Differential Diagnosis for Chronic Cough

Single Most Likely Diagnosis

• Gastroesophageal Reflux Disease (GERD): This is often considered the most common cause of chronic cough, especially in the absence of other symptoms. GERD can cause stomach acid to flow up into the esophagus, irritating the throat and triggering a cough.

Other Likely Diagnoses

• Asthma: A common condition that can cause chronic cough, often accompanied by wheezing and shortness of breath. Asthma can be allergic or non-allergic and may be triggered by various factors including allergens, exercise, or cold air.
• Chronic Obstructive Pulmonary Disease (COPD): Includes conditions like emphysema and chronic bronchitis, which can cause a chronic cough, often productive of mucus. COPD is typically associated with a history of smoking.
• Postnasal Drip (Upper Airway Secretion Syndrome): This occurs when excess mucus from the nose drips down the back of the throat, triggering a cough. It can be due to allergies, a cold, or sinus infections.
• Medication-Induced Cough: Certain medications, most notably ACE inhibitors used to treat high blood pressure, can cause a chronic cough as a side effect.

Do Not Miss Diagnoses

• Lung Cancer: Although less common, lung cancer can present with a chronic cough, sometimes accompanied by weight loss, chest pain, or coughing up blood. It's crucial to consider this diagnosis, especially in smokers or those with a significant smoking history.
• Tuberculosis (TB): A bacterial infection that can cause a chronic cough, often accompanied by fever, night sweats, and weight loss. TB is more common in certain populations, such as those with compromised immune systems or recent travel to endemic areas.
• Pulmonary Embolism: While typically presenting acutely, in some cases, a pulmonary embolism can cause a chronic cough, especially if it's recurrent or if there's associated pulmonary infarction.

Rare Diagnoses

• Cystic Fibrosis: A genetic disorder that leads to the production of thick, sticky mucus, which can cause chronic cough and recurrent lung infections. It's typically diagnosed in childhood but can be considered in adults with unexplained chronic respiratory symptoms.
• Sarcoidosis: An inflammatory disease that can affect multiple parts of the body, including the lungs, leading to a chronic cough among other symptoms.
• Bronchiectasis: A condition characterized by damage to the airways, leading to chronic cough and recurrent infections. It can be caused by infections, cystic fibrosis, or other conditions.

Each of these diagnoses requires a thorough workup, including a detailed medical history, physical examination, and potentially diagnostic tests such as chest X-rays, spirometry, or CT scans, to determine the underlying cause of the chronic cough and guide appropriate treatment.