8 Causes of Chronic Cough—and What to Do About It

Finally, some relief from all the hacking.

Woman coughing
Photo: Getty Images

You've been coughing for weeks—but how do you know if it's just a hard-to-shake cold or something more serious? A chronic cough, defined by the National Institutes of Health as a cough that lasts more than eight weeks, has various possible causes. According to the American Lung Association, common causes include asthma, chronic obstructive pulmonary disease (COPD), and digestive disordered like GERD.

Only your doctor can truly tell for sure what's behind your endless hacking, but here are the most common causes of chronic cough—and what you can do about it.

1. Asthma and allergies

Asthma, a chronic disease that affects the lungs, causes repeated episodes (known as asthma attacks) of wheezing, shortness of breath, chest tightness, and nighttime or early morning coughing, per the Centers for Disease Control and Prevention (CDC). It’s one of the most common diseases that affects kids, but it can affect adults, too.

Asthma triggers are different for everyone, with everything from exercise and certain foods to cigarette smoke and other airborne irritants bringing on an attack. Identifying and avoiding triggers (or at least minimizing exposure to them) is a key part of managing asthma.

But you don’t need to have asthma to be affected by airborne irritants. According to the American College of Allergy, Asthma & Immunology, 40 to 60 million Americans suffer from allergic rhinitis, commonly known as hay fever, which causes coughing along with other symptoms like a stuffy nose and sneezing. Common triggers for hay fever include pollen, dust, and pet dander.

You may be able to determine whether your cough is caused by allergies by keeping track of whether it comes and goes in certain situations. If your coughing magically stops when you step into an air-conditioned room on a dry, pollen-heavy day, or if gets worse every time you come into contact with your friend’s cat, you probably have allergies. If you're not sure what's triggering your allergic cough, your doctor can give you a skin test or blood test to pinpoint the allergy.

2. Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a term that covers two main conditions—emphysema and chronic bronchitis, per the National Institutes of Health. In emphysema, the walls between many of the air sacs are damaged. As a result, the air sacs lose their shape and become floppy. This damage also can destroy the walls of the air sacs, leading to fewer and larger air sacs instead of many tiny ones. If this happens, the amount of gas exchange in the lungs is reduced.

In chronic bronchitis, the lining of the airways stays constantly irritated and inflamed, and this causes the lining to swell. Lots of thick mucus forms in the airways, making it hard to breathe. To be diagnosed with chronic bronchitis, you must have a cough and mucus most days for at least three months a year, for two years in a row, says Johns Hopkins Medicine. Plus, other causes of symptoms, such as tuberculosis or other lung diseases, must be ruled out.

Most people diagnosed with COPD have both emphysema and chronic bronchitis, but the severity of each condition varies from person to person. Thus, the general term COPD is more accurate. As well as coughing, symptoms include wheezing, shortness of breath and tightness in the chest.

According to the National Heart, Lung, and Blood Institute, smoking is the leading cause of COPD, but up to 25 percent of people with COPD have never smoked at all. Other causes of COPD include long-term exposure to air pollution, chemical fumes and other lung irritants.

Your doctor may check you for COPD (particularly if you have risk factors, such as smoking), after ruling out other common causes of cough. To determine if you have COPD, your doctor is likely to conduct some tests, including spirometry, which involves inhaling as deeply as you can and then exhaling into a tube.

3. Gastroesophageal reflux disease

The main symptom of gastroesophageal reflux disease (GERD), a digestive disorder that occurs when stomach acid, food, and fluids back up into the esophagus due to a weak valve, is killer heartburn. But coughing is another common symptom, along with chest pain and wheezing.

According to the American Academy of Allergy, Asthma & Immunology, GERD affects people of all ages, from infants to older adults, and people with asthma are at higher risk of developing the disorder. This is because asthma attacks can cause the lower esophageal sphincter to relax, which lets the contents of the stomach to flow back into the esophagus.

