Patient information: Chronic cough in adults

OVERVIEW

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 can cause you to be dizzy, hoarse, to strain muscles, to sweat, and to 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".) 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 into the back of the throat. 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".)

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 — Acid reflux (GERD) develops when acid from the stomach flows back (refluxes) into the tube connecting the stomach and the throat (the esophagus). Many people with cough due to acid reflux have heartburn or a sour taste in the mouth. The presence of this acidic material can lead to chronic irritation and coughing. (See "Patient information: Gastroesophageal reflux disease in adults".)

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 sometimes 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. (See "Patient information: Acute bronchitis in adults".)

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)".)

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".)

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. A chest X-ray is generally recommended if your cough has persisted for 8 weeks or more.

Based upon your symptoms and examination, your clinician may recommend a trial of treatment before any further testing is performed. If you improve with treatment, no further testing will be needed. If you do not improve or your diagnosis is not clear, further testing may be recommended before you start treatment.

Lung function tests — If asthma is suspected but cannot be confirmed, the clinician may perform lung function tests. These 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" and "Patient information: Gastroesophageal reflux disease in adults".)

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. As an example, if you have nasal allergies, medications are chosen to control allergy symptoms.

Nasal glucocorticoids — A nasal glucocorticoid such as fluticasone (Flonase®) may help to reduce postnasal drip. The dose is one squirt in each nostril twice per day. Other glucocorticoid nasal sprays may also be effective.

Oral antihistamines — Antihistamines that are taken as a pill, such as chlorpheniramine (Chlor-Trimeton®) clemastine (Tavist®, Dayhist®) may also 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. Antihistamines that are less likely to cause sleepiness, such as loratadine or cetirizine, are less likely to help with cough.

Decongestant — Pseudoephedrine is a decongestant that can improve nasal congestion. Most drugstores in the United States carry pseudoephedrine behind the counter, so you must request it from the pharmacist (a prescription is not required).

Nasal antihistamines — A prescription nasal antihistamine spray, such as azelastine (Astelin®), can relieve symptoms of post-nasal drip, congestion, and sneezing.

Nasal sprays — Nasal sprays, including ipratropium bromide (Atrovent®, available by prescription) can relieve runny nose, postnasal drip, and sneezing.

Cough variant asthma — If your cough is due to asthma, you will be given the standard treatment for asthma, which includes an inhaled bronchodilator and inhaled glucocorticoid. These inhaled medicines act to decrease inflammation (swelling) of the airways. (See "Patient information: Asthma treatment in adolescents and adults".)

Acid reflux — Cough due to acid reflux may respond to the following lifestyle changes:

• Lose weight if you are overweight
• Avoid substances that increase reflux, such as high fat foods, chocolate, colas, red wine, acidic juices, and excessive alcohol
• Stop smoking
• Avoid meals for two to three hours before lying down
• Elevate the head of the bed three to four inches

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: Gastroesophageal reflux disease in adults".

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 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 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. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Acute bronchitis in adults
Patient information: Asthma treatment in adolescents and adults
Patient information: Gastroesophageal reflux disease in adults
Patient information: Chronic obstructive pulmonary disease (COPD)
Patient information: Lung cancer risks, symptoms, and diagnosis
Patient information: Upper endoscopy

Professional Level Information:
Clinical manifestations and diagnosis of bronchiectasis
Diagnosis of asthma in adolescents and adults
Diagnosis 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

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• American College of Chest Physicians

      (www.chestnet.org/patients/guides/cough/index.php)

• Canadian Lung Association

      (www.lung.ca/diseases-maladies/a-z/cough-toux/index_e.php)

• KidsHealth

      (http://kidshealth.org/research/cough_culprits.html)

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