Differential Diagnosis for Dry Cough

• Single Most Likely Diagnosis
  • Postnasal drip (upper airway secretion syndrome): This is often the most common cause of dry cough, resulting from the trickle of secretions from the nose or sinuses into the back of the throat, triggering cough.
• Other Likely Diagnoses
  • Asthma: A chronic inflammatory disease of the airways that can cause dry cough, especially at night or with exertion.
  • Gastroesophageal reflux disease (GERD): Stomach acid reflux into the esophagus can irritate the throat and trigger a dry cough.
  • Allergic rhinitis: Similar to postnasal drip, allergies can cause an increase in nasal secretions, leading to a dry cough.
  • Inhaled irritants (e.g., smoke, pollution): Exposure to irritants can directly irritate the airways, causing a dry cough.
• Do Not Miss Diagnoses
  • Pulmonary embolism: Although less common, a pulmonary embolism can present with a sudden onset of dry cough and is a life-threatening condition that requires immediate medical attention.
  • Pneumonia: Certain types of pneumonia, especially those caused by atypical bacteria (like Mycoplasma pneumoniae), can present with a dry cough.
  • Lung cancer: A persistent dry cough can be an early symptom of lung cancer, making it crucial not to miss this diagnosis, especially in smokers or those with a history of smoking.
  • Tuberculosis (TB): TB can cause a chronic dry cough, and although less common in some areas, it's a critical diagnosis not to miss due to its public health implications and the need for specific treatment.
• Rare Diagnoses
  • Sarcoidosis: A condition characterized by the growth of granulomas (inflammatory cells) in various parts of the body, including the lungs, which can cause a dry cough.
  • Eosinophilic pneumonia: A rare condition where eosinophils (a type of white blood cell) accumulate in the lungs, leading to inflammation and potentially a dry cough.
  • Interstitial lung disease: A broad category of diseases that affect the interstitial spaces of the lungs, including conditions like idiopathic pulmonary fibrosis, which can cause a dry cough.
  • Angiotensin-converting enzyme (ACE) inhibitor-induced cough: Certain medications, notably ACE inhibitors used to treat hypertension and heart failure, can cause a dry cough in some patients as a side effect.