How should I evaluate and manage a patient with a persistent deep dry cough?

Evaluation and Management of Persistent Deep Dry Cough

Begin by immediately discontinuing any ACE inhibitor the patient is taking, as this is the single most effective intervention for drug-induced cough and affects 5-35% of patients on these medications. 1

Immediate Medication Review

• Stop ACE inhibitors for at least 4 weeks, as cough may begin hours to over 1 year after drug initiation and typically resolves within 1-4 weeks of cessation (though may persist up to 3 months) 1
• Substitute with an angiotensin receptor blocker (ARB), which is well-tolerated and does not provoke cough recurrence 1
• Review for other medications that may cause cough, including sitagliptin 2

Screen for Red Flag Symptoms Requiring Urgent Evaluation

• Hemoptysis (coughing blood) 2, 1
• Prominent dyspnea, especially at rest or night 2
• Systemic symptoms: fever, night sweats, unexplained weight loss 2, 1
• Smoker >45 years with new or changed cough 2
• Hoarseness or trouble swallowing 2
• Recurrent pneumonia or abnormal chest radiograph 2

Mandatory Baseline Investigations

• Obtain chest radiograph and spirometry as baseline for all patients with chronic cough 1
• If chest X-ray is normal but empiric treatments fail, proceed to high-resolution CT scan to detect subtle parenchymal disease 1

Systematic Treatment Algorithm

Step 1: Upper Airway Cough Syndrome (UACS)

Initiate first-generation antihistamine-decongestant combination (e.g., brompheniramine/pseudoephedrine) plus intranasal corticosteroid spray (e.g., fluticasone or mometasone). 1

• Clinical clues: post-nasal drip sensation, throat clearing, nasal discharge, or cough triggered by talking, laughing, or singing 1
• Expected improvement: days to 1-2 weeks 1
• UACS may present as "silent" disease where cough is the sole symptom without nasal complaints 3

Step 2: Asthma or Eosinophilic Bronchitis

Perform bronchial provocation testing (methacholine challenge) when spirometry is normal to detect airway hyper-responsiveness. 1

• Start inhaled corticosteroids (fluticasone 220 µg or budesonide 360 µg twice daily) plus short-acting β-agonist 1
• Add leukotriene receptor antagonist before escalating to oral steroids 1
• If no response, prescribe oral prednisone 40 mg daily for 5-10 days 1
• Expected improvement: up to 8 weeks 1
• Remember: cough can be the sole manifestation of asthma without wheeze or dyspnea 1
• Clinical clues: cough worsening at night, with cold air exposure, or after exercise 3

Step 3: Gastroesophageal Reflux Disease (GERD)

Begin high-dose proton pump inhibitor therapy (e.g., omeprazole 40 mg twice daily) plus prokinetic agent if PPI alone is inadequate. 1

• Implement dietary modifications: avoid late meals, elevate head of bed, limit fatty foods, caffeine, alcohol, chocolate 1
• Expected improvement: 2 weeks to several months 1
• Clinical clues: cough triggered by eating, post-prandial timing, or phonation (talking, laughing, singing) 1
• "Silent" GERD can produce cough without heartburn or regurgitation 3

Critical Management Principles

• Continue partially effective therapy while adding the next empiric intervention rather than stopping prematurely 1
• Reserve antibiotics only for documented bacterial infection; most persistent dry coughs are non-infectious 1, 3
• Do not dismiss ACE-inhibitor cough based on timing alone, as onset is highly variable 1
• Persistent cough is frequently multifactorial and will not resolve until all contributing conditions are addressed 3

Advanced Evaluation for Refractory Cases

• Perform 24-hour esophageal pH monitoring when GERD is suspected but empiric therapy has failed 1
• Consider bronchoscopy when full diagnostic work-up remains inconclusive, to evaluate for endobronchial lesions, sarcoidosis, or eosinophilic bronchitis 1
• Rule out uncommon causes including pertussis (10% of chronic cough cases), tuberculosis in endemic areas, occupational exposures, and lung cancer 2, 3

Special Considerations

• In endemic areas or high-risk populations, consider tuberculosis even with normal chest radiographs 2
• Evaluate for occupational or environmental exposures routinely, as workplace sensitizers can lead to chronic cough 2
• In immunocompromised patients, expand differential diagnosis based on immune defect type and CD4+ counts 2

Expected Timeline Summary

Condition	Time to Improvement
UACS	Days to 1-2 weeks [1]
Asthma/Eosinophilic bronchitis	Up to 8 weeks [1]
GERD	2 weeks to several months [1]
ACE-inhibitor cessation	1-4 weeks (up to 3 months) [1]

The majority of persistent dry coughs have an identifiable and treatable cause; systematic evaluation with adequate therapeutic trials is more effective than symptomatic suppression alone. 1