I have a dry chronic cough lasting longer than eight weeks that has not improved with a short‑acting β‑agonist inhaler; what are the recommended evaluation and management steps?

Systematic Evaluation and Treatment for Chronic Dry Cough Unresponsive to β-Agonist

Your dry chronic cough lasting >8 weeks that hasn't responded to a short-acting β-agonist requires a systematic diagnostic workup to identify the most common treatable causes: upper airway cough syndrome (33%), asthma (16%), gastroesophageal reflux disease, and nonasthmatic eosinophilic bronchitis (5%), before considering this as unexplained chronic cough. 1

Immediate Red Flag Assessment

First, screen for life-threatening conditions requiring urgent evaluation 1:

• Hemoptysis (blood in cough)
• Smoker >45 years with new or changed cough
• Prominent dyspnea at rest or night
• Hoarseness persisting
• Systemic symptoms: fever, weight loss, peripheral edema
• Trouble swallowing or recurrent vomiting
• Recurrent pneumonia

If any red flags present, obtain chest CT and specialist referral immediately.

Essential Initial Diagnostic Tests

Obtain these baseline studies before empiric treatment 2, 3:

• Chest radiograph (to exclude masses, interstitial disease, bronchiectasis)
• Spirometry with bronchodilator response (to detect asthma/COPD)
• Exhaled nitric oxide (FeNO) if available (elevated suggests eosinophilic inflammation)
• Blood eosinophil count (helps identify eosinophilic conditions)
• Validated cough severity tool (Leicester Cough Questionnaire or Cough Severity VAS) 1

Medication and Environmental Review

Before proceeding further 1:

• Discontinue ACE inhibitors if taking (can cause chronic cough in up to 20% of users; may take 4 weeks to resolve after stopping)
• Discontinue sitagliptin if applicable
• Assess environmental/occupational exposures (dust, chemicals, irritants)
• Confirm smoking cessation if applicable

Empiric Treatment Algorithm

Since your β-agonist trial failed, proceed with targeted empiric therapy based on the most common causes 1, 4:

First-Line Empiric Trials (4-6 weeks each):

1. Upper Airway Cough Syndrome (most common at 33%)

• First-generation antihistamine + decongestant (e.g., chlorpheniramine-pseudoephedrine)
• Look for: postnasal drip sensation, throat clearing, nasal congestion

2. Asthma/Eosinophilic Bronchitis (combined 21%)

• Inhaled corticosteroid (moderate-high dose for 4-6 weeks)
• Consider if: positive bronchodilator response on spirometry, elevated FeNO, elevated blood eosinophils
• Important caveat: If spirometry is normal AND FeNO/eosinophils are normal, do NOT use inhaled corticosteroids as they are ineffective for unexplained chronic cough 5

3. Gastroesophageal Reflux Disease

• Lifestyle modifications + proton pump inhibitor (PPI) for 8-12 weeks
• Look for: heartburn, regurgitation, worse when lying down
• Critical note: Acid suppression alone is no longer recommended as sole therapy 1; if no reflux symptoms present, do not use PPIs 5

Follow-up Protocol

Schedule clinic or telephone follow-up within 4-6 weeks after initiating each empiric trial 1. Reassess cough severity using the validated tool to objectively measure response.

When Empiric Trials Fail: Unexplained Chronic Cough

If diagnostic workup is unrevealing and supervised therapeutic trials according to guidelines fail, you have unexplained chronic cough (UCC) 5. This represents cough hypersensitivity syndrome with features like:

• Triggered by non-tussive stimuli (talking, laughing, temperature changes)
• Laryngeal paresthesia (throat tickle, irritation)
• Disproportionate cough to triggers

Treatment for Unexplained Chronic Cough:

1. Multimodal Speech Pathology Therapy (First-line recommendation)

• This is the primary suggested treatment for UCC 5
• Includes cough suppression techniques, breathing exercises, laryngeal hygiene
• Evidence shows improvement in cough severity and quality of life 6

2. Gabapentin (Second-line pharmacologic option)

• Dosing: Start 300 mg once daily, escalate as tolerated up to 1,800 mg/day in divided doses 5
• Reassess risk-benefit at 6 months before continuing
• Side effects: dizziness, somnolence, peripheral edema
• Improves cough-related quality of life in randomized trials
• Alternative: Pregabalin or low-dose morphine (off-label) 2, 3

3. What NOT to do in UCC:

• Do NOT prescribe inhaled corticosteroids if bronchial hyperresponsiveness testing and eosinophil markers are negative 5
• Do NOT prescribe PPIs if acid reflux workup is negative 5

Refractory Cough Management

If symptoms persist despite above measures 1:

• Refer to specialized cough clinic for comprehensive evaluation
• Consider emerging P2X3 receptor antagonists (gefapixant, camlipixant) in clinical trials 2
• Ensure patient compliance with prior treatments was adequate
• Consider multiple simultaneous causes (occurs in significant proportion)

Important Clinical Pitfalls

1. Don't assume asthma without objective evidence: A failed β-agonist trial suggests this may NOT be asthma; confirm with spirometry and bronchial hyperresponsiveness testing
2. Don't over-test initially: Bronchoscopy, CT chest, and nasendoscopy are reserved for red flags or failed empiric therapy 4, 3
3. Don't underestimate speech therapy: Recent evidence shows 56% of patients achieve ≥30% reduction in objective cough frequency with guideline-based therapy, though 71% still report insufficient control 6
4. Don't forget combination causes: Up to 62% of chronic cough patients have multiple contributing factors 1

The reality is that despite optimal guideline-based management, most patients with refractory chronic cough fail to achieve complete symptom control, highlighting substantial unmet therapeutic need 6.