When Coughs Won’t Quit

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Q:Can a cough originate from a problem somewhere other than the lungs? I am being treated for a cough that won’t go away. It has lasted since November 2006. Two rounds of chest X-rays have come back clear. The doctor prescribed antibiotics three different times—prednisone, Musinex (which loosens phlegm), and cough syrup with codeine—but the cough persists. Please help.

A: Your hunch is right. Coughs are symptoms that may be caused by other factors (post-nasal drip, medication, etc.) besides the lungs. Given that yours has persisted for so many months, it is extremely important to find the source: It may be masking another condition (heart, sinus, gastro-esophageal reflux) that is impacting the quality of your life. Fortunately, the underlying cause can often be found and successfully treated.

Coughing is one of the most common reasons why Americans visit their health care providers. While occasional coughing helps the lungs clear out particles or other substances that can lead to infection, persistent coughing can lead to side effects such as painful spasms, fatigue, hoarseness, or even urine leakage. Needless to say, this problem can be embarrassing as well as life-altering.

In order to find the reason for a cough, we often ask whether it just began (acute) or has been going on for eight or more weeks (chronic in adults). We then want to know whether it is productive or non-productive, infectious (pneumonia, whooping cough, influenza, others) or non-infectious (asthma or a cough triggered by gastro-esophageal reflux disease or GERD, heart disease, others).

If your cough is productive, you will cough up phlegm. This is basically mucus being expelled out of the lungs and through your mouth. Sometimes this mucus is clear or has a slight tinge of color. In many cases this type of cough is caused by a virus or, less commonly, a bacterial infection. At other times the phlegm will be a dark yellow, green, gray (especially in smokers), or even have a blood-tinged color. This is even more concerning, especially if you have a fever. This could mean you have a serious bacterial infection, and it would be best to see your health care provider.

If you have a non-productive or dry cough, it may seem like you have something to cough up, but nothing comes out. Common reasons for these coughs include viruses, asthma, emphysema, congestive heart failure, or even something much worse—lung cancer.

Most of our coughs are triggered by one of the following conditions:

Asthma: Many people have asthma and don't know it. This is important because it can be the main source of a cough. Treatment with cough suppressants is not only ineffective, but can be potentially dangerous because the condition can worsen. Other medical approaches (inhalers, oral medications) are needed.

Post-nasal drip: Post-nasal drip syndrome can lead to extra mucus dripping down from the sinuses into the throat, which then tickle the cough sensors in the tubes leading into our lungs. Some people have a silent drip and aren’t even aware it is occurring. But silent or not, the result can be a real annoying outburst of uncontrollable coughing.

Gastroesophageal reflux disease: You may ask, how acid reflux can cause a cough? Well, the reason is that stomach acid can “backwash" up into our esophagus, where there are nerve endings that can trigger a cough. Sometimes a cough caused by GERD is a difficult diagnosis to make because, in many cases, a persistent cough may be the only symptom.

Viruses: Did you ever have a cough that wouldn't give up, especially after you had a cold or the flu? The reason for the persistence of the cough is often due to inflammation that was caused by the virus. This inflammation keeps on irritating the nerve receptors in your bronchial tubes, triggering this dry, hacking cough.

Chronic bronchitis: Often bronchitis is often triggered by tobacco smoking. In this case, the coughing helps to clear the lungs of extra mucus. However, too much coughing is not good and the cause of the cough needs to be addressed; otherwise, significant lung damage may occur. In this case, the cure is to stop smoking.

While not as common, there are additional reasons for a cough. These include but aren’t limited to:

Medications including angiotensin converting enzyme inhibitors (Used for high blood pressure, heart and kidney disease, in a small percentage of people they have the potential to trigger a persistent cough.)
Connective tissue disorder, such as systemic lupus erythematosus
Thyroid disorders that may cause pressure on your trachea and possibly lead to a cough
Heart disease
Infections of the lungs (whooping cough, tuberculosis, others)
Occupational exposure to dust and chemicals
Foreign bodies (nuts, seeds, etc.) that people may remember as something “going down the wrong pipe” while they were eating.
Psychological habit due to anxiety or stress

In general, it is best to see a physician for a cough if:

You’re coughing up blood
Your cough doesn’t improve, even when your other symptoms do
You also have a fever
Your treatment is not working after three or four days
You are short of breath or have chest pain
It interferes with your daily living, including your sleep
The cough lasts more than three weeks
It causes you to pass out

The main reasons for cough are very different, and the specific cause must be determined so it can be properly treated. Pulmonary function testing, a computerized tomography scan or other tests may be needed. Please consider seeking a second opinion from a family physician, general internist, allergist or pulmonary (lung) specialist.

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Robert Danoff, D.O., M.S., is a family physician and program director of The Family Practice Residency, as well as the combined Family Practice/Emergency Medicine Residency programs at Frankford Hospitals, Jefferson Health System, Philadelphia, Pa. He is the medical correspondent for CN8, The Comcast Network, a regular contributor to Discovery Health Online and a contributing writer to The New York Times Special Features. (Read his full bio.)