Chronic Bronchitis: This is often the most common cause of a continuous cough, especially in smokers or those exposed to pollutants. The chronic inflammation of the bronchial tubes leads to a persistent cough.

Asthma: A condition characterized by episodic airway constriction, which can cause a chronic cough, especially at night or with exertion.
Gastroesophageal Reflux Disease (GERD): Stomach acid reflux can irritate the throat, leading to a persistent cough.
Allergic Rhinitis: Postnasal drip from allergies can cause a continuous cough.
Upper Respiratory Tract Infections: Viral or bacterial infections like the common cold or sinusitis can lead to a prolonged cough.

Lung Cancer: Although less common, lung cancer can present with a persistent cough, making it crucial not to miss this diagnosis, especially in smokers or those with a family history.
Tuberculosis (TB): A bacterial infection that can cause a chronic cough, often accompanied by other symptoms like weight loss and night sweats.
Pneumonia: Bacterial or viral pneumonia can cause a severe, persistent cough.
Pulmonary Embolism: A blood clot in the lungs can cause a sudden onset of cough, among other symptoms like chest pain and shortness of breath.

Cystic Fibrosis: A genetic disorder that leads to the production of thick mucus, causing chronic respiratory infections and cough.
Sarcoidosis: An inflammatory disease that can affect the lungs, leading to a persistent cough among other symptoms.
Bronchiectasis: A condition where the airways are permanently enlarged, leading to chronic infections and cough.
Interstitial Lung Disease: A group of disorders that cause scarring of the lung tissue, leading to symptoms including a persistent cough.