What is the definition of a recurrent cough in an adult patient with a history of chronic obstructive pulmonary disease (COPD) or other respiratory diseases?

Definition of Recurrent Cough

The term "recurrent cough" is not formally defined in clinical guidelines; instead, cough is classified by duration as acute (<3 weeks), subacute (3-8 weeks), or chronic (>8 weeks), with the understanding that patients may experience multiple episodes of acute cough. 1

Standard Cough Classification by Duration

The British Thoracic Society and other major respiratory societies classify cough based on temporal patterns rather than recurrence 1:

• Acute cough: Duration less than 3 weeks, typically associated with viral upper respiratory tract infections and generally self-limiting 1
• Subacute cough: Duration between 3-8 weeks, often representing post-viral cough 1
• Chronic cough: Duration greater than 8 weeks, requiring systematic evaluation for underlying causes 1, 2, 3

Understanding "Recurrent" in Clinical Context

When patients present with what appears to be "recurrent cough," this clinical pattern warrants specific consideration 4:

• Multiple episodes of acute cough may indicate underlying chronic conditions rather than simple recurrent viral infections, particularly in patients with COPD, asthma, or bronchiectasis 4
• The American College of Chest Physicians specifically recommends considering acute exacerbation of underlying conditions (COPD, asthma, bronchiectasis) rather than simple acute bronchitis in patients with recurrent episodes 4

Special Considerations for COPD Patients

In adults with COPD or other chronic respiratory diseases, what may appear as "recurrent cough" often represents 1:

• Acute exacerbations of the underlying disease: Cough is the commonest symptom associated with acute exacerbations and hospitalizations with COPD 1
• Chronic productive cough: The presence of significant sputum production (productive cough on most days for ≥3 months over ≥2 consecutive years) defines chronic bronchitis, which affects 85-90% of smokers with COPD 5, 6
• Baseline chronic cough with episodic worsening: Rather than truly "recurrent" episodes, these patients have persistent chronic cough that periodically intensifies 1

Clinical Pitfalls to Avoid

Do not mistake recurrent acute exacerbations of chronic respiratory disease for simple recurrent viral infections 4:

• Patients presenting with repeated episodes of cough should undergo chest radiography and spirometry to identify underlying chronic lung disease 1
• In COPD patients, exacerbations are defined as worsening of 2 or more major symptoms (dyspnea, sputum volume, sputum purulence) or worsening of any 1 major symptom with minor symptoms (including increased cough or wheeze) for at least 2 consecutive days 5
• Treatment should target the underlying chronic condition rather than treating each episode as an isolated acute cough 4

Practical Approach

When evaluating a patient with apparent "recurrent cough," determine whether this represents 1, 4:

1. True recurrent acute episodes (multiple self-limited episodes <3 weeks each with complete resolution between episodes) - most commonly viral URTIs occurring 2-5 times per adult per year 1
2. Chronic cough (continuous symptoms >8 weeks) that the patient perceives as "recurrent" due to fluctuating severity 1, 2, 3
3. Recurrent exacerbations of underlying chronic respiratory disease (COPD, asthma, bronchiectasis) requiring adjustment of maintenance therapy 4, 5

The distinction is critical because management differs fundamentally: acute viral cough requires supportive care only, while chronic cough and exacerbations of chronic disease require specific diagnostic evaluation and disease-directed therapy 1, 4, 3.