Coughing from time to time helps clear particles and secretions from the lungs and helps to prevent infection. However, sometimes a cough can become a chronic condition. A chronic cough is usually defined as a cough that lasts for eight weeks or longer.
Although coughing is not usually a sign of a serious problem, it can be annoying. Coughing frequently is embarrassing, can make you physically tired, make it hard to sleep, and cause you to be dizzy, hoarse, strain muscles, sweat, and leak urine (especially in women).
This article discusses the possible causes and treatments of chronic cough in adults. Coughing that began less than eight weeks ago is discussed separately. (See "Patient information: Acute bronchitis in adults (Beyond the Basics)".) More detailed information about chronic cough is available by subscription. (See "Evaluation of subacute and chronic cough in adults" and "Treatment of subacute and chronic cough in adults".)
CAUSES OF CHRONIC COUGH
The most common causes of chronic cough are postnasal drip, asthma, and acid reflux from the stomach. These three causes are responsible for up to 90 percent of all cases of chronic cough. Less common causes include infections, medications, and lung diseases.
Postnasal drip — Postnasal drip occurs when secretions from the nose drip or flow into the back of the throat from the nose. These secretions can irritate the throat and trigger a cough. Postnasal drip can develop in people with allergies, colds, rhinitis, and sinusitis.
Signs of postnasal drip include a stuffy or runny nose, a sensation of liquid in the back of the throat, and a feeling you need to clear your throat frequently. However, some people have so-called "silent" postnasal drip, which causes no symptoms other than a cough.
Asthma — Asthma is the second most frequent cause of chronic cough in adults, and is the leading cause in children. In addition to coughing, you may also wheeze or feel short of breath. However, some people have a condition known as cough variant asthma, in which cough is the only symptom of asthma. (See "Patient information: Asthma treatment in adolescents and adults (Beyond the Basics)".)
Asthma-related cough may be seasonal, may follow an upper respiratory infection, or may get worse with exposure to cold, dry air, or certain fumes or fragrances.
Acid reflux — Gastroesophageal reflux, also known as acid reflux, occurs when acid from the stomach flows back (refluxes) into the esophagus, the tube connecting the stomach and the throat. Gastroesophageal reflux disease (GERD) refers to symptoms caused by acid reflux. Many people with cough due to acid reflux have heartburn or a sour taste in the mouth. However, some patients with GERD have cough as their only symptom. (See "Patient information: Acid reflux (gastroesophageal reflux disease) in adults (Beyond the Basics)".)
Other causes — A number of other conditions can lead to chronic cough. These include:
Respiratory tract infection — An upper respiratory infection such as a cold can cause a cough that lasts more than eight weeks. This may be due to postnasal drip (as described above), or to irritability in the airways that developed as a result of the infection. Many people with a chronic cough after a respiratory infection respond to treatment for postnasal drip or cough variant asthma. (See 'Postnasal drip' above.)
Sometimes bacterial tracheobronchitis or bacterial sinusitis can develop following a viral upper respiratory tract infection. In almost all cases of bacterial tracheobronchitis, patients will have a cough that produces sputum. The sputum is colored from light yellow to dark green or even brown. Likewise, in almost all cases of cough from bacterial sinusitis, patients will have sinus congestion and the nasal secretions that drip or flow into the back of the throat are similarly off-colored. If such colored sputum or postnasal drip continues unimproved for more than 10 to 14 days, antibiotics may be needed to treat the infection. (See "Patient information: Acute bronchitis in adults (Beyond the Basics)" and "Patient information: Acute sinusitis (sinus infection) (Beyond the Basics)".)
Use of ACE inhibitors — Medications known as angiotensin converting enzyme (ACE) inhibitors, which are commonly used to treat high blood pressure, cause a chronic cough in up to 20 percent of patients. The cough is usually dry and hacking. Switching to another medication often improves the cough over the course of one to two weeks.
Chronic bronchitis — Chronic bronchitis is a condition in which the airways are irritated, causing you to cough, sometimes raising phlegm. Most people with chronic bronchitis are current or past smokers. (See "Patient information: Chronic obstructive pulmonary disease (COPD), including emphysema (Beyond the Basics)".)
Lung cancer — Although lung cancer can cause coughing, very few people with a chronic cough have lung cancer. Cancer is possible, however, especially if you are a smoker and your cough changes suddenly, you begin to cough up blood, or if you continue to cough more than one month after quitting smoking. (See "Patient information: Lung cancer risks, symptoms, and diagnosis (Beyond the Basics)".)
Eosinophilic bronchitis — A special type of inflammation in the airways called eosinophilic bronchitis can cause a chronic cough. This is diagnosed when your breathing tests show no evidence of asthma, but your phlegm or airway biopsy shows cells called eosinophils. Eosinophilic bronchitis is much less common than asthma.
CHRONIC COUGH DIAGNOSIS
To investigate the cause of a chronic cough, your healthcare provider will ask about your symptoms and perform a physical examination.
Based upon your symptoms and examination, your clinician may recommend a trial of treatment before other testing is performed. If you improve with treatment, no further testing is generally needed. If you do NOT improve, or if your diagnosis is not clear, further testing may be recommended, such as:
Lung imaging — If you are a current or former cigarette smoker, or if you have other medical conditions that can affect the lung, a chest X-ray or even a chest CT scan may be done.
Lung function tests — If asthma is suspected but cannot be confirmed, the clinician may perform lung function tests that measure the pattern of air flow into and out of the lungs.
Acid reflux testing — To confirm a diagnosis of acid reflux, a test may be done to measure the acid level of fluid in the esophagus. This test is called a pH probe. In some people, a test called upper endoscopy will be done to look for irritation of the esophagus and to obtain a biopsy of the esophagus. (See "Patient information: Upper endoscopy (Beyond the Basics)" and "Patient information: Acid reflux (gastroesophageal reflux disease) in adults (Beyond the Basics)".)
