What is the best treatment for a lingering cough after a respiratory tract infection?

Treatment for Lingering Cough After Respiratory Tract Infection

For lingering cough after a respiratory tract infection, inhaled ipratropium bromide should be tried first as it has demonstrated efficacy in attenuating post-infectious cough in controlled trials. 1

Understanding Post-Infectious Cough

• Post-infectious cough is defined as cough persisting for 3-8 weeks following symptoms of an acute respiratory infection 1
• If cough persists beyond 8 weeks, it should be reclassified as chronic cough and evaluated for other causes 2, 1
• Diagnosis is clinical and one of exclusion, requiring careful assessment of potential underlying factors 2

Treatment Algorithm

First-Line Therapy

• Inhaled ipratropium bromide is recommended as first-line treatment as it has demonstrated efficacy in attenuating post-infectious cough 2, 1
• Antibiotics have no role in treatment unless there is confirmed bacterial infection, as the cause is typically not bacterial 2, 1
• Dextromethorphan-containing cough remedies may provide symptomatic relief 3, 4
• Honey (for patients over 1 year old) and maintaining adequate hydration can help manage symptoms 3

Second-Line Therapy

• Inhaled corticosteroids should be considered when:
  • Cough adversely affects quality of life 2, 1
  • Cough persists despite use of inhaled ipratropium 2, 1
• The mechanism of inhaled corticosteroids is thought to be suppression of airway inflammation and bronchial hyperresponsiveness 1
• Guaifenesin may help loosen phlegm and thin bronchial secretions to make coughs more productive 5

For Severe Cases

• Oral prednisone (30-40 mg daily) for a short, finite period may be prescribed for severe paroxysms of post-infectious cough 2, 6
• This should only be considered after ruling out other common causes of cough such as upper airway cough syndrome, asthma, or gastroesophageal reflux disease 2
• A typical regimen starts with 30-40 mg of prednisone in the morning, tapering to zero over 2-3 weeks 2

When Other Measures Fail

• Central-acting antitussive agents such as codeine and dextromethorphan should be considered when other treatments fail 2, 7
• These medications may cause side effects such as drowsiness, nausea, constipation, and potential for physical dependence 8
• The efficacy of some over-the-counter symptomatic antitussives is often no better than placebo, so prescription options may be necessary for severe cases 7, 9

Special Considerations

• When cough lasts ≥2 weeks with paroxysms, post-tussive vomiting, or inspiratory whooping sound, consider pertussis infection 2, 1
• For confirmed or strongly suspected influenza within 48 hours of symptom onset, consider oseltamivir to potentially improve outcomes 3
• Red flags requiring further medical evaluation include hemoptysis, significant breathlessness, prolonged fever, and symptoms persisting beyond three weeks 3

Common Pitfalls to Avoid

• Failing to recognize when post-infectious cough has persisted beyond 8 weeks, which requires reclassification as chronic cough 2, 1
• Inappropriate use of antibiotics for non-bacterial causes of post-infectious cough 2, 1
• Overlooking underlying conditions that may contribute to persistent cough (asthma, upper airway cough syndrome, GERD) 2, 1
• Relying solely on over-the-counter medications without adequate evidence of efficacy 9, 10