Severity assessment of croup

The severity of croup can be categorised as:

• mild—no stridor at rest, mild chest wall retractions and normal respiratory rate
• moderate—stridor at rest, moderate chest wall retractions, use of accessory respiratory muscles, increased respiratory rate and tachycardia
• severe—persisting stridor at rest, increasing fatigue, markedly increased or decreased respiratory rate, markedly decreased air entry and marked tachycardia.

Important points in the early assessment of a child with suspected croup are:

• Loudness of stridor is not a good guide to the severity of obstruction.
• Avoid examination procedures that create anxiety (eg throat examination, physically separating the child from the parent or carer) because this exacerbates croup.
• Blood tests, oxygen therapy and nasopharyngeal aspirate are rarely indicated.

Restlessness, decreased level of consciousness, hypotonia, cyanosis and pallor are signs of life-threatening airway obstruction; arrange immediate transport to hospital for emergency-department treatment. Life-threatening croup requires immediate senior, intensive care or anaesthetics team involvement.

The following children may be at risk of severe croup and require close observation:

• young children (eg aged less than 6 months)
• children with pre-existing narrowing of the upper airways (eg craniofacial abnormalities, Down syndrome)
• children with a history of previous severe croup
• children with a history of unplanned representation to hospital emergency department within 24 hours of first croup presentation.