What is the appropriate oral prednisone dosing regimen for a 6‑month‑to‑5‑year‑old child with mild‑to‑moderate viral croup when dexamethasone is unavailable?

Prednisone Dosing for Croup

When dexamethasone is unavailable, use oral prednisolone 1 mg/kg as a single dose (maximum 60 mg) for children with mild-to-moderate croup, though this is less effective than dexamethasone and carries a higher risk of return visits. 1

Evidence-Based Dosing Regimen

Standard Single-Dose Protocol

• Administer prednisolone 1 mg/kg orally as a single dose for children aged 6 months to 5 years with mild-to-moderate croup 2
• Maximum dose: 60 mg regardless of weight 3, 4
• Give as a single morning dose before 9 AM to align with physiologic cortisol rhythm 4
• No taper is required for this single-dose regimen 4

Alternative Multi-Day Regimen

• Some evidence supports prednisolone 2 mg/kg/day divided over 3 days (though this is less commonly used than single-dose therapy) 5
• For severe croup requiring intubation, prednisolone 1 mg/kg every 12 hours decreases duration of intubation 2

Critical Performance Limitations

Prednisolone is demonstrably inferior to dexamethasone for croup. 1 In a randomized equivalence trial, children treated with prednisolone 1 mg/kg had a 29% re-presentation rate compared to only 7% with dexamethasone 0.15 mg/kg—a clinically significant 22% absolute difference 1. This means 1 in 5 additional children will require unscheduled return to medical care when treated with prednisolone instead of dexamethasone 1.

The Cochrane systematic review confirms that dexamethasone probably reduces return visits or readmissions by almost half compared to prednisolone (RR 0.55,95% CI 0.28 to 1.11) 6. Additionally, dexamethasone showed a 28% reduction in the need for supplemental glucocorticoids as rescue therapy 6.

Practical Prescribing Details

For a typical 2-year-old weighing 12 kg:

• Dose: 12 mg prednisolone (1 mg/kg × 12 kg) 3, 4
• Using 15 mg/5 mL suspension: Give 4 mL once 3

For a 4-year-old weighing 16 kg:

• Dose: 16 mg prednisolone (1 mg/kg × 16 kg) 3, 4
• Using 15 mg/5 mL suspension: Give 5.3 mL once 3

For overweight children:

• Base dosing on ideal body weight, not actual weight, to avoid unnecessary steroid exposure 3, 4, 7

Why Dexamethasone Remains Superior

Dexamethasone 0.15 mg/kg is the evidence-based first-line treatment for croup 8, 6. This lower dose (0.15 mg/kg) is as effective as higher doses (0.3 or 0.6 mg/kg) in relieving symptoms and reducing hospitalization duration 8. The key advantages of dexamethasone include:

• Longer half-life (36-72 hours vs. 12-36 hours for prednisolone), providing sustained anti-inflammatory effect 2
• Significantly lower return visit rates 1, 6
• Reduced need for rescue corticosteroids 6
• Equivalent or superior symptom reduction at all time points (2,6,12, and 24 hours) 6

Safety Considerations

• Single-dose corticosteroids carry minimal risk in croup management 2
• The only significant potential adverse effect is increased risk of severe varicella infection in non-immune children 2
• No major adverse effects have been documented with single-dose therapy for croup 2
• Common side effects (Cushingoid features, growth deceleration, weight gain) are associated with prolonged use, not single-dose therapy 3

Clinical Algorithm

1. First choice: Dexamethasone 0.15 mg/kg orally (single dose) 8, 6
2. If dexamethasone unavailable: Prednisolone 1 mg/kg orally (single dose, max 60 mg) 1, 2
3. Counsel families that prednisolone may require return visit (29% vs. 7% with dexamethasone) 1
4. Provide clear return precautions given higher failure rate with prednisolone 1
5. Consider arranging dexamethasone for rescue therapy if symptoms worsen 6

Common Pitfall to Avoid

Do not use prednisolone as equivalent to dexamethasone—the evidence clearly demonstrates inferior outcomes 1, 6. While prednisolone is effective compared to placebo 6, it should be reserved only for situations where dexamethasone is truly unavailable, and families should be counseled about the higher likelihood of treatment failure 1.