What Causes a Chronic Cough?

Eight reasons—and their treatment

That nagging cough just won't go away. You've had it so long you don't even notice it at times, but it drives your co-workers, friends, and spouse crazy. Is it just an annoying habit or a symptom of a more serious problem?

A medical definition of a chronic cough is one that persists for eight weeks or more. If that occurs, see your doctor for a workup.

There are many causes, but here are eight of the more common. (Eight weeks, eight causes. Get it?)

1. Allergic rhinitis: Nasal allergies can result in a runny or stuffy nose, but it's that drip down the back of your throat that triggers the cough.

Treatment: Find what you're allergic to and stay away from it. Okay, that's not so simple sometimes, so an over-the-counter antihistamine might help. You can use the non-drowsy form; however, the Benadryl type might work even better, depending on your tolerance to the drowsy side effect. For allergy assessment and alternative treatment options, see your doctor.

More information: Allergy Treatment: What Medicines to Take for Allergies—and How to Take Them

2. Asthma: Not everyone with asthma knows they have it. Sometimes, the only symptom is a cough.

Treatment: A doctor will listen to your lungs and may order an in-office pulmonary function test. (You just blow really hard into a tube connected to a machine.) A trial of an inhaler might be justified just to see if it relieves your cough. Exercise, allergies, smoke, barometric pressure changes, or infections may trigger the asthma and hence the cough.

More information: Asthma Guide: Causes, Symptoms, Treatment, What It Is

3. Gastroesophageal acid reflux disease (GERD, heartburn): The acidic contents of your stomach can come up, or reflux, into the back to your throat, irritating it. This may occur only when you are lying asleep, so you never know it's happening. However, because of the chronic irritation, you may develop the cough.

Treatment: Sometimes, a doctor can see this irritation in the throat, but the diagnosis is often made on the basis of strong suspicion. People who are overweight or smoke are prone to GERD. Antacids can help, along with avoiding heavy meals and alcohol in the evening. You can try propping up the head of your bed on a book or two. Your doctor may prescribe a medication to stop stomach acid production altogether. Rarely, people require surgery to fix a dysfunctional stomach valve.

More information: The Most Common Type of Heartburn: Non-Erosive Esophageal Reflux Disease

4. Smoking: Is there anyone who does not know smoking damages your lungs and throat? That includes tobacco cigarettes, cigars, hookah (just another way to smoke tobacco), marijuana, or anything else you decide to suck down your windpipe.

Treatment: Quit. Completely. Now.

More information: American Lung Association: How to Quit Smoking

5. Medications: Never stop taking a prescription medication without talking it over with your prescribing doctor, but know that some can have the side effect of a chronic cough. One well-known culprit group is ACE inhibitors, which are used for heart or blood pressure problems and diabetes. Examples include lisinopril (Prinivil) and enalapril (Vasotec), to name just two of many. They're fantastic and effective medications, but your doctor should be able to find a good substitute if the ACE is causing you to cough.

6. Infections: Any respiratory infection can cause a cough. Some bacterial and fungal infections, even tuberculosis, can cause a chronic cough. You'll at least need a chest X-ray for diagnosis.

7. Lung cancer: More rare than most of the others but the one we all fear. Putting off the diagnosis will only decrease your potential benefit in treatment.

8. Sleep apnea: This is usually not in the list of causes for a chronic cough, but it is in mine, since it was my reason for a cough that persisted over three years without a diagnosis. I slept with my mouth open. The diagnosis was made after a sleep lab study.

Treatment: A continuous positive airway pressure (CPAP) machine

More information: Sleep Apnea Information: A Doctor Answers 5 Frequently Asked Questions and Video: "Experience a Sleep Apnea Lab"

Eight weeks is not a magic number. Don't wait that long if you are having other problems, such as fever, weight loss, fatigue, coughing up blood, or shortness of breath, or if you're just worried.

By James Hubbard, MD, MPH
My Family Doctor Blog

[Originally posted May 18, 2010, James Hubbard’s My Family Doctor Web site.]