Viral Upper Respiratory Tract Infection (URTI): This is the most common cause of nasal congestion and cough, often lasting more than a week. The symptoms are typical for a viral infection, which is usually self-limiting.

Allergic Rhinitis: Prolonged exposure to allergens can cause chronic nasal congestion and cough, especially in individuals with a history of allergies.
Acute Sinusitis: An infection of the sinuses can present with nasal congestion, cough, and facial pain, often following an upper respiratory infection.
Asthma: Cough and wheezing can be symptoms of asthma, especially if triggered by respiratory infections or allergens.
Chronic Obstructive Pulmonary Disease (COPD): In smokers or individuals with a history of lung disease, a chronic cough can be a symptom of COPD.

Pneumonia: Although less common, pneumonia can present with cough and should be considered, especially in vulnerable populations like the elderly, young children, or those with compromised immune systems.
Pertussis (Whooping Cough): A highly contagious bacterial infection that can cause a persistent cough, often with a characteristic whoop sound.
Tuberculosis (TB): A chronic infection that can cause cough, among other symptoms, and is crucial to diagnose due to its public health implications and the need for specific treatment.
Lung Cancer: Though rare, a persistent cough can be an early symptom of lung cancer, particularly in smokers or those with a history of smoking.

Cystic Fibrosis: A genetic disorder that can cause chronic respiratory infections and cough, typically diagnosed in childhood but can be missed until adulthood.
Bronchiectasis: A condition characterized by damaged airways, leading to chronic cough and recurrent infections.
Sarcoidosis: An autoimmune disease that can affect the lungs, causing cough and other respiratory symptoms.
Foreign Body Aspiration: Although more common in children, adults can also accidentally inhale objects, leading to persistent cough and respiratory issues.