What is the recommended dose of dexamethasone (corticosteroid) for treating croup?

Dexamethasone Dosing for Croup

For croup, administer a single dose of dexamethasone 0.15 to 0.6 mg/kg (maximum 10-12 mg), with 0.15 mg/kg being equally effective as higher doses for most patients. 1, 2

Recommended Dosing Strategy

Standard dose: 0.15 mg/kg is as effective as higher doses for relieving symptoms and reducing hospitalization duration in children with croup. 2 This lower dose has been directly compared to 0.3 mg/kg and 0.6 mg/kg in randomized controlled trials and showed equivalent efficacy across all outcome measures including:

• Duration of hospitalization 2
• Reduction in croup scores 2
• Need for nebulized epinephrine 2
• ICU admission rates 2

Higher doses (0.6 mg/kg) remain acceptable and are commonly recommended in guidelines, particularly for moderate-to-severe croup, with a maximum dose of 10-12 mg. 1, 3 The 0.6 mg/kg dose was the traditional standard and has extensive evidence supporting its use. 4

Route of Administration

Oral administration is preferred due to ease of use, availability, and low cost. 3 Dexamethasone has equivalent bioavailability between oral and intravenous routes (1:1 conversion). 5

Intramuscular or intravenous routes should be reserved for:

• Patients who are vomiting 3
• Patients in severe respiratory distress unable to tolerate oral medication 3
• When IV administration is used, infuse slowly over several minutes to avoid perineal burning 5

Clinical Application by Severity

All patients with croup (including mild disease) should receive dexamethasone. 1 The evidence supports treating all children presenting for medical assessment with croup symptoms, as corticosteroids reduce hospitalizations, length of illness, and need for subsequent treatments. 3

Moderate-to-severe croup:

• Dexamethasone 0.15-0.6 mg/kg as a single dose 1, 6
• Consider nebulized epinephrine for immediate symptom relief (effect lasts 1-2 hours) 7
• Epinephrine dose: 0.5 ml/kg of 1:1000 solution 7

Mild croup:

• Lower doses (0.15-0.3 mg/kg) may be appropriate 3
• Single dose is sufficient 1

Expected Clinical Response

Symptom improvement occurs within 12-24 hours:

• Significant decline in croup scores by 12 hours post-injection 4
• 85% of patients show improvement (≥2 point reduction in croup score) by 24 hours 4
• Reduced need for repeat epinephrine treatments (19% vs 62% in placebo) 4

Time to clinical improvement:

• Median time to croup score ≤2 is approximately 8 hours 6
• Most symptoms resolve within 2 days 1

Important Clinical Considerations

Nebulized budesonide (500 µg) may reduce symptoms in the first 2 hours but lacks long-term outcome data. 7 It is less commonly used than oral dexamethasone due to convenience and cost factors. 3

Corticosteroid-induced complications are rare in croup treatment. 3 However, antifungal prophylaxis should be considered in patients receiving prolonged steroid therapy. 5

Hospitalization rates are low: Only 1-8% of croup patients require admission, and less than 3% of admitted patients require intubation. 1