Differential Diagnosis for Cough of 6 Weeks Duration
Single Most Likely Diagnosis
- Chronic Postnasal Drip (Upper Airway Secretion Syndrome): This is often the most common cause of a chronic cough, especially when it persists for more than 6 weeks. It's usually due to allergic rhinitis, non-allergic rhinitis, or sinus infections, leading to a constant drip of mucus into the throat, triggering cough.
Other Likely Diagnoses
- Asthma: Cough can be a sole symptom of asthma, especially in cases of cough-variant asthma. It's characterized by a dry, non-productive cough that can be worse at night or with exercise.
- Gastroesophageal Reflux Disease (GERD): Stomach acid reflux into the esophagus can irritate the throat and lungs, causing a chronic cough. This is more likely if the cough is worse after eating or at night.
- Chronic Bronchitis: Part of chronic obstructive pulmonary disease (COPD), chronic bronchitis involves inflammation of the bronchial tubes, leading to a persistent cough, often with mucus production.
Do Not Miss Diagnoses
- Lung Cancer: Although less common, lung cancer can present with a persistent cough. It's crucial to consider this, especially in smokers or those with a significant smoking history.
- Tuberculosis (TB): A chronic cough can be a symptom of pulmonary TB. It's essential to consider this diagnosis, especially in individuals who have been exposed to TB, have a weakened immune system, or have recently traveled to areas with high TB prevalence.
- Pneumonia: While typically presenting acutely, some forms of pneumonia (like mycoplasma pneumonia) can have a more chronic course, leading to a prolonged cough.
Rare Diagnoses
- Cystic Fibrosis: Although more commonly diagnosed in childhood, cystic fibrosis can sometimes present in adults with a chronic cough, among other symptoms like recurrent lung infections and malabsorption.
- Sarcoidosis: This inflammatory disease can affect multiple parts of the body, including the lungs, leading to symptoms like a chronic cough, shortness of breath, and chest pain.
- Eosinophilic Bronchitis: A condition characterized by an eosinophilic infiltration of the airway walls, leading to a chronic cough without asthma or airway obstruction.