Treatment for Post-Infectious Cough

Definition and Diagnosis

• 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 pathogenetic factors 3, 4

Treatment Algorithm

First-Line Therapy

• Inhaled ipratropium bromide should be tried first as it has demonstrated efficacy in attenuating post-infectious cough in controlled trials 4, 2, 5
• Antibiotics have no role in treatment unless there is confirmed bacterial infection as the cause is typically not bacterial 3, 4, 5

Second-Line Therapy

• Inhaled corticosteroids should be considered when cough adversely affects quality of life 3
• Inhaled corticosteroids should be considered when cough persists despite use of inhaled ipratropium 3, 2, 5
• The mechanism of inhaled corticosteroids is thought to be suppression of airway inflammation and bronchial hyperresponsiveness 4, 6

For Severe Cases

• Oral prednisone (30-40 mg daily) for a short, finite period may be prescribed for severe paroxysms of post-infectious cough 3, 4, 5
• This should only be considered after ruling out other common causes of cough such as upper airway cough syndrome, asthma, or gastroesophageal reflux disease 4, 2

When Other Measures Fail

• Central-acting antitussive agents such as codeine and dextromethorphan should be considered when other treatments fail 3, 2, 5

Special Considerations

Pertussis (Whooping Cough)

• When cough lasts ≥2 weeks with paroxysms, post-tussive vomiting, or inspiratory whooping sound, consider pertussis infection 3, 7, 1
• Pertussis requires specific diagnosis (nasopharyngeal culture is the gold standard) 8, 9
• Macrolide antibiotics are indicated for confirmed pertussis, and patients should be isolated for 5 days from the start of treatment 8

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 3, 1
• Overlooking underlying conditions that may contribute to persistent cough (asthma, UACS, GERD) 4, 1

Monitoring and Follow-up

• Patients should be followed up within 4-6 weeks after initial evaluation 1
• If cough persists beyond 8 weeks, further evaluation for chronic cough causes is warranted 2, 1
• Treatment response should be assessed using validated cough severity tools 1

Post-Viral Cough Treatment

Pharmacological Interventions

• Dextromethorphan at 60 mg provides maximum cough reflex suppression and is preferred over codeine due to fewer side effects, according to the Thorax journal 10
• Codeine and pholcodine have no greater efficacy than dextromethorphan but carry a much greater adverse side effect profile including drowsiness, nausea, constipation, and physical dependence, as reported in the Thorax journal 10
• Menthol by inhalation provides acute but short-lived cough suppression, as noted in the Thorax journal 10
• First-generation sedating antihistamines may be suitable specifically for nocturnal cough, according to the Thorax journal 10

Simple Supportive Measures

• "Home remedies" such as honey and lemon can be recommended as the simplest and cheapest initial advice, as suggested in the Thorax journal 10
• Simple voluntary suppression of cough may be sufficient to reduce cough frequency through central modulation of the cough reflex, as reported in the Thorax journal 10

Definition and Diagnostic Evaluation of Post‑Viral Cough

Definition

• Post‑viral cough is defined as a cough that persists for 3–8 weeks after an acute upper‑respiratory infection in adults. 11

Diagnostic Work‑up When Cough Extends Beyond 8 Weeks

• If cough continues for more than 8 weeks, it should be reclassified as chronic cough and chest radiography plus spirometry are required to assess for underlying pathology. 12