Causes of persistent cough
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Common Causes of Persistent Cough in Adults
Persistent cough, often defined as a cough lasting more than 8 weeks, is most frequently caused by a few key conditions. The most common causes include upper airway cough syndrome (previously known as postnasal drip), asthma (including cough-variant and cough-predominant asthma), gastroesophageal reflux disease (GERD), and nonasthmatic eosinophilic bronchitis Niimi2013Irwin2002Chung2008+2 MORE. Chronic bronchitis, often related to cigarette smoking or exposure to irritants, is also a significant contributor Irwin2002Chung2008Irwin2015. Less common causes include bronchiectasis, pulmonary fibrosis, and the use of angiotensin-converting enzyme (ACE) inhibitors Irwin2002Chung2008Michaudet2017.
Asthma and Asthma Variants as Major Contributors
Asthma, particularly cough-variant asthma (CVA) and cough-predominant asthma (CPA), is a leading cause of persistent cough. Studies have shown that CVA and CPA together account for a significant proportion of chronic cough cases, with CVA being the most common Niimi2013Salinas2020. Eosinophilic bronchitis, a non-asthmatic airway inflammation, is another important cause Irwin2002Chung2008Michaudet2017.
Upper Airway Cough Syndrome and Postnasal Drip
Upper airway cough syndrome, often resulting from postnasal drip due to rhinosinusitis or allergies, is a frequent cause of chronic cough in both adults and children Irwin2002Salinas2020Chung2008+2 MORE. This condition is characterized by the sensation of mucus dripping down the back of the throat, triggering the cough reflex.
Gastroesophageal Reflux Disease (GERD)
GERD is a well-established cause of persistent cough, even in the absence of classic reflux symptoms. Acid reflux can trigger cough through a reflex mechanism or by direct irritation of the airway Irwin2002Chung2008Irwin2015+4 MORE. Studies have shown that GERD is a strong predictor of cough persistence over time .
Other Notable Causes and Risk Factors
Other causes of persistent cough include chronic obstructive pulmonary disease (COPD), environmental exposures (such as pollution or smoke), bronchiectasis, and less commonly, serious conditions like lung cancer, sarcoidosis, or heart failure Irwin2002Chung2008Irwin2015+1 MORE. In rare cases, persistent cough may be idiopathic, meaning no clear cause is found .
Certain risk factors can predict the persistence of cough, such as a family history of chronic cough, sensitivity to cold air, and cough triggered by eating or specific foods . In children, protracted bacterial bronchitis is also a common cause Salinas2020Michaudet2017.
Post-Infectious Persistent Cough
A subset of patients may develop a persistent cough following a respiratory viral infection. This post-infectious cough is thought to result from heightened cough reflex sensitivity, which can persist even after other symptoms have resolved .
Conclusion
Persistent cough is most commonly caused by upper airway cough syndrome, asthma (including its variants), GERD, and chronic bronchitis. Other causes include environmental exposures, certain medications, and less frequently, more serious diseases. Identifying the underlying cause is crucial for effective treatment, and in most cases, a systematic approach can lead to a successful diagnosis and management plan Niimi2013Irwin2002Chung2008+2 MORE.
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Most relevant research papers on this topic
Children with Persistent Cough
An integrated approach is crucial for differential diagnosis and specific treatment of chronic cough in children, with upper airway cough syndrome, cough-variant asthma, and prolonged bacterial bronchitis being common causes.
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[Progress in the pathogenesis of post-infectious persistent cough].
Post-viral persistent cough may result from cough hypersensitivity, a protective strategy to prevent viral spread, but excessive coughing can become a disease.
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