What is the appropriate evaluation and management for an adult presenting with a cough without red‑flag symptoms?

Evaluation and Management of Adult Cough Without Red‑Flag Symptoms

Initial Classification and Triage

For an adult presenting with cough and no red‑flag symptoms, immediately classify the cough by duration—acute (<3 weeks), subacute (3–8 weeks), or chronic (>8 weeks)—because this single determination dictates the entire diagnostic and therapeutic pathway. 1

Acute Cough (<3 weeks)

• Acute cough is most commonly caused by viral upper respiratory tract infection and is self‑limiting, requiring only reassurance and symptomatic management. 2, 3
• Over‑the‑counter preparations may provide subjective benefit, though evidence for specific pharmacological effects is limited. 2
• Do not prescribe antibiotics for uncomplicated acute cough, as most cases are viral. 2
• Dextromethorphan should be stopped and a physician consulted if cough lasts more than 7 days, returns, or occurs with fever, rash, or persistent headache. 4

Subacute Cough (3–8 weeks)

• Post‑infectious cough accounts for approximately 48% of subacute cases and typically resolves without specific therapy. 1
• Consider Bordetella pertussis if the patient has paroxysmal coughing fits, post‑tussive vomiting, or an inspiratory "whoop"; treat immediately with macrolides. 1, 3
• Upper airway cough syndrome (rhinosinus pathology) underlies approximately 33% of subacute coughs. 1

Chronic Cough (>8 weeks)

• Chronic cough is defined as cough persisting longer than 8 weeks and affects 10–20% of adults, with higher prevalence in females and obese individuals. 2, 1
• Quality‑of‑life impairment is comparable to severe COPD. 2

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Mandatory Baseline Evaluation for Chronic Cough

Every adult with chronic cough must undergo chest radiograph and spirometry with bronchodilator testing as non‑negotiable baseline investigations. 2, 1, 5

• The chest radiograph excludes mass lesions, infiltrates, bronchiectasis, interstitial lung disease, and cardiac abnormalities. 1
• Spirometry detects airflow obstruction and assesses reversibility. 1
• Quantify cough severity using visual analog scales or validated cough‑specific quality‑of‑life questionnaires to objectively monitor treatment response. 2, 1, 5

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Essential History Components

• Medication review: Discontinue any ACE inhibitor immediately, as drug‑induced cough resolves within a median of 26 days (up to 40 weeks) after cessation. 1, 6
• Smoking status: Verify current and past tobacco use; smoking‑related cough typically resolves within 4 weeks after cessation. 1, 5
• Occupational and environmental exposures: Systematically assess for workplace irritants (dust, fumes, chemicals) and home environmental factors (mold, pets, indoor air quality). 1, 5
• Sputum production: Significant sputum usually indicates primary lung pathology and requires a different diagnostic approach. 2, 5
• Upper airway symptoms: Probe for post‑nasal drip sensation, throat clearing, nasal congestion, or chronic rhinitis. 1, 5
• Gastroesophageal symptoms: Ask about heartburn, regurgitation, and nocturnal cough, recognizing that GERD‑related cough often occurs without classic GI complaints. 1, 5
• Asthma indicators: Inquire about wheezing, chest tightness, dyspnea that worsens with exercise or cold air, and nocturnal symptoms. 1, 5

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Physical Examination Focus

• Nasal examination: Look for mucosal congestion, polyps, or purulent discharge. 1
• Oropharyngeal examination: Assess for cobblestoning or mucus. 1
• Lung auscultation: Wheezes appearing only on forced expiration or immediately after coughing are characteristic of cough‑variant asthma; crackles may indicate interstitial lung disease, bronchiectasis, or heart failure. 1
• Digital clubbing: Finger clubbing together with productive cough should prompt evaluation for bronchiectasis, interstitial lung disease, or malignancy. 1

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Algorithmic Empiric Treatment Approach

In nonsmokers not taking ACE inhibitors with normal or near‑normal chest radiographs, four conditions—upper airway cough syndrome (UACS), asthma, gastroesophageal reflux disease (GERD), and nonasthmatic eosinophilic bronchitis (NAEB)—account for >90% of chronic cough cases. 1, 5, 3

Step 1: Treat Upper Airway Cough Syndrome (UACS)

• UACS is the single most frequent cause, accounting for 18.6%–81.8% of chronic cough cases. 1
• Initiate a first‑generation antihistamine‑decongestant combination for several weeks. 2, 5
• When prominent upper‑airway symptoms are present, add topical intranasal corticosteroid therapy. 2

