Croup is a viral illness with inflammation of the upper airway. It is also known as acute viral laryngo-tracheo-bronchitis.

Key points

  • Hypoxia is a late sign & indicates severe croup
  • Minimal handling is key principle of management. Avoid distressing the child
  • Investigations are usually not necessary
  • If the child requires two or more adrenaline nebulisers, he/she should be admitted for an extended period of observation
  • Beware children <6 months with stridor
  • Croup is less common in children less than 6 months of age. All children <6 months of age with new onset stridor should have a review by a senior clinician prior to discharge with strong consideration for an emergent ENT review, especially for children <3 months of age

Assessing Severity

Signs of life threatening croup:

  • Hypoxia
  • Cyanosis
  • ↓ alertness

Signs of severe croup:

  • Moderate/severe chest wall retractions
  • Markedly decreased air entry


  • Viral prodrome (1-2 days corryzal symptoms)
  • Harsh barking cough
  • Hoarse voice and stridor
  • Fever <38°
  • Stridor worse on crying and worse at night


  • Tachypnoea
  • Tachycardia
  • Sternal recession
  • Tracheal tug
  • Cyanosis on crying


  • Continuous harsh sound
  • Caused by obstruction in the larynx and trachea
  • Predominantly inspiratory
  • Expiratory component may be present - ? subglottic lesion
  • Higher incidence in children than in adults (anatomical differences)

Differential diagnosis


  • Drooling and pain on swallow
  • Unwell appearance
  • Absence of barking cough
  • Muffled hot potato voice
  • Tripod or sniffing position
  • Anxiety out of proportion to degree of resp. distress

Bacterial tracheitis

  • Often school age
  • Associated pain on swallowing
  • Soft stridor 2-7 days after onset of URTI symptoms
  • Often unwell looking
  • Significant tracheal tenderness on palpation
  • Reluctant to cough because of pain

Foreign body

  • Often < 3 years of age
  • Abrupt onset @ daytime (croup @ night)
  • Dysphagia, drooling
  • Dysphonia depending on location of foreign body
  • Minimal response to adrenaline nebuliser


  • Deep space neck infection
  • Angioneurotic oedema
  • Anaphylaxis

If <6 months of age consider:

  • Laryngomalacia
  • Subglottic haemangioma
  • Vascular ring
  • Laryngotracheomalacia
  • Vocal cord abnormality
  • Other congenital airway anomaly

Croup management

Severe croup

  • Manage in Resusc. room & record case in the log please
  • Minimal handling, place on parents lap if felt to be appropriate by clinical staff
  • Avoid distressing the child. Allow the child to find a position of comfort
  • Adrenaline nebuliser 5mg (5mls of 1:1000). Repeat if necessary
  • Dexamethasone 0.6mg/kg PO. This may be deferred 10-15 minutes while adrenaline nebuliser is being completed
  • Consider IM dexamethasone 0.6mg/kg if PO route is not feasible eg vomiting, patient refusal or obtunded
  • An IV line should be deferred
  • Supplemental O2 if hypoxic. Consider “blow-by” O2:
    • Hypoxia is rare in croup and indicates severe airways obstruction
  • Any of hypoxia/altered mental state/paradoxical breathing / poor response to adrenaline nebuliser contact paediatric anaesthesia to arrange emergent gaseous induction for intubation. This is a life threatening situation

Mild/moderate croup

  • Minimal handling, place on parents lap if felt to be appropriate by clinical staff
  • Avoid distressing the child. Allow the child to find a position of comfort
  • PO dexamethasone 0.15mg/kg
  • No investigations required unless diagnosis is doubt



Indicators of increasing severity:

  • Increasing respiratory rate
  • Increasing stridor
  • ↓ air entry on auscultation
  • Cyanosis at rest with O2 sats. <95% in air
  • Δ level of consciousness

Can go home when:

  • No stridor at rest
  • No oxygen requirement
  • No increased work of breathing
  • Parents confident about ongoing management at home and know when to return
  • Must be observed for >4 hours after adrenaline nebuliser

At risk:

  • Children with pre-existing narrowing of the upper airways (eg. subglottic stenosis congenital or 2° to neonatal ventilation) or
  • Children with Down Syndrome

At risk are prone to more severe croup and admission should be considered even with mild symptoms.

Content by Dr Rory O' Brien 29/03/2019. Last review Dr Karol O'Donovan 10/02/23.