Differential Diagnosis for Chronic Cough

Given the patient's presentation of chronic cough without GERD or heart failure and zero eosinophils, the following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Chronic Bronchitis: This condition is a common cause of chronic cough, especially in smokers or those exposed to pollutants. The absence of eosinophils suggests a non-allergic, non-asthmatic condition, making chronic bronchitis a plausible diagnosis due to its association with chronic inflammation of the bronchial tubes.

• Other Likely Diagnoses

  • Bronchiectasis: A condition characterized by damaged, widened airways, leading to chronic cough and sputum production. It could be considered given the chronic nature of the cough, although imaging would be necessary for diagnosis.
  • Pulmonary Fibrosis: Idiopathic pulmonary fibrosis or other forms could present with chronic cough as a primary symptom. The absence of eosinophils does not rule out this condition, which involves scarring of lung tissue.
  • Chronic Obstructive Pulmonary Disease (COPD): While COPD encompasses chronic bronchitis and emphysema, it is listed separately here as it is a broader category. The chronic cough could be a symptom of COPD, especially in the context of smoking or exposure to harmful substances.

• Do Not Miss Diagnoses

  • Lung Cancer: Although less likely, lung cancer can present with chronic cough and must be considered, especially in smokers or those with a significant exposure history to carcinogens. Early detection is crucial for treatment outcomes.
  • Tuberculosis (TB): Chronic cough is a key symptom of TB. Although less common in some regions, TB is a critical diagnosis not to miss due to its infectious nature and the availability of effective treatment.
  • Sarcoidosis: This condition can cause cough among other symptoms and, while less common, is important to diagnose due to its potential for significant morbidity if left untreated.

• Rare Diagnoses

  • Cystic Fibrosis: Typically diagnosed in childhood, but mild forms can present later in life with chronic cough among other symptoms.
  • Primary Ciliary Dyskinesia: A rare genetic disorder that affects the motor cilia, leading to chronic respiratory infections and cough.
  • Histiocytosis X (Langerhans Cell Histiocytosis): A rare disorder that can cause pulmonary symptoms, including chronic cough, due to the accumulation of Langerhans cells in various organs.