What is the first line of treatment for a 2-year-old patient presenting with a barking cough, likely diagnosed with croup?

First-Line Treatment for Barky Cough in a 2-Year-Old (Croup)

Administer a single dose of oral dexamethasone 0.15-0.60 mg/kg (maximum 10 mg) immediately to all children with croup, regardless of severity. 1, 2

Immediate Assessment

Evaluate the child's severity by checking for:

• Stridor at rest (indicates moderate-to-severe disease requiring additional treatment) 1
• Respiratory distress signs: use of accessory muscles, nasal flaring, retractions 1
• Oxygen saturation (hypoxemia <94% indicates need for oxygen therapy) 1
• Ability to speak/cry normally and overall level of agitation 1

Treatment Algorithm

All Cases (Mild, Moderate, Severe):

• Give oral dexamethasone 0.15-0.60 mg/kg as a single dose (most studies use 0.6 mg/kg, though 0.15 mg/kg appears equally effective) 1, 2, 3
• If oral route unavailable, use intramuscular dexamethasone at same dose 4
• Alternative: prednisolone 1-2 mg/kg (maximum 40 mg) if dexamethasone unavailable 1

Moderate-to-Severe Cases (Stridor at Rest or Respiratory Distress):

• Add nebulized epinephrine 0.5 mL/kg of 1:1000 solution (or 0.5 mL of 2.25% racemic epinephrine diluted in 2.5 mL saline) 1, 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
• Administer oxygen to maintain saturation ≥94% 1

Hospitalization Criteria

Admit if any of the following:

• Three or more doses of nebulized epinephrine required 1
• Oxygen saturation <92% 1
• Age <18 months with moderate-to-severe symptoms 1
• Respiratory rate >70 breaths/min 1
• Signs of exhaustion, cyanosis, or silent chest 1

Recent evidence shows limiting admission until 3 doses of epinephrine are needed reduces hospitalization by 37% without increasing adverse outcomes 1

What NOT to Do

• Never discharge within 2 hours of nebulized epinephrine due to rebound risk 1
• Do not use humidified/mist therapy - no proven benefit 1, 2, 5
• Avoid chest radiographs unless considering alternative diagnoses 1
• Do not perform blind finger sweeps if foreign body suspected 1
• Avoid OTC cough/cold medications in children under 2 years (ineffective and potentially toxic) 6

Differential Diagnoses to Consider

If the child fails to respond to standard treatment or has atypical features, consider:

• Bacterial tracheitis (toxic appearance, high fever) 1, 2
• Foreign body aspiration (sudden onset, unilateral findings, no prodrome) 1, 2
• Epiglottitis (rare post-Hib vaccine, but life-threatening) 2
• Retropharyngeal or peritonsillar abscess 2

Discharge Instructions

If discharging home after observation:

• Ensure family can reliably monitor and return if worsening 1
• Symptoms typically resolve within 2 days, though cough may persist 2
• Return immediately for: increased work of breathing, inability to drink, cyanosis, or worsening stridor 6
• Follow up with primary care if not improving after 48 hours 6

Common Pitfalls

The most critical error is discharging too soon after nebulized epinephrine - the 2-hour observation period is mandatory to detect rebound symptoms 1. Another common mistake is using nebulized epinephrine in outpatient settings where immediate return isn't feasible 1. Finally, avoid over-reliance on radiographs - croup is a clinical diagnosis and imaging is rarely helpful 1, 2.