Can Cough-Variant Asthma Present with Expectoration?
No, cough-variant asthma (CVA) characteristically presents with chronic nonproductive (dry) cough as its sole manifestation, and the presence of significant sputum production should prompt consideration of alternative diagnoses. 1, 2
Defining Features of Cough-Variant Asthma
- CVA is defined by persistent, nonproductive cough lasting >2–3 weeks as the only presenting symptom, without wheezing or dyspnea. 3, 1
- The American College of Chest Physicians explicitly states that chronic nonproductive cough is the primary manifestation and key diagnostic criterion for CVA. 1
- Physical examination and spirometry may be entirely normal at rest, making CVA challenging to diagnose but not excluding the condition. 1, 2
Why Sputum Production Argues Against CVA
- The medical history regarding sputum production has little diagnostic value for distinguishing causes of chronic cough, but the absence of sputum is characteristic of CVA specifically. 3
- Even when patients with chronic cough report significant bronchorrhea (excessive mucus production), the underlying cause in nonsmokers with normal chest X-rays is typically upper airway cough syndrome (UACS), gastroesophageal reflux disease (GERD), or classic asthma—not CVA. 3
- CVA shares pathophysiological features with classic asthma including eosinophilic airway inflammation, but it distinctly lacks the productive cough seen in other respiratory conditions. 4, 5
Alternative Diagnoses to Consider When Sputum Is Present
Non-Asthmatic Eosinophilic Bronchitis (NAEB)
- NAEB presents with chronic cough and eosinophilic inflammation but lacks airway hyperresponsiveness on methacholine testing, distinguishing it from CVA. 1, 6
- NAEB accounts for 13–33% of chronic cough cases in various series and can present with productive cough, unlike CVA. 3, 7
Classic Asthma
- Classic asthma may present with productive cough along with wheezing and dyspnea, features that are absent in CVA by definition. 3, 5
Upper Airway Cough Syndrome (UACS)
- UACS can present as "silent post-nasal drip syndrome" where cough may be accompanied by mucus production from upper airway inflammation. 3, 8
Clinical Approach to the 35-Year-Old Woman with 30-Day Cough
For this specific patient:
- A 30-day dry cough fits the CVA timeline (>2–3 weeks), but if she is producing sputum, CVA becomes less likely. 3, 1
- Methacholine inhalation challenge testing should be performed when history, physical examination, and spirometry are non-diagnostic; a positive test demonstrates airway hyperresponsiveness characteristic of CVA. 1, 2
- Definitive diagnosis requires documented resolution of cough with anti-asthmatic therapy (inhaled bronchodilators and corticosteroids), with partial improvement after 1 week and complete resolution potentially requiring up to 8 weeks. 1
Common Pitfalls to Avoid
- Do not assume that any chronic cough in an asthmatic patient is CVA—the nonproductive nature of the cough is essential to the diagnosis. 1, 2
- Do not overlook that approximately 30% of CVA patients may progress to classic asthma with typical symptoms including productive cough within several years if inadequately treated. 1, 4
- Remember that purulent sputum does not indicate bacterial infection in acute bronchitis and results from inflammatory cells, but its presence still argues against CVA as the primary diagnosis. 3