What is the recommended dose of prednisone (corticosteroid) for a patient with post-infectious cough, considering their overall health status and past medical history, including respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD)?

Prednisone Dosing for Post-Infectious Cough

Prednisone should be reserved as a third-line therapy for post-infectious cough and only prescribed at 30-40 mg daily for 5-10 days when severe paroxysms significantly impair quality of life after first-line and second-line treatments have failed. 1, 2

When to Use Prednisone (Critical Decision Points)

Prednisone is not first-line therapy for post-infectious cough. The American College of Chest Physicians explicitly recommends it only when ALL of the following criteria are met: 2, 3

• Severe paroxysms of cough that significantly impair quality of life (not mild-moderate symptoms) 1, 2
• Failure of inhaled ipratropium bromide (2-3 puffs four times daily for 1-2 weeks) 2, 3
• Failure of inhaled corticosteroids (fluticasone 220 mcg or budesonide 360 mcg twice daily for up to 8 weeks) 2, 3
• Other common causes ruled out or adequately treated (upper airway cough syndrome, asthma, GERD) 2, 3

Correct Dosing When Indicated

When prednisone is appropriate, the dose is: 1, 2

• 30-40 mg orally daily for 5-10 days (not 4-8 mg, which guarantees treatment failure) 1
• Administer in the morning prior to 9 AM to minimize adrenal suppression 4
• Consider antacids between meals if using higher doses 4

This dosing is based on the principle that inadequate steroid doses (4-8 mg) for severe respiratory symptoms will fail, while 30-40 mg provides adequate anti-inflammatory effect for post-infectious airway inflammation. 1

Treatment Algorithm for Post-Infectious Cough

First-Line Treatment

• Inhaled ipratropium bromide 2-3 puffs (17-34 mcg per puff) four times daily 2
• This has the strongest evidence for attenuating post-infectious cough 2
• Expected response time: 1-2 weeks 2

Second-Line Treatment (if quality of life remains affected)

• Inhaled corticosteroids: fluticasone 220 mcg or budesonide 360 mcg twice daily 2
• Allow up to 8 weeks for full response 2
• Mechanism: suppresses airway inflammation and bronchial hyperresponsiveness 2

Third-Line Treatment (only for severe cases)

• Oral prednisone 30-40 mg daily for 5-10 days 1, 2
• Reserved exclusively for severe paroxysms after failure of above therapies 2, 3

Special Populations

Patients with Asthma or COPD

• For cough variant asthma, a diagnostic-therapeutic trial of prednisone 30 mg daily for 2 weeks can establish the diagnosis 3, 5
• In known asthmatics, ensure maintenance therapy is optimized with inhaled corticosteroids and long-acting bronchodilators before considering oral steroids 6, 3
• For COPD patients, post-infectious cough may represent an acute exacerbation requiring temporary intensification of therapy 2
• Complete resolution of asthmatic cough may require up to 8 weeks of inhaled corticosteroids 6

Patients with Severe Symptoms

For severe paroxysms with significant respiratory distress, the American College of Chest Physicians recommends: 1

• Dexamethasone 30-40 mg daily (or methylprednisolone 125-160 mg IV if unable to take oral) for 5-10 days 1
• Optimize bronchodilator therapy with nebulized albuterol 2.5-5 mg every 4-6 hours 1
• Add ipratropium bromide 0.5 mg to each nebulizer treatment 1

Critical Pitfalls to Avoid

Do NOT prescribe prednisone as first-line therapy

• Post-infectious cough requires a stepwise approach starting with ipratropium 2, 3
• Jumping to prednisone for mild-moderate symptoms is inappropriate 2

Do NOT use inadequate doses

• Doses of 4-8 mg dexamethasone (or equivalent prednisone 20-40 mg) are insufficient for severe symptoms 1
• The correct dose for severe cases is 30-40 mg prednisone daily, not lower doses 1, 2

Do NOT prescribe antibiotics

• Antibiotics are explicitly contraindicated for post-infectious cough 2, 3
• The cause is viral, not bacterial, unless there is confirmed bacterial sinusitis or early pertussis 2

Do NOT ignore other causes

• If cough persists beyond 8 weeks, reclassify as chronic cough and systematically evaluate for upper airway cough syndrome, asthma, and GERD 2
• Chronic cough is frequently multifactorial and requires treatment of all contributing causes 2

Evidence Quality and Nuances

The recommendation for 30-40 mg prednisone comes from high-quality guidelines (American College of Chest Physicians, American Thoracic Society) 1, 2, though the evidence base is rated as moderate strength 2. Importantly, a 2017 randomized trial found that oral prednisolone did not reduce symptom duration or severity in adults with acute lower respiratory tract infection without asthma 7, which reinforces that prednisone should only be used in carefully selected cases with severe symptoms after other therapies have failed.

For cough variant asthma specifically, older evidence supports using prednisone 30 mg daily for 1-2 weeks as a diagnostic trial, with subsequent management consisting of inhaled corticosteroids 5. However, this is a distinct entity from simple post-infectious cough.

When to Reassess

• If no improvement within 2 weeks of prednisone, reconsider the diagnosis 3
• If cough persists beyond 8 weeks total duration, reclassify as chronic cough and investigate other causes systematically 2, 3
• Return immediately if fever develops, hemoptysis occurs, or symptoms worsen 2