What is the management approach for eosinophilic bronchitis?

Management of Eosinophilic Bronchitis

Inhaled corticosteroids are the first-line treatment for eosinophilic bronchitis and should be administered for at least 2 months to reduce relapse rates. 1, 2

Diagnosis

Before initiating treatment, confirming the diagnosis is essential:

1. Diagnostic criteria for eosinophilic bronchitis:

   • Chronic cough
   • Normal spirometry
   • No evidence of variable airflow obstruction
   • No airway hyperresponsiveness (negative methacholine challenge test)
   • Sputum eosinophilia (>3%) 1, 3

2. Diagnostic methods:

   • Induced sputum examination is the gold standard for diagnosis
   • Exhaled nitric oxide measurement may be helpful (typically elevated) but has not been formally validated 1

Treatment Algorithm

First-line Treatment:

• Inhaled corticosteroids (e.g., budesonide 400 μg twice daily) 1, 3
• Duration: Minimum 2 months (significantly lower relapse rates compared to 1-month treatment) 2
• Monitor response through:
  • Symptom improvement
  • Reduction in sputum eosinophil count

For Inadequate Response:

• Increase inhaled corticosteroid dose
• Consider oral corticosteroids for refractory cases 1, 4
  • Prednisolone 30 mg/day for 2 weeks is a reasonable trial
  • If no response after this trial, reconsider diagnosis 1

For Occupational Eosinophilic Bronchitis:

• Identify and eliminate exposure to occupational sensitizers 1, 4
• Continue inhaled corticosteroids during avoidance period

Duration of Treatment and Follow-up

• Initial treatment: 2-4 months of inhaled corticosteroids 2
• Follow-up: Reassess with induced sputum examination to confirm resolution of eosinophilia
• Relapse prevention:
  • 3-month treatment course shows significantly lower relapse rates (12%) compared to 1-month treatment (41.9%) 2
  • Consider maintenance therapy in patients with recurrent symptoms

Special Considerations

• Comorbidities: Assess for other causes of chronic cough that may coexist with eosinophilic bronchitis (rhinitis, gastroesophageal reflux) 1
• Occupational factors: Always consider potential occupational exposures as triggers 1, 5
• Monitoring: Regular assessment of sputum eosinophil counts to guide therapy decisions 5

Treatment Efficacy

• Success rate with inhaled corticosteroids is high, with significant improvement in cough symptoms and reduction in sputum eosinophilia 3
• In a study of 12 patients with eosinophilic bronchitis, all improved after treatment with inhaled budesonide 400 μg twice daily, with sputum eosinophil count decreasing from 16.8% to 1.6% 3

Prognosis

• Generally benign course with good response to therapy 4
• Some patients may require long-term inhaled corticosteroid therapy to prevent relapse
• In rare cases, persistent airflow obstruction may develop 4

Pitfalls to Avoid

• Misdiagnosis: Ensure thorough evaluation to differentiate from cough variant asthma (which has airway hyperresponsiveness)
• Inadequate treatment duration: Treating for less than 2 months is associated with higher relapse rates 2
• Failure to consider occupational causes: Always evaluate for workplace exposures that may trigger eosinophilic inflammation 1, 5
• Premature discontinuation: Ensure sputum eosinophilia has resolved before stopping treatment