creation date: 2026-09-07 19:04
tags: Pathologies
Croup
Background
Definitions
Croup, also known as acute laryngotracheobronchitis, is an inflammation fo the upper airway that occurs with young children.
Etiology
The most common cause is:
- Parainfluenza virus type 1 and 3
Other viruses include:
- RSV
- COVID-19
- Influenza A and B
- Adenovirus
Pathogenesis
Viral infection causes inflammation of the upper airway. This results in edema formation and infiltration of inflammatory cells that narrows the subglottic airway.
Risk Factors
Individuals at risk are:
- Children aged 6 months-3 years (peak at 2 years)
- Boys > girls
- Fall/winter months
Clinical Presentation
Signs & Symptoms
Prodrome (1-2 days):
- Nonspecific upper respiratory tract infection symptoms
- Sore throat
- Rhinitis
- Low grade fever
Classic symptoms:
- Barky cough
- Inspiratory stridor
- Hoarseness
- Respiratory distress (increased work of breathing)
Symptoms typically last 3-7 days.
History & Physical Exam
Diagnosis
Criteria
Diagnosis is made clinically.
Mild: no stridor or substantial wall indrawing at rest
Moderate: stridor or chest wall indrawing at rest without agitation
Severe: stridor and indrawing of sternum associated with agitation or lethargy
Work-up
Differential
Children who present with croup <6 months of age or have unusual symptoms (recurrent, prolonged, unusually severe) must have other causes of airway narrowing ruled out:
- Bacterial tracheitis (high fever, toxic appearance, poor response to nebulized epi)
- Retropharyngeal, parapharyngeal, peritonsillar abscesses (high fever, neck pain, sore throat, dysphagia; followed by torticollis, drooling, respiratory distress, stridor)
- Epiglottitis (lack barky cough, sudden onset of high fever, dysphagia, drooling, toxic appearance, sitting forward)
- Aspiration or ingestion of foreign body (croupy cough, choking episode, wheeze, hoarseness, biphasic stridor, dyspnea, decreased air entry)
- Acute allergic reaction (rapid onset dysphagia, wheezing, stridor, other anaphylaxis signs)
Red Flags / Complications
Management
Mild Croup
Mild coup is treated with:
- Dexamethasone 0.6 mg/kg PO
- Education and discharge
Moderate Croup
Moderate treated with:
- Dexamethasone 0.6 mg/kg PO
- Observation for improvement
Consider hospital admission if no or minimal improvement by 4 hours.
Severe Croup
Severe cases are treated with:
- Blow-by oxygen if needed (indicated for cyanosis/hypoxia)
- Nebulized epinephrine (5 mL of 1 mg/mL)
- Dexamethasone 0.6 mg/kg PO, repeat once prn
Discharge if:
- Good response to epinephrine
- No recurrence of chest wall indrawing and stridor at rest, 2 hours later
Consider hospital admission if:
- Good response to epinephrine
- Continued moderate respiratory distress, stridor at rest, chest wall indrawing after ≥4 hours following steroid
If the response to epinephrine is poor:
- Consult pediatric ICU
- Repeat nebulized epinephrine q1h prn