What is the best course of treatment for a 5-month-old infant with croup (laryngotracheobronchitis)?

Treatment of Croup in a 5-Month-Old Infant

For a 5-month-old with croup, administer a single dose of oral dexamethasone 0.15-0.6 mg/kg (maximum 10-12 mg) as first-line treatment, and add nebulized epinephrine (0.5 ml/kg of 1:1000 solution, maximum 5 ml) if there is stridor at rest or respiratory distress. 1, 2

Initial Assessment

• Croup presents with sudden onset of barking cough, stridor, hoarse voice, and respiratory distress without preceding fever or significant respiratory symptoms 1
• Assess severity by presence of stridor at rest and degree of respiratory distress (intercostal retractions, increased work of breathing) 3
• Radiographic studies are unnecessary and should be avoided unless considering alternative diagnoses like bacterial tracheitis or foreign body aspiration 1, 2

Treatment Algorithm by Severity

Mild Croup (No Stridor at Rest)

• Oral dexamethasone 0.15-0.6 mg/kg as a single dose 2, 3
• Observe for 2-3 hours to ensure symptoms improve 4
• No nebulized treatments needed 4

Moderate to Severe Croup (Stridor at Rest or Respiratory Distress)

• Oral dexamethasone 0.15-0.6 mg/kg PLUS nebulized epinephrine 0.5 ml/kg of 1:1000 solution (maximum 5 ml) 2, 4
• Critical: Observe for at least 2 hours after the last epinephrine dose due to short-lived effect (1-2 hours) and risk of rebound symptoms 1, 4
• Administer oxygen to maintain saturation ≥94% if hypoxemic 1, 2

Special Considerations for Infants <6 Months

• At 5 months of age, this infant falls into a higher-risk category requiring closer monitoring 2
• Age <18 months is a criterion for considering hospitalization 2
• Minimal handling reduces metabolic and oxygen requirements 1, 2
• Ensure parents can recognize worsening symptoms and return if needed 2

Hospitalization Criteria

Admit if any of the following are present:

• Need for ≥3 doses of nebulized epinephrine 1, 2, 4
• Oxygen saturation <92% 2
• Age <18 months (which applies to this 5-month-old) 2
• Respiratory rate >70 breaths/min 2
• Persistent difficulty breathing despite treatment 2

Critical Pitfalls to Avoid

• Never discharge within 2 hours of nebulized epinephrine administration due to rebound risk 2, 4
• Do not use nebulized epinephrine in outpatient settings where immediate discharge is planned 1, 2
• Do not withhold corticosteroids even in mild cases 2
• Avoid blind finger sweeps if foreign body aspiration is suspected, as this may push objects deeper 1
• Do not use antibiotics routinely—croup is viral 2
• Cold air and humidified air lack evidence of benefit 1, 2

Discharge Criteria (If Not Hospitalized)

• Resolution of stridor at rest 2, 4
• Minimal or no respiratory distress 2, 4
• Adequate oral intake 2, 4
• Reliable family able to monitor and return if worsening 1, 2
• Follow-up with primary care if not improving within 48 hours 1, 2

Alternative Corticosteroid Options

• If oral dexamethasone cannot be tolerated, nebulized budesonide 2 mg is an alternative 3, 5
• Intramuscular dexamethasone 0.6 mg/kg is another option for children unable to take oral medication 6, 5

Given this infant's young age (5 months), there should be a low threshold for hospitalization, particularly if more than one dose of epinephrine is required or if the family's ability to monitor is uncertain. 1, 2