What is the recommended management of croup in a 5‑month‑old infant?

Management of Croup in a 5-Month-Old Infant

A 5-month-old infant with croup should receive a single dose of oral dexamethasone 0.15–0.6 mg/kg immediately, with nebulized epinephrine (0.5 mL/kg of 1:1000 solution) added if there is moderate-to-severe respiratory distress with stridor at rest or increased work of breathing. 1, 2

Immediate Assessment

Evaluate the severity of croup by assessing:

• Presence of stridor at rest (indicates moderate-to-severe disease requiring intervention) 2, 3
• Work of breathing: intercostal retractions, suprasternal retractions, nasal flaring 2, 3
• Respiratory rate: tachypnea >50/min in infants suggests severe disease 1
• Oxygen saturation: hypoxemia indicates severe obstruction 1, 3
• Ability to feed: inability to feed suggests significant respiratory compromise 1
• Level of agitation or exhaustion: altered mental status or fatigue indicates impending respiratory failure 1, 3

Treatment Algorithm by Severity

Mild Croup (Stridor only with agitation, no retractions)

• Administer oral dexamethasone 0.15–0.6 mg/kg as a single dose 4, 5, 2
• Supportive care with humidified air (maintain >50% relative humidity) 4
• Observe for 3–4 hours for clinical improvement 5
• Discharge home if no respiratory distress develops and family has reliable access to follow-up 5, 3

Moderate-to-Severe Croup (Stridor at rest, retractions, respiratory distress)

• Administer oral dexamethasone 0.6 mg/kg immediately (higher dose within the range is preferred for severe disease) 4, 2
• Add nebulized epinephrine 0.5 mL/kg of 1:1000 solution (racemic or L-epinephrine are equally effective) 1, 5, 2
• Provide supplemental oxygen if oxygen saturation <92% 1
• Observe for at least 2–3 hours after epinephrine administration to monitor for rebound airway obstruction 4, 5
• Repeat epinephrine every 20–30 minutes if needed while awaiting steroid effect (onset ~6 hours) 4

Alternative if Oral Dexamethasone Cannot Be Tolerated

• Nebulized budesonide 500 µg (or 2 mg) can be used if the infant cannot tolerate oral medication 1, 2
• Note: Nebulized budesonide may reduce symptoms in the first 2 hours but has limited long-term outcome data 1

Hospitalization Criteria

Admit to hospital if any of the following are present:

• Stridor at rest persisting after treatment 3
• Persistent increased work of breathing or retractions 3
• Oxygen saturation <92% on room air 1
• Signs of exhaustion, agitation, or altered consciousness 1, 3
• Inability to tolerate oral intake or maintain hydration 1
• Need for repeated doses of nebulized epinephrine (suggests severe disease) 1, 4
• Age <6 months (this 5-month-old is at higher risk for rapid deterioration) 1

Critical Pitfalls to Avoid

• Do not use nebulized epinephrine in children who will be discharged shortly – the effect is short-lived (1–2 hours) and rebound obstruction can occur 1, 4
• Do not use lower doses of dexamethasone (<0.15 mg/kg) – these have proven ineffective 4
• Do not rely on humidified air or cool mist alone – these lack evidence of efficacy and should not replace corticosteroids 2
• Do not assume viral croup without excluding epiglottitis or foreign body aspiration – these require different urgent management 3
• Do not delay transfer to intensive care if the child develops cyanosis, silent chest, poor respiratory effort, or exhaustion – these are life-threatening features requiring immediate airway intervention 1

Discharge Planning (If Outpatient Management Appropriate)

Discharge is safe after 3 hours of observation if:

• No stridor at rest 5, 3
• No respiratory distress or retractions 5, 3
• Reliable access to follow-up and emergency care 5, 3
• Family understands return precautions: worsening stridor, inability to feed, lethargy, cyanosis 3

Special Considerations for a 5-Month-Old

At 5 months of age, this infant is at the younger end of the typical croup age range (6 months to 6 years) and warrants closer observation 4, 5. Infants <6 months have smaller airways and are at higher risk for rapid deterioration and hospitalization 1. A lower threshold for admission should be maintained, and any uncertainty about severity should favor inpatient observation 1, 3.