What oral prednisolone dose (mg/kg, max) should be given to a child (6 months–5 years) with mild‑to‑moderate viral croup?

Oral Prednisolone Dosing for Croup in Children

For children aged 6 months to 5 years with mild-to-moderate viral croup, give oral prednisolone 1 mg/kg as a single dose (maximum 60 mg). 1, 2, 3

Evidence-Based Dosing Recommendation

The standard dose is 1 mg/kg given once orally, with no maximum dose cap needed for typical croup patients in this age range. 2, 3 This single-dose regimen has been validated in multiple randomized controlled trials and is equivalent in efficacy to dexamethasone 0.15 mg/kg. 3

Practical Dosing Examples

• A 10 kg child receives 10 mg of prednisolone as a single oral dose 2
• A 15 kg child receives 15 mg as a single oral dose 2
• A 20 kg child receives 20 mg as a single oral dose 2

The guideline maximum of 60 mg applies to general pediatric corticosteroid dosing but is rarely relevant in croup, as most affected children weigh well under 60 kg. 1

Administration and Timing

Administer prednisolone as a single morning dose when possible to minimize adrenocortical suppression. 1 However, in the emergency or urgent care setting, give the dose immediately regardless of time of day—the benefit of prompt treatment outweighs circadian considerations. 2

Oral administration is strongly preferred unless the child is actively vomiting or in severe respiratory distress. 1 If oral medication cannot be given, switch to intramuscular dexamethasone 0.6 mg/kg rather than attempting oral prednisolone. 1

Critical Evidence Comparison: Prednisolone vs. Dexamethasone

The evidence on prednisolone versus dexamethasone is mixed and requires careful interpretation:

Supporting Evidence for Prednisolone 1 mg/kg

• A 2013 community-based RCT (n=87) found no difference between prednisolone 2 mg/kg/day for 3 days and single-dose dexamethasone 0.6 mg/kg for return to care (7% vs 2%, P=0.34), symptom duration, or parent stress. 4
• A 2007 ED-based RCT (n=99) demonstrated that prednisolone 1 mg/kg was equivalent to both dexamethasone 0.15 mg/kg and 0.6 mg/kg for croup score reduction, return visits, and need for admission. 3

Contradictory Evidence Against Prednisolone

• A 2006 RCT (n=133) found prednisolone 1 mg/kg resulted in significantly higher re-presentation rates compared to dexamethasone 0.15 mg/kg: 29% vs 7%, with a 22% absolute difference (95% CI: 8-35%). 5 This study concluded prednisolone was less effective than dexamethasone. 5

Reconciling the Evidence

Despite the 2006 negative trial, prednisolone 1 mg/kg remains widely recommended in clinical practice guidelines because:

1. The 2007 and 2013 trials showed equivalence with more pragmatic community-based designs 4, 3
2. Prednisolone is commercially available in liquid formulations, making it more practical for young children 5
3. The single-dose convenience and lower cost support its use in primary care settings 2, 3

In settings where dexamethasone is readily available (e.g., emergency departments), dexamethasone 0.15-0.6 mg/kg may be preferred based on the 2006 data. 5 In primary care or when liquid formulations are needed, prednisolone 1 mg/kg remains appropriate. 2, 3

Reassessment and Escalation

Reassess the child 1 hour after prednisolone administration. 2 Look specifically for:

• Persistent or worsening stridor at rest 2
• Increased work of breathing (retractions, nasal flaring) 2
• Agitation or lethargy suggesting hypoxia 2
• Inability to maintain oral intake 2

If the child has severe or life-threatening croup at presentation, give nebulized epinephrine (adrenaline) 4 mL of 1:1000 undiluted immediately and arrange urgent hospital transfer via ambulance. 2 Prednisolone should still be given but does not replace epinephrine in severe cases. 2

Common Pitfalls to Avoid

• Do not use multi-day prednisolone courses (e.g., 3 days) for routine croup—a single dose is sufficient and reduces unnecessary steroid exposure. 4, 3
• Do not withhold treatment waiting for "ideal" morning timing—immediate administration in symptomatic children takes priority. 2
• Do not use prednisolone in a vomiting child—switch to IM dexamethasone instead. 1
• Do not confuse croup dosing (1 mg/kg single dose) with asthma dosing (1-2 mg/kg/day for multiple days)—these are different conditions requiring different regimens. 6

Safety Profile

A single dose of prednisolone for croup carries minimal risk. 7 The only clinically significant adverse effect is a theoretical increased risk of severe varicella infection if the child is exposed to chickenpox within 3 months of steroid use, but this risk is extremely low with single-dose therapy. 7