Differential Diagnosis for Persistent Cough Worsening Over One Month

Single Most Likely Diagnosis

• Chronic Bronchitis: This is a common condition characterized by inflammation of the bronchial tubes, often due to smoking or exposure to irritants. A persistent cough that worsens over time is a hallmark symptom, making it the most likely diagnosis for a cough lasting one month.

Other Likely Diagnoses

• Asthma: Asthma can cause a chronic cough, especially if it worsens over time and is accompanied by other symptoms like wheezing or shortness of breath. The cough in asthma can be dry or productive and may vary in severity.
• Gastroesophageal Reflux Disease (GERD): GERD can lead to a chronic cough due to the reflux of stomach acid into the esophagus, irritating the throat and lungs. Symptoms can worsen over time if not treated.
• Postnasal Drip (Upper Airway Secretion Syndrome): This condition involves the dripping of mucus from the back of the nose down into the throat, causing a chronic cough. It can be due to allergies, a cold, or sinus infections.

Do Not Miss Diagnoses

• Lung Cancer: Although less common, lung cancer is a critical diagnosis not to miss. A persistent cough that worsens over time, especially in smokers or those exposed to carcinogens, could be a symptom of lung cancer.
• Tuberculosis (TB): TB is a bacterial infection that can cause a chronic cough, among other symptoms like weight loss, fever, and night sweats. It's crucial to consider TB, especially in individuals who have been exposed or have weakened immune systems.
• Pulmonary Embolism: While less common as a cause of a persistent cough, pulmonary embolism (a blood clot in the lungs) can present with a cough, especially if it's accompanied by shortness of breath, chest pain, or other concerning symptoms.

Rare Diagnoses

• Sarcoidosis: This is a disease characterized by the growth of granulomas (inflammatory cells) in various parts of the body, including the lungs. It can cause a chronic cough, among other symptoms.
• Cystic Fibrosis: Although more commonly diagnosed in childhood, cystic fibrosis can sometimes present in adults with a chronic cough, recurrent lung infections, and other respiratory symptoms.
• Eosinophilic Pneumonia: A rare condition characterized by the infiltration of eosinophils (a type of white blood cell) into the lungs, leading to inflammation and symptoms like a chronic cough.