CHRONIC COUGH TREATMENT
Treatment of chronic cough aims to eliminate the underlying cause. Most of the time, each type of treatment is tried separately, one after another, instead of all at the same time. Seeing which one works best helps to figure out the underlying cause. Here are some examples of treatment choices for different causes of cough.
Postnasal drip — A cough related to postnasal drip may improve with the use of a decongestant, nasal or oral antihistamine, nasal glucocorticoid, or a nasal spray that contains ipratropium. The best treatment (or combination of treatments) depends upon your symptoms and medical history. The following are some examples of how these medications may be used:
If you have postnasal drip from a cold — Antihistamines that are taken as a pill, such as chlorpheniramine (brand name: Chlor-Trimeton®) or clemastine (Tavist®, Dayhist®), may help, but can cause side effects such as drowsiness and drying of the eyes, nose, and mouth. Most of these are available over the counter. Decongestants such as pseudoephedrine can improve nasal congestion, make it easier to blow one’s nose, and thus lessen post nasal drip. Most drugstores in the United States carry pseudoephedrine behind the counter, so you must request it from the pharmacist (a prescription is not required). The nasal spray ipratropium bromide (Atrovent®, available without a prescription) can also help relieve runny nose, postnasal drip, and sneezing associated with a cold.
If you have postnasal drip from allergies (“hay fever”) — Nasal glucocorticoids such as fluticasone (Flonase®), triamcinolone (Nasacort®), or mometasone (Nasonex®) can be prescribed to help reduce nasal inflammation, postnasal drip, and cough. The usual dose is one squirt in each nostril twice per day.
Oral antihistamines such as loratadine (Claritin®), fexofenadine (Allegra®), or cetirizine (Zyrtec®), are also effective for allergic postnasal drip and they are available without a prescription. They are less likely to cause sleepiness than older generation antihistamines such as chlorpheniramine or diphenhydramine. Nasal antihistamine sprays such as azelastine (Astelin®) can also relieve postnasal drip.
All three of these forms of treatment (nasal glucocorticoids, oral antihistamines, and nasal antihistamines) can be tried alone, or they can be used in combination if needed.
Cough variant asthma — If your cough is due to asthma, you will be given the standard treatment for asthma, which includes an inhaled glucocorticoid such as fluticasone (Flovent®), budesonide (Pulmicort®), or beclomethasone (QVAR®). You may also be prescribed an inhaled bronchodilator such as albuterol (ProAir®, Ventolin®, or Proventil®) if you have wheezing or shortness of breath. The glucocorticoid decreases inflammation of the airways while the inhaled bronchodilator opens up the airways. (See "Patient information: Asthma treatment in adolescents and adults (Beyond the Basics)".)
Acid reflux — Cough due to acid reflux may respond to the following lifestyle changes:
- Avoid substances that increase reflux, such as high fat foods, chocolate, colas, red wine, acidic juices, and excessive alcohol
- Avoid eating for two to three hours before lying down
- Elevate the head of the bed six to eight inches
- Lose weight, if you are overweight
- Stop smoking
In addition, you may be given a medication to slow the production of acid in your stomach, called a proton pump inhibitor. Examples of proton pump inhibitors include omeprazole (Prilosec®), esomeprazole (Nexium®), and lansoprazole (Prevacid®). It may take eight or more weeks of treatment before your cough improves. If your cough does not improve during this time, further testing may be recommended.
For more information about acid reflux, (see "Patient information: Acid reflux (gastroesophageal reflux disease) in adults (Beyond the Basics)").
Eosinophilic bronchitis — Eosinophilic bronchitis is treated with inhaled glucocorticoids. These medications are also used for asthma and work to decrease inflammation in the airways. Examples include budesonide (Pulmicort®) and fluticasone (Flovent®).
Cough suppression — If, after a thorough evaluation, the cause of your cough cannot be determined and the cough persists, a medication that suppresses your cough may be recommended.
- Non-prescription cough medicines that contain dextromethorphan (Delsym®) may help suppress the cough reflex.
- Benzonatate (Tessalon®) is a prescription medication that may be recommended if dextromethorphan is not helpful.
- Codeine and hydrocodone are prescription narcotic medications that can be added to cough syrup; these may be tried if other treatments have not been effective. However, both medications can cause you to feel sleepy and should not be used while working or driving.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Lung cancer (The Basics)
Patient information: Acute bronchitis (The Basics)
Patient information: Coughing up blood (The Basics)
Patient information: Cough in adults (The Basics)
Patient information: Idiopathic pulmonary fibrosis (The Basics)
Patient information: Breathing tests (The Basics)
Patient information: Bronchiectasis in adults (The Basics)
Patient information: Interstitial lung disease (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Acute bronchitis in adults (Beyond the Basics)
Patient information: Asthma treatment in adolescents and adults (Beyond the Basics)
Patient information: Acid reflux (gastroesophageal reflux disease) in adults (Beyond the Basics)
Patient information: Chronic obstructive pulmonary disease (COPD), including emphysema (Beyond the Basics)
Patient information: Lung cancer risks, symptoms, and diagnosis (Beyond the Basics)
Patient information: Upper endoscopy (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Clinical manifestations and diagnosis of bronchiectasis in adults
Diagnosis of asthma in adolescents and adults
Evaluation of wheezing illnesses other than asthma in adults
Evaluation of subacute and chronic cough in adults
Hoarseness in adults
The common cold in adults: Treatment and prevention
Treatment of subacute and chronic cough in adults
The following organizations also provide reliable health information.
- American College of Chest Physicians
- Canadian Lung Association