What is the recommended dose of dexamethasone (DEX) for a 2-year-old child weighing 27 pounds with symptoms of croup?

Dexamethasone Dosing for Croup in a 2-Year-Old Weighing 27 Pounds

Administer dexamethasone 0.6 mg/kg as a single oral dose (maximum 16 mg), which equals approximately 7.4 mg for this 27-pound (12.3 kg) child. 1

Dose Calculation

• Weight conversion: 27 pounds = 12.3 kg
• Standard dose: 0.6 mg/kg × 12.3 kg = 7.4 mg 1
• Maximum dose cap: 16 mg (not applicable for this child) 1
• Volume: Using standard dexamethasone concentration (4 mg/mL), this equals approximately 1.85 mL

Route of Administration

• Oral route is preferred when the child can tolerate it, as it is equally effective as intramuscular or intravenous administration and avoids the pain of injection 1
• All three routes (oral, IM, IV) demonstrate equal efficacy for croup treatment 1
• Oral administration is simpler and more practical in most clinical settings 1

Alternative Dosing Consideration

While 0.6 mg/kg is the standard recommended dose 1, emerging evidence suggests that 0.15 mg/kg may be equally effective 2, 3, 4. This lower dose (approximately 1.85 mg for this child) offers benefit as early as 30 minutes post-administration 3 and may reduce concerns about potential side effects 3. However, the 0.6 mg/kg dose remains the guideline-recommended standard 1, 5, particularly for moderate to severe croup where you want to ensure maximal efficacy.

Onset and Duration of Action

• Onset: Clinical improvement begins as early as 30 minutes after administration 3, though traditional teaching suggested 4-6 hours 5
• Duration: Single-dose dexamethasone provides relief for approximately 24-72 hours 1
• No tapering required: The single-dose regimen does not cause significant adrenal suppression and requires no taper 1

Adjunctive Therapy for Moderate to Severe Croup

If this child presents with stridor at rest, significant retractions, or respiratory distress, consider adding:

• Nebulized epinephrine: 0.5 mL/kg of 1:1000 solution (maximum 5 mL) 6, 7
• For this 12.3 kg child: approximately 6 mL, but capped at 5 mL maximum 6
• Critical caveat: Epinephrine provides rapid but temporary relief lasting only 1-2 hours 7, 5
• Mandatory observation: Monitor for at least 2 hours after the last epinephrine dose to assess for rebound symptoms 7, 2

Important Clinical Pitfalls to Avoid

• Never discharge within 2 hours of nebulized epinephrine due to risk of rebound airway obstruction 7, 5, 8
• Do not underdose: Lower steroid dosages (below 0.15 mg/kg) have proven ineffective 5
• Avoid nebulized corticosteroids from hand-held inhalers with spacers—they are ineffective for croup 1
• Do not use humidified or heated air therapy—current evidence shows no benefit 7

Hospitalization Criteria

Consider admission if the child requires:

• ≥3 doses of nebulized epinephrine 7, 2
• Age <18 months with severe symptoms 7
• Oxygen saturation <92-94% 7
• Inability of family to provide appropriate observation 7