lung cancer, and most are current or former smokers. If you smoke now, smoked at one time or your sputum contains blood, see your doctor.

You can also ask yourself the following questions to help you decide whether or not you should see your doctor about problem cough.  Are you:

• Coughing up blood?
• Coughing up thick yellow or green phlegm?
• Losing weight without trying?
• Running a temperature higher than 101°F?
• Sweating excessively at night? (soaking the sheets)
• Wheezing (making a whistling sound when you breathe in)?

Once you decide to see a doctor, learn which tests and procedures you can expect. Read more about how doctors diagnose whooping cough, smokers cough, croup cough and dry cough in our Diagnosing Cough section that follows.