Cough causes
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Acute Cough Causes: Common Cold and Respiratory Infections
Acute cough, which lasts less than three weeks, is most often caused by viral respiratory infections such as the common cold. The cough is usually triggered by irritation and inflammation of the upper airway structures due to the viral infection. In many cases, the cough can persist even after other cold symptoms have resolved, sometimes due to ongoing inflammation or heightened sensitivity of the cough reflex. Other causes of acute cough include exacerbations of underlying conditions like asthma or chronic obstructive pulmonary disease (COPD), and pneumonia, but these are less common than viral infections 6810.
Subacute Cough: Postinfectious and Exacerbation of Chronic Diseases
Subacute cough, lasting three to eight weeks, is frequently due to a postinfectious process, where the cough continues after a viral upper respiratory infection. This is often related to an inflammatory response in the airways. Exacerbations of chronic diseases such as asthma, COPD, and upper airway cough syndrome (UACS) are also common causes in this period 86.
Chronic Cough: Major Causes and Pathogenic Triad
Chronic cough, defined as lasting more than eight weeks, is most commonly caused by a few key conditions. The most frequent causes are:
- Upper Airway Cough Syndrome (UACS), previously known as postnasal drip syndrome, often due to rhinosinus conditions.
- Asthma, which can present with cough as the main or only symptom.
- Gastroesophageal Reflux Disease (GERD), where stomach acid irritates the airway.
- Nonasthmatic Eosinophilic Bronchitis (NAEB), which involves airway inflammation without the typical features of asthma.
These four conditions, alone or in combination, account for the vast majority of chronic cough cases. In fact, asthma, UACS, and GERD together are responsible for over 90% of chronic cough cases in adults 1234+2 MORE.
Other Important Causes of Chronic Cough
Other less common but important causes of chronic cough include:
- Chronic bronchitis, often related to cigarette smoking or exposure to irritants.
- Bronchiectasis, a condition involving permanent enlargement of parts of the airways.
- Environmental and occupational exposures, such as inhalation of irritants, allergens, or tobacco smoke.
- Medication side effects, especially from angiotensin-converting enzyme (ACE) inhibitors.
- Chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and immunodeficiency.
- Obstructive sleep apnea and rare conditions like lung cancer, sarcoidosis, heart failure, tuberculosis, and aspiration 3457+1 MORE.
Cough in Children
In children, chronic cough is most often caused by asthma, protracted bacterial bronchitis, and upper airway cough syndrome. The evaluation and management should focus on these common causes first .
Mechanisms and Pathophysiology
Cough is a reflex to clear the airways, but in chronic cases, the cough reflex can become hypersensitive. This heightened sensitivity may persist even after the original cause is gone, due to changes in nerve pathways or ongoing airway inflammation. In some cases, no clear cause is found, leading to a diagnosis of idiopathic cough 310.
Conclusion
Cough is a common symptom with a wide range of causes. Acute cough is usually due to viral infections, while chronic cough is most often caused by upper airway cough syndrome, asthma, GERD, and nonasthmatic eosinophilic bronchitis. Environmental exposures, chronic bronchitis, bronchiectasis, and certain medications are also important contributors. A systematic approach focusing on the most common causes is recommended for effective diagnosis and management.
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