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Common and Uncommon Causes of a Chronic Cough

Medical Conditions that Cause Persistent Coughing

By

Updated September 06, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What are some common, as well as less common causes of a chronic cough? Living with a chronic cough can be exhausting, as well as worrisome as you wonder what the reason behind your cough may be. Possible causes are listed below, but first, what is a chronic cough?

What is a Chronic Cough

A chronic cough is defined as a cough that lasts for at least 8 weeks. If a cough lasts less than 8 weeks it is considered an acute cough, for example, the type of cough that you may have with the common cold.

The following link discusses the symptom of chronic cough, when you should see your doctor, and how your cough may be evaluated:

Most Common Causes of a Persistent Cough

The 3 most common causes of a chronic cough are:

  • Postnasal drip - Inflammation of the nasal passages (postnasal drip) from rhinosinusitis or sinusitis is the most common cause.

  • Asthma - Asthma is the second most common cause. While some people experience other symptoms such as wheezing and tightness in their chest, other people may have a cough as their only symptom (cough variant asthma.)

  • Gastroesophageal reflux (GERD) - Less well known is that the 3rd most common cause of a persistent cough is acid reflux (GERD.) People may experience heartburn and an acid taste in their mouth, or a cough may be the only symptom. A cough due to GERD is usually worst at night after lying down.

Other Causes Broken Down By Mechanisms

The following list isn't exhaustive, but lists many possible causes. These causes are not listed by how often they may be a cause of a chronic cough.

Infections

  • Viral Infections - Infections such as the common cold and the flu can cause a cough. Although symptoms usually last only a few days, the cough may sometimes persist for several weeks (post-infectious cough.)

  • Bronchitis - While acute bronchitis usually lasts 3 weeks or less, chronic bronchitis is a very common cause of an unrelenting cough. Chronic bronchitis is most common in people who smoke, but other environmental toxins combined with infection or a genetic predisposition may also lead to this condition.

  • Whooping cough (pertussis) - Whooping cough is best known for the whooping sound of a deep inspiration which follows an episode of relentless coughing. While thought of as a disease of the past due to immunizations, and one that occurs in children, whooping cough occurs more often in adults and has increased in recent years in the United States.

  • Tuberculosis - While a third of the population worldwide is felt to be infected with the bacterium that causes tuberculosis, it is fairly uncommon in the United States. People who are more at risk include immigrants and those who have spent a significant amount of time traveling abroad.

  • Fungal Infections - Fungal infections such as aspergillosis, histoplasmosis, and cryptococcosis can cause a cough that persists.

  • Pneumonia - Pneumonia usually causes an acute cough, but sometimes a cough can linger far after treatment is completed.

Tumors

  • Lung cancer - Lung cancer is an important cause of a prolonged cough, with at least half of people newly diagnosed noting this symptom. Many people with lung cancer have experienced a delay in their diagnosis as the cough is attributed to something else.

  • Metastatic tumors - Cancers from other regions of the body that have spread to the lungs (metastatic cancer to the lungs) may cause a continual cough. Tumors that commonly spread to the lungs include breast cancer, colon cancer, prostate cancer, and bladder cancer.

  • Benign lung tumors - Noncancerous lung tumors such as harmartomas can cause a lasting cough.

  • Other cancers - Other tumors in the chest, such as and carcinoid tumors may produce a cough.

Medications

  • Ace inhibitors - Ace inhibitors are medications that are often used to treat heart conditions such as high blood pressure and heart failure. Examples of Ace inhibitors include Capoten (captopril), Vasotec (enalopril) and Zestril (lisinopril)

Inflammation

  • Eosinophilic bronchitis - Eosinophilic bronchitis had recently been found to be a common cause of a lingering cough, accounting for at least 10% of chronic coughs. The only way to diagnose this condition is by looking at a sample of phlegm.

  • Rhinitis - Allergic rhinitis (hayfever) and non-allergic rhinitis (vasomotor rhinitis) can cause a cough that perseveres.

Lung diseases

  • Saroidosis - Sarcoidosis is a rare disease in which granulomas form throughout the body, including the lungs. It usually causes a dry cough.

  • Bronchiectasis - Bronchiectasis is a condition involving narrowing and thickening of the airways, often due to childhood infections.

  • Emphysema - Emphysema is a condition that results in destruction of the alveoli (the smallest of airways,) and is most often caused by smoking.

Irritants

  • Smoker's cough - A smoker's cough is a very common cause of a persistent cough. Early on this cough is usually dry, but after a number of years of smoking, a smoker's cough is often productive of white to yellow phlegm. The cough is often worst in the morning after a awakening, and improves as the day goes on.

  • Occupational or household exposures - Exposures such as wood smoke from a wood burning stove, cooking fumes, dust, and occupational chemicals.

  • Air pollution - Air pollution can at times cause a prolonged cough, especially when it is combined with smoking, environmental allergies, or other lung conditions.

Habit

  • Psychogenic cough - A psychogenic cough is essentially a cough that has become a habit.

Cardiac conditions

  • Heart Failure - Heart failure can cause a prolonged cough and is often accompanied by coughing up frothy pink tinged sputum.

Aspiration

  • Foreign body aspiration - Choking often causes a cough of sudden onset if the item that is breathed in is large. Smaller objects may cause a lingering cough.

Final Thoughts

It's important to see your doctor if you have a cough that persists - even if you think there is a plausible reason. Causes may be mostly a nuisance, for example the postnasal drip from an allergy, or serious, such as lung cancer. Although the serious causes are less common, it can make a difference if they are diagnosed earlier rather than later. For example, lung cancer is most treatable in the early stages of the disease. It's important to keep in mind as well that a chronic cough may be due to more than one cause. For example, someone may have a cough related to both allergies and a condition such as emphysema.

Sources:

Braman, S. Postinfectious cough: ACCP evidence-based clinical practice guidelines. Chest. 2006. 129(1 Suppl):138S-146S.

Brightling, C. Chronic cough due to nonasthmatic eosinophilic bronchitis: ACCP evidence-based clinical practice guidelines. Chest. 2006. 129(1 Suppl):116S-121S.

Dicpinigaitis, P. Angiotensin-Converting Enzyme Inhibitor-Induced Cough. ACCP Evidence-Based Clinical Practice Guidelines. Chest. 2006. 129(1 Suppl):169S-173S.

Kvale, P. Chronic cough due to lung tumors: ACCP evidence-based clinical practice guidelines. Chest. 2006. 129(1 Suppl):147S-153S.

Pratter, M. Overview of Common Causes of Chronic Cough. ACCP Evidence-Based Clinical Practice Guidelines. Chest. 2006. 129(1 Suppl):59S-62S.

Rosen, M. Chronic Cough Due to Tuberculosis and Other Infections. ACCP Evidence-Based Clinical Practice Guidelines. Chest. 2006. 129(1 Suppl):197S-201S.

Udaya, B. and M. Prakash. Uncommon Causes of Cough. ACCP Evidence-Based Clinical Practice Guidelines. Chest. 129(1 Suppl):206S-219S

Young, E. and J. Smith. Quality of life in patients with chronic cough. Therapeutic Advances in Respiratory Disease. 2010. 4(1):49-55.

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