What diseases produce a productive cough?

Diseases That Produce Productive Cough

The primary diseases causing productive cough are bronchiectasis, chronic bronchitis/COPD, asthma, protracted bacterial bronchitis (in children and possibly adults), and immunodeficiencies, with bronchiectasis being the most important to identify due to its specific treatment implications. 1

Major Causes of Productive Cough

Bronchiectasis

• Bronchiectasis is characterized by chronic productive cough as its cardinal feature, with permanent bronchial dilation leading to mucus retention and recurrent infections 1, 2
• Patients typically present with daily cough and sputum production, often purulent or mucopurulent in nature 1, 2
• The condition affects approximately 500,000 people in the US, with prevalence increasing substantially with age (812 per 100,000 in those ≥75 years) 2
• Common pathogens isolated include Haemophilus influenzae, Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa 1
• Diagnosis requires high-resolution CT scanning showing dilated airways (signet ring sign), airway thickening, and mucus plugging 1, 2
• Associated conditions include rheumatoid arthritis, inflammatory bowel disease, α1-antitrypsin deficiency, primary ciliary dyskinesia, and immunodeficiency syndromes, though up to 38% of cases are idiopathic 1, 2

Chronic Bronchitis and COPD

• Chronic productive cough defines chronic bronchitis and is present in 100% of these patients 3
• COPD patients commonly report cough in association with phlegm production and breathlessness 1
• A productive cough in patients with established airflow obstruction predicts lung function decline 1
• Smokers with persistent cough are at increased risk of developing COPD 1

Asthma

• Asthma can present with productive cough, though it is more commonly associated with dry cough 1
• The cough may be accompanied by wheezes and prolonged expiratory phase on auscultation 1
• Conditions associated with productive cough include bronchiectasis (29% of cases have concurrent asthma) 2

Protracted Bacterial Bronchitis (PBB)

• In children ≤14 years with chronic wet cough (>4 weeks) without underlying disease, PBB should be diagnosed if cough resolves within 2 weeks of antibiotics targeting Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1
• If wet cough persists after 2 weeks of appropriate antibiotics, an additional 2 weeks of treatment is recommended 1
• After 4 weeks of failed antibiotic therapy, further investigations including flexible bronchoscopy with quantitative cultures and/or chest CT should be undertaken 1
• An adult version of PBB has been proposed for patients with idiopathic chronic productive cough who respond to low-dose macrolide therapy 4

Immunodeficiencies

• Primary antibody deficiency syndromes (such as common variable immunodeficiency) can present with chronic productive cough and recurrent infections 1, 2
• These conditions have important therapeutic and prognostic implications requiring immunoglobulin quantification testing (IgG, IgA, IgE, IgM) 2

Less Common but Important Causes

Infectious Etiologies

• Pertussis infection can cause persistent productive cough, with 10% of chronic cough cases having positive nasal swabs for Bordetella 1
• Nontuberculous mycobacterial infections (particularly Mycobacterium avium complex) and tuberculosis can cause bronchiectasis with productive cough 1, 2
• Allergic bronchopulmonary aspergillosis (ABPA) presents with productive cough and isolation of Aspergillus species 1

GERD-Induced Bronchitis

• GERD can present as a cough-phlegm syndrome similar to chronic bronchitis, with either productive or dry cough 5
• GERD is "silent" from a GI standpoint in up to 75% of cases, with patients presenting with respiratory symptoms only 5
• Aspiration syndromes associated with GERD include bacterial pneumonia, chemical pneumonitis, recurrent bacterial pneumonias, bronchiectasis, and tracheobronchitis 5
• Bronchoscopy may reveal hemorrhagic tracheobronchitis and erythema of subsegmental bronchi 5

Lung Cancer

• Cough is the fourth most common presenting feature of lung cancer and may be productive 1
• The presence of finger clubbing in a smoker with pleural effusion or lobar collapse strongly suggests bronchogenic carcinoma 1

Non-Asthmatic Eosinophilic Bronchitis

• This condition can cause chronic productive cough and may be clinically unsuspected initially 1, 4

Critical Diagnostic Considerations

When to Suspect Bronchiectasis

• Consider investigation for bronchiectasis in patients with persistent production of mucopurulent or purulent sputum, particularly with relevant risk factors 1
• Investigate patients with rheumatoid arthritis who have chronic productive cough or recurrent chest infections 1
• In COPD patients with frequent exacerbations (≥2 annually) and previous positive sputum culture for P. aeruginosa while stable, investigate for bronchiectasis 1
• Consider investigation in patients with inflammatory bowel disease and chronic productive cough 1

Red Flags Requiring Urgent Evaluation

• Chronic productive purulent cough is always pathological and requires detailed evaluation 1
• Digital clubbing, hemoptysis, or constitutional symptoms warrant immediate investigation 1
• Coughing with feeding suggests aspiration and requires swallowing evaluation 1

Common Pitfalls to Avoid

• Do not assume productive cough has the same differential diagnosis as dry cough—the approach should focus on conditions most likely to cause sputum production 4
• The prevalence of bronchiectasis among patients with productive cough attending specialist clinics is only 4%, so other causes must be systematically excluded 1
• Coarse crackles on examination suggest bronchiectasis, but their absence does not exclude the diagnosis—HRCT is required 1
• Sputum cultures positive for common respiratory pathogens are not specific for bronchiectasis, as they may also occur in chronic bronchitis 1