Causes of chronic cough without infection
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Common Non-Infectious Causes of Chronic Cough
Chronic cough, defined as a cough lasting more than 8 weeks in adults, is most often caused by non-infectious conditions. The most common causes include upper airway cough syndrome (previously called postnasal drip), asthma (including cough variant asthma), nonasthmatic eosinophilic bronchitis, and gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux. These conditions account for the majority of chronic cough cases in both Western and Asian populations, with studies showing that these four causes can explain up to 87% of cases in some regions 1345+1 MORE.
Environmental and Lifestyle Triggers
Exposure to cigarette smoke, environmental pollution, and particulates are significant contributors to chronic cough. Both active smoking and passive exposure can lead to persistent cough even in the absence of infection. Environmental irritants and occupational exposures should also be considered as potential causes 135.
Eosinophilic Bronchitis and Atopic Cough
Eosinophilic bronchitis is a notable cause of chronic cough, presenting with sputum eosinophilia but without the airway obstruction seen in asthma. This condition responds well to inhaled corticosteroids. Atopic cough, which is related to allergic tendencies, is also recognized as a common non-infectious cause, especially in some populations 247.
Other Respiratory and Systemic Conditions
Other diseases that can cause chronic cough without infection include chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, bronchiectasis, interstitial lung disease, and obstructive sleep apnea syndrome. Rare causes, such as protracted bacterial bronchitis (when not actively infectious), somatic cough syndrome (psychogenic cough), diffuse panbronchiolitis, and even heart failure, have also been identified. These rare causes collectively account for a small percentage of cases but should be considered when common causes are excluded 15710.
Medication and Drug-Induced Cough
Use of certain medications, particularly angiotensin-converting enzyme (ACE) inhibitors, is a well-known non-infectious cause of chronic cough. Drug-induced lung injury from other medications can also present as chronic cough 357.
Idiopathic and Unexplained Chronic Cough
In some patients, no clear cause is found despite thorough evaluation. This is termed idiopathic or unexplained chronic cough. It is thought that heightened sensitivity of the cough reflex, possibly due to changes in nerve pathways or airway inflammation, may play a role in these cases .
Diagnostic Approach
A detailed history and clinical evaluation are essential to identify the underlying cause. Chest radiography and spirometry are recommended as initial tests. Further investigations, such as high-resolution CT, bronchoscopy, or nasendoscopy, may be needed for rare or refractory cases. Treatment is directed at the underlying cause, and in cases where no cause is found, therapies aimed at reducing cough reflex sensitivity may be considered 35710.
Conclusion
Chronic cough without infection is most commonly due to upper airway cough syndrome, asthma, eosinophilic bronchitis, and GERD, with environmental exposures and certain medications also playing significant roles. Less common causes include a range of respiratory and systemic diseases. A systematic approach to diagnosis and management is crucial for effective treatment and improved patient outcomes.
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Most relevant research papers on this topic
Prevalence, pathogenesis, and causes of chronic cough.
Chronic cough, lasting more than 8 weeks, is common and caused by factors such as cigarette smoking, environmental pollution, and diseases like asthma, eosinophilic bronchitis, and bronchiectasis.
Chronic Cough: Evaluation and Management.
Chronic cough in adults is often caused by upper airway conditions, gastroesophageal reflux, asthma, and nonasthmatic eosinophilic bronchitis.
Chronic Cough: Evaluation and Management.
Chronic cough in adults is often caused by upper airway issues, asthma, and eosinophilic bronchitis, and can be managed with cost-effective diagnostic tests and targeted treatments.
[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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