The AAAAI recommends various lifestyle changes to help ease the symptoms of GERD (including that nasty cough), such as elevating the head of the bed by six to eight inches, losing weight, stopping smoking, drinking less alcohol, restricting portion sizes, avoiding heavy evening meals, and cutting down on caffeine.

4. Respiratory tract infection

Coughing is one of the most common symptoms of colds and flu and other respiratory tract infections (infections that interfere with normal breathing). The other symptoms that accompany colds and flu, such as stuffy nose and a fever, are telltale signs that a viral infection is causing your cough, per the US National Library of Medicine.

A cough can outlast all those other symptoms, perhaps because the air passages in your lungs remain sensitive and inflamed. When this occurs, it's called chronic upper airway cough syndrome (or postnasal drip), which creates extra mucus in the back of the nose and throat, and triggers more throat-clearing and coughing than normal.

A more serious respiratory tract infection is pneumonia, which can be caused by bacteria or viruses. A cough, often producing a greenish or rust-colored mucus, is one of the characteristic symptoms of the illness, along with fever, chills, chest pain, weakness, fatigue, and nausea, per the Centers for Disease Control and Prevention. These symptoms may present differently depending on your age; older adults may not experience a fever, for instance, or they may have a cough but no mucus.

Pneumonia is treated with antibiotics and generally clears up within two or three weeks. As with the cold and flu, however, the cough can linger for much longer.

People who have COPD can be more susceptible to such respiratory tract infections, and may experience exacerbations—episodes of potentially life-threatening shortness of breath—when they catch a cold or breath in air pollution or other irritants.

5. Air pollution

Various pollutants and irritants in the air can cause a persistent cough. Even short-term exposure to fumes (such as diesel exhaust) can result in cough, phlegm, and lung irritation. Fumes can also exacerbate the symptoms of allergies or asthma.

Similarly, mold spores found in and around homes can cause wheezing and coughing when inhaled. In the wake of Hurricane Katrina, New Orleans reported a sudden spike in persistent cough complaints among returning residents. This so-called “Katrina cough” was believed to stem from the mold caused by the flooding, as well as by dry weather and the construction dust in the city.

6. ACE inhibitors

Angiotensin converting enzyme (ACE) inhibitors are widely used to treat heart failure and hypertension (high blood pressure) often cause a persistent dry cough. According to a 2012 article in the British Medical Journal, this may be caused by increased concentrations of bradykinin, a substance that breaks down in the body and accumulates in the respiratory tract, leading to irritation.

You should never stop taking prescribed medication without consulting with your doctor, and ACE inhibitors are important medications for lowering blood pressure (a more serious condition than a cough). However, you may be able to switch from ACE inhibitors to angiotensin II receptor blockers (ARBs), which do not inhibit the breakdown of kinins and are less likely to cause troublesome coughing. If you think your chronic cough is linked to a drug you’re taking, check in with your doctor and see if you have other options.

8. Pertussis

Also known as whooping cough, pertussis is a highly contagious respiratory illness caused by the bacterium Bordetella pertussis. Common symptoms include a slight fever, a runny nose, and, most notably, a violent cough that can make breathing difficult. Attempting to inhale air into the lungs between coughs can produce a distinctive, high-pitched whooping sound. After the initial stage, many people do not have a fever, but the cough that accompanies pertussis can persist for several weeks.

The best way to protect against pertussis is by getting vaccinated, says the Centers for Disease Control and Prevention. Although the vaccine isn’t 100 percent effective (no vaccine is), if you get the illness after being vaccinated, it’s usually not as bad.

8. Chronic Smoking

People who smoke often develop a cough, caused by the body’s natural response to get rid of the chemicals that enter the airways and lungs via tobacco use. In this case, a chronic cough is often known as smoker’s cough. It may begin as a dry cough, but can eventually produce phlegm.

A study on young military personnel, published in the journal Annals of Medicine in 2010, found that over 40 percent of daily smokers and 27 percent of occasional smokers experienced chronic cough and phlegm production. Naturally, the easiest way to get rid of smoker’s cough is to quit smoking, and if you need help with that, your doctor can point you in the right direction.

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