Croup

Definition

• Viral inflammation of the larynx, trachea, and bronchi, typically affecting children aged 6 months to 3 years

• Characterised by a barking cough, inspiratory stridor, and varying degrees of respiratory distress

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Common Pathogens

• Parainfluenza virus type 1 is most common

• Other causes include RSV, influenza A/B, and adenovirus

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Severity

• Mild

  • Barking cough without stridor at rest

  • Minimal work of breathing

• Moderate

  • Frequent barking cough

  • Stridor at rest with mild to moderate work of breathing

  • No significant agitation or drowsiness

• Severe

  • Marked work of breathing, accessory muscle use, possible inspiratory and expiratory stridor

  • Agitation or altered level of consciousness

  • Tachypnoea or occasional bradypnoea

• Life-Threatening

  • Cyanosis, significant lethargy, exhaustion

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Treatment

• General Measures

  • Minimise distress and handling

  • Allow the child to sit upright or choose a comfortable position

• Mild to Moderate Croup

  • Oral prednisolone 1 mg/kg or dexamethasone 0.15 mg/kg (maximum 10 mg)

  • Observe for recurrence of stridor at rest, which may warrant further intervention

• Severe Croup

  • Nebulised adrenaline 0.5 mL/kg of 1:1000 (maximum 5 mL)

  • Dexamethasone 0.6 mg/kg by any route (maximum 12 mg)

  • Monitor for at least 4 hours to watch for rebound symptoms

• Additional Points

  • Nebulised budesonide can be an alternative if oral or IV steroids are not tolerated

  • Oxygen is rarely needed unless severe hypoxaemia is present

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Notes

• Hypoxia is a late and ominous sign

• IV access should be avoided unless absolutely necessary

• Most children improve within 48 hours, though residual cough can persist

• Consider hospital admission if there is persistent stridor at rest, severe work of breathing, or poor oral intake

• Advise parents to seek urgent care if breathing worsens or stridor returns at rest at home