Recommended Dexamethasone Dose for Croup
The recommended dose of dexamethasone (Decadron) for croup is 0.6 mg/kg as a single dose, with a maximum of 10-16 mg, administered orally, intramuscularly, or intravenously. 1, 2
Dosing Algorithm
Standard Dosing
- Administer 0.6 mg/kg as a single dose (maximum 10-16 mg) 1, 2, 3
- All three routes (oral, IM, IV) are equally effective 3
- Oral administration is preferred when the child can tolerate it, as it avoids injection pain and is equally effective 3
Lower Dose Alternative
- 0.15 mg/kg (maximum 3 mg) is equally effective as 0.6 mg/kg for mild to moderate croup 4, 5, 6
- This lower dose reduces return visits to medical care and provides similar symptom relief 6
- For hospitalized children with moderate to severe croup, both 0.15 mg/kg and 0.6 mg/kg produce equivalent reductions in croup scores with no difference in time to clinical improvement 4
Clinical Context and Timing
Onset and Duration
- Clinical effects begin as early as 30 minutes after administration 3
- Duration of action is approximately 24-72 hours 3
- No tapering is required and single-dose administration does not cause significant adrenal suppression 3
Severity-Based Management
- For all cases of croup (mild, moderate, or severe), administer oral corticosteroids immediately 1, 2
- For moderate to severe croup with stridor at rest or respiratory distress, add nebulized epinephrine 0.5 mL/kg of 1:1000 solution (maximum 5 mL) 1, 2
- Nebulized epinephrine provides immediate but short-lived relief (1-2 hours), while dexamethasone provides longer-lasting benefit 1, 2
Critical Pitfalls to Avoid
Observation Requirements
- Never discharge a patient within 2 hours of nebulized epinephrine administration due to risk of rebound symptoms 1, 2
- Monitor for at least 2 hours after the last dose of nebulized epinephrine before considering discharge 1
Hospitalization Criteria
- Consider admission after 3 doses of nebulized epinephrine (not the traditional 2 doses), which reduces hospitalization rates by 37% without increasing adverse outcomes 2, 3
- Other admission criteria include oxygen saturation <92%, age <18 months, respiratory rate >70 breaths/min, or persistent difficulty breathing 2
Alternative Corticosteroid Options
- Nebulized budesonide 2 mg is equally effective as oral dexamethasone when oral administration is not feasible 2, 7
- Do not use nebulized corticosteroids from hand-held inhalers with spacers—they are ineffective for croup 3
Practical Considerations
- The 0.6 mg/kg dose is the most widely studied and recommended in guidelines, though lower doses (0.15-0.3 mg/kg) have proven equally effective in research studies 1, 2, 4, 5, 6
- For a child weighing 38 kg, the calculated dose would be 22.8 mg, but this is capped at the maximum dose of 16 mg 3
- Antibiotics, antihistamines, and decongestants have no proven effect on viral croup 8
- Cold air and humidified air treatments lack evidence of benefit 1, 2