- Respiratory distress at rest: stridor, tachypnea, retractions, nasal flaring – may require epinephrine and hospitalization
- Hypoxia (SpO₂ <92%): suggests severe airway obstruction or secondary process (pneumonia)
- Bacterial tracheitis: high fever, toxic appearance, poor response to standard croup therapy – requires antibiotics and possibly intubation
Croup (Laryngotracheobronchitis)
Must-Not-Miss / Red Flags
Patient Explanation
“Your child has a viral infection that makes their throat swell, causing a barking cough and noisy breathing. Cool air and medicine will help them breathe easier.”
Board Fact
“The steeple sign (subglottic narrowing) on a frontal neck X‑ray is classic for croup, but diagnosis is clinical; radiographs are not routinely needed.”
ICD-10
J05.0
Definition & Core Concept
Croup is an acute viral infection of the upper airway (larynx and trachea) in young children, characterized by a barking cough, stridor, and hoarseness, most commonly caused by parainfluenza virus type 1.
Epidemiology & Risk Factors
- Most common cause of stridor in children 6 months to 3 years
- Seasonal: peak in fall and early winter
- Parainfluenza virus type 1 causes 50‑75% of cases
Clinical Vignette
A 2‑year‑old boy awakens at midnight with a harsh, barking cough and noisy breathing. He has inspiratory stridor at rest and mild retractions. His parents took him outside in the cool night air, which provided temporary improvement. In the ED, he receives dexamethasone and one dose of racemic epinephrine with complete resolution of stridor.
Pearls & Pitfalls
- Croup is primarily a clinical diagnosis – neck X‑rays are not needed in typical cases and may cause unnecessary anxiety and radiation.
- Racemic epinephrine provides rapid relief but does not alter the disease course; observe for at least 2‑3 hours after administration as rebound stridor can occur.
Discharge & Follow-Up
Discharge if no stridor at rest after observation. Educate parents on signs of worsening: increased work of breathing, drooling, inability to swallow, pallor. Keep follow‑up with pediatrician in 1‑2 days.
Literature & Guidelines
Canadian Paediatric Society 2024 Position Statement on Croup. PMID: 38780201.