How do you manage a case of subacute cough?

Management of Subacute Cough

For patients with subacute cough (lasting 3-8 weeks), first determine if it is postinfectious or not, then treat accordingly with a sequential approach targeting the most likely causes. 1

Initial Assessment

• Perform a focused history to identify key factors: ACE inhibitor use, smoking status, and signs of serious systemic disease 1, 2
• Classify the cough duration (subacute = 3-8 weeks) to guide your diagnostic approach 2, 3
• Determine if the cough is postinfectious (following a recent respiratory infection) or non-infectious in origin 1
• Assess for signs of respiratory distress including increased respiratory rate, intercostal retractions, or cyanosis 2

Management Algorithm for Subacute Cough

Step 1: Rule out serious conditions

• Obtain a chest radiograph if pneumonia is suspected based on clinical findings such as tachypnea, abnormal lung findings, or hypoxemia 2, 4
• Consider discontinuing ACE inhibitors if the patient is taking them 1, 4
• Counsel and assist with smoking cessation if applicable 1

Step 2: For postinfectious cough

• Determine the likely mechanism: upper airway cough syndrome (UACS), transient bronchial hyperresponsiveness, asthma, pertussis, or acute exacerbation of chronic bronchitis 1
• Start with an oral first-generation antihistamine/decongestant combination for UACS or postnasal drip 1, 2, 4
• Consider inhaled bronchodilators if bronchial hyperresponsiveness is suspected 4, 5
• For suspected pertussis, consider appropriate antibiotics 6
• Note that many cases of postinfectious cough will resolve spontaneously without treatment 5

Step 3: For non-infectious subacute cough

• Manage the same way as chronic cough with a systematic approach 1
• Evaluate for common causes: UACS, asthma, non-asthmatic eosinophilic bronchitis (NAEB), and gastroesophageal reflux disease (GERD) 1, 3, 7
• Apply therapy in sequential and additive steps as multiple causes may be present 1

Specific Diagnostic Tests to Consider

• If asthma is suspected and spirometry doesn't show reversible airflow obstruction, perform bronchoprovocation challenge (BPC) 1, 5
• If BPC testing is unavailable, consider an empiric trial of anti-asthma therapy 1
• For suspected NAEB, perform induced sputum testing for eosinophils if available 1
• If induced sputum testing is unavailable, consider an empiric trial of inhaled corticosteroids 1, 4

Treatment Approach

• For UACS: First-generation antihistamine/decongestant combination 1, 4
• For asthma or bronchial hyperresponsiveness: Inhaled bronchodilators and inhaled corticosteroids 4, 5
• For NAEB: Inhaled corticosteroids 4
• For GERD: Appropriate anti-reflux therapy 7

Common Pitfalls to Avoid

• Don't rely solely on cough characteristics for diagnosis as they have limited diagnostic value 4
• Avoid using antibiotics for viral causes of subacute cough 6
• Don't use newer generation non-sedating antihistamines for cough as they are less effective than first-generation antihistamines 4
• Don't forget to consider pertussis in the differential diagnosis of subacute cough 3, 5
• If cough persists despite appropriate treatment, consider high-resolution CT scan and bronchoscopic evaluation for uncommon causes 1, 4