Step 2: Evaluate and Treat Asthma

• Asthma underlies 14.6%–41.3% of chronic cough and may present as cough alone. 1
• Normal spirometry does not exclude asthma; perform methacholine bronchial provocation testing in patients with chronic cough, normal spirometry, and no obvious etiology. 2, 1, 5
• Initiate inhaled corticosteroids according to national asthma guidelines. 1
• A 2‑week trial of oral prednisone (30–40 mg daily) helps differentiate eosinophilic airway inflammation; lack of improvement suggests a non‑asthmatic cause. 2, 1
• For cough‑variant asthma refractory to inhaled steroids, add leukotriene‑receptor antagonists rather than long‑acting β‑agonists. 1

Step 3: Treat Gastroesophageal Reflux Disease (GERD)

• GERD contributes to 4.6%–85.4% of chronic cough and often occurs without gastrointestinal symptoms. 1
• Prescribe intensive acid suppression with omeprazole 20–40 mg twice daily before meals for a minimum of 3 months, combined with dietary and lifestyle modifications. 2, 1
• Remove medications that may aggravate reflux (bisphosphonates, nitrates, calcium‑channel blockers, theophylline, progesterone). 1
• Add metoclopramide 10 mg three times daily if response to proton‑pump inhibitors alone is inadequate. 1
• Clinical response may require 2–12 weeks. 1

Step 4: Consider Nonasthmatic Eosinophilic Bronchitis (NAEB)

• NAEB accounts for 6.4%–17.2% of chronic cough cases and is characterized by eosinophilic airway inflammation without airway hyperresponsiveness or variable airflow obstruction. 1
• Inhaled corticosteroids are effective in reducing cough severity in NAEB. 1

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Management of Multiple Etiologies

Up to 67% of chronic cough patients have multiple simultaneous causes; therefore, retain partially effective therapies and employ additive treatment strategies rather than sequential monotherapy. 1

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Follow‑Up and Reassessment

• Schedule a follow‑up visit within 4–6 weeks to reassess cough severity using validated scales and to verify treatment adherence before abandoning a therapeutic trial. 1, 5, 6
• Formal quantification of treatment response using validated cough‑severity instruments is mandatory. 2, 1

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When to Obtain Advanced Imaging or Specialist Referral

• If all empiric therapies fail after 8 weeks, obtain high‑resolution CT to evaluate for bronchiectasis, interstitial lung disease, or occult masses. 1
• Consider bronchoscopy to assess for endobronchial lesions, sarcoidosis, eosinophilic bronchitis, or occult infection when the comprehensive work‑up remains inconclusive. 1
• Refer to a specialist cough clinic when the condition remains undiagnosed after systematic evaluation of UACS, asthma, NAEB, and GERD. 2, 1, 5

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Management of Refractory (Unexplained) Chronic Cough

• A diagnosis of unexplained chronic cough should be made only after comprehensive evaluation in a specialized cough clinic. 2
• Multimodality speech pathology therapy is suggested as a treatment option for unexplained chronic cough. 2
• Gabapentin is suggested as a therapeutic trial; begin at 300 mg once daily and escalate as tolerated up to a maximum of 1,800 mg daily in two divided doses, with reassessment of the risk‑benefit profile at 6 months. 2, 7
• Low‑dose morphine is preferred over gabapentin or pregabalin for refractory chronic cough. 7
• Do not prescribe inhaled corticosteroids in patients with unexplained chronic cough and negative tests for bronchial hyperresponsiveness and eosinophilia. 2
• Do not prescribe proton pump inhibitor therapy in patients with unexplained chronic cough and a negative workup for acid gastroesophageal reflux disease. 2

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Common Pitfalls to Avoid

• Assuming a single etiology: Up to 40%–67% of chronic cough patients have multiple concurrent causes; combination therapy is often required. 1
• Neglecting medication review: Failure to discontinue ACE inhibitors before extensive work‑up can lead to unnecessary investigations. 1, 6
• Relying solely on acid suppression for GERD‑related cough: Comprehensive management (lifestyle modification, dietary changes, possible prokinetics) is necessary. 1
• Not quantifying cough severity: Use validated cough severity or quality‑of‑life instruments to objectively assess treatment response. 1
• Inadequate trial duration: Empiric therapeutic trials should be maintained for 4–6 weeks before deeming them ineffective. 1, 5
• Inappropriate use of antibiotics: Do not prescribe antibiotics for viral or post‑infectious cough. 2, 6