Spasmodic Croup

Spasmodic croup is sudden-onset recurrent barking cough and stridor, usually at night, without fever or a significant viral prodrome, thought to involve allergy, reflux or airway hyper-reactivity as well as viral triggers.

• It affects children aged 1 to 3 years and often recurs, with a family tendency to atopy.
• Episodes resolve within hours, and the child is usually well in the morning.
• It is milder than viral croup and rarely needs hospital treatment.
• Associated factors include atopy, gastro-oesophageal reflux and viral infections.

The child wakes suddenly at night.

• Abrupt barking cough, hoarseness and inspiratory stridor, typically in the middle of the night.
• Little or no fever and minimal coryza beforehand.
• Child is anxious and distressed.
• Improves within 30 minutes to a few hours, often sooner with cool night air.
• Recurrent episodes on successive nights are typical.
• Normal during the day.
• Differential diagnosis: viral croup, foreign body, reflux laryngitis, laryngomalacia, vocal cord dysfunction, subglottic stenosis, allergy, asthma and bacterial tracheitis.
• Complications: respiratory distress (uncommon), parental anxiety, and recurrence.

Diagnosis is clinical, by history.

• Typical history of night-time onset, absence of fever, rapid resolution.
• Examination between episodes is normal.
• Investigate for atopy, reflux, or structural airway problem if episodes are frequent (more than three) or severe, or if stridor persists between episodes.
• Flexible laryngoscopy or airway endoscopy for recurrent or atypical episodes.
• Oxygen saturation should be measured during an acute episode.

Most episodes need only calming measures.

• Supportive: calm the child, take outdoors into cool night air or a steamy bathroom (benefit unproven), keep upright, and offer fluids.
• Pharmacological: dexamethasone 0.15 to 0.6 mg/kg orally once (maximum 10 mg) if the episode is moderate or does not settle. Nebulised adrenaline 1:1000, 0.5 mL/kg up to 5 mL for severe stridor at rest.
• For recurrent episodes linked to reflux: omeprazole 1 mg/kg once daily for 4 to 8 weeks. For atopy: cetirizine 2.5 mg twice daily (1 to 2 years) or 5 mg once daily (2 to 5 years).
• Procedures: airway endoscopy for recurrent severe episodes with persisting symptoms.
• Special groups: infants under 1 year with stridor need specialist assessment.
• Red flags: persistent stridor between episodes, fever, drooling, cyanosis, poor feeding, and failure to improve.
• Follow-up: reassure parents; most children outgrow the episodes by 5 to 6 years. Refer to ENT if recurrent.