Persistent dry irritative cough

Specialty: Respiratory.

• persistent dry non-productive cough
• long-standing unproductive cough

Why it occurs

• Treatment with angiotensin-converting enzyme (ACE) inhibitors (the local accumulation of bradykinins and substance P in the airways directly stimulates nociceptive C fibers, causing persistent non-productive dry cough)
• Cough-variant asthma (cough-variant asthma, where bronchial inflammation manifests only with a dry cough when faced with physical or environmental triggers)
• Gastroesophageal reflux disease (GERD) with microaspiration or stimulation of the esophagobronchial vagal reflex
• Non-asthmatic eosinophilic bronchitis (characterized by eosinophilic inflammation of the airway without obstruction or hyperreactivity demonstrable in spirometry)
• Early bronchogenic carcinoma located in the central airways (irritation of cough receptors due to early tumor growth).

Initial workup

Digital chest x-ray in two projections (first step required); Forced spirometry with bronchodilator test; Cough monitoring and trial of ACEI withdrawal for a minimum of 4 weeks; 24-hour esophageal pH-metry; Eosinophil count in induced sputum.

Standard management

• Enalapril or Lisinopril — discontinue immediately and replace with an angiotensin II receptor antagonist such as Losartan 50 mg orally daily if the cause
• Budesonide — inhaled, 200-400 micrograms every 12 hours if variant asthma or eosinophilic bronchitis is suspected
• Levodropropicin — peripherally acting cough suppressant, 60 mg orally every 8 hours for short-term symptomatic control
• Codeine (15-30 mg orally every 8 hours as a centrally acting alternative).