Overview

Croup (Laryngotracheobronchitis)

Quick Reference

Critical Alerts

Stridor at rest indicates moderate-severe disease: Requires treatment
Dexamethasone is first-line for ALL: Even mild croup benefits
Nebulized epinephrine for moderate-severe: Works within minutes
Observe after epinephrine: Rebounds in 2-3 hours; observe 3-4 hours
Rarely progresses to obstruction: But can be life-threatening
Consider epiglottitis if toxic-appearing: Rare but serious

Key Diagnostics

Finding	Significance
Barky "seal-like" cough	Hallmark of croup
Inspiratory stridor	Subglottic narrowing
Hoarse voice	Laryngeal involvement
Low-grade fever	Common
Preceding URI symptoms	Typical prodrome

Emergency Treatments (Pediatric Dosing)

Intervention	Dose	Notes
Dexamethasone	0.15-0.6 mg/kg PO/IM/IV (max 10-16 mg)	Single dose; ALL croup patients
Nebulized epinephrine (racemic)	0.5 mL of 2.25% + 2.5 mL NS	For moderate-severe; observe 3-4h
Nebulized epinephrine (L-epi)	0.5 mg/kg (max 5 mg) of 1:1000	Alternative to racemic
Heliox	70:30 or 80:20 HeO2	Severe, awaiting response to steroids
Humidified oxygen	PRN	If hypoxic; mist therapy unproven

Definition

Overview

Croup (acute laryngotracheobronchitis) is a common viral respiratory illness causing inflammation of the upper airway, primarily affecting the subglottic region. It is characterized by the classic triad of barky (seal-like) cough, inspiratory stridor, and hoarseness. Croup is usually self-limited but can cause significant upper airway obstruction in severe cases.

Classification

Westley Croup Score:

Factor	Score
Stridor	0 = None, 1 = At rest with stethoscope, 2 = At rest without stethoscope
Retractions	0 = None, 1 = Mild, 2 = Moderate, 3 = Severe
Air entry	0 = Normal, 1 = Decreased, 2 = Markedly decreased
Cyanosis	0 = None, 4 = Cyanosis with agitation, 5 = Cyanosis at rest
Level of consciousness	0 = Normal, 5 = Disoriented

Severity	Westley Score	Clinical Features
Mild	0-2	Barky cough, no stridor at rest, no retractions
Moderate	3-5	Stridor at rest, mild-moderate retractions
Severe	6-11	Marked stridor, significant retractions, decreased air entry
Impending failure	≥12	Lethargy, cyanosis, minimal air entry

Types of Croup

Type	Features
Viral croup (most common)	URI prodrome, low-grade fever, gradual onset
Spasmodic croup	Sudden onset (often at night), no fever, recurrent
Bacterial tracheitis	Toxic-appearing, high fever, poor response to croup treatment

Epidemiology

Peak age: 6 months to 3 years (rare <6 months or >6 years)
Peak incidence: 2nd year of life
Seasonality: Fall and early winter (parainfluenza)
Incidence: 5-6% of children <6 years
Hospitalization rate: 1-5% of croup cases
Intubation rate: <1% of hospitalized cases

Etiology

Viral Causes:

Virus	Frequency
Parainfluenza (types 1-3)	75% (type 1 most common)
RSV	5-10%
Influenza A/B	5-10%
Adenovirus	5%
Rhinovirus	5%
Coronavirus	2-5%
Human metapneumovirus	2-5%

Pathophysiology

Mechanism of Croup

Viral infection: Upper respiratory mucosa → descends to larynx/trachea
Inflammation: Edema of larynx, trachea, bronchi
Subglottic narrowing: Narrowest part of pediatric airway
Turbulent airflow: Stridor (inspiratory > expiratory)
Increased work of breathing: Retractions, accessory muscle use
Severe obstruction: Hypoxia, hypercapnia, respiratory failure

Why Children Are More Affected

Subglottic airway is narrowest anatomic point
1 mm of edema in infant reduces cross-sectional area by ~50%
Adult airway is wider, more rigid

Stridor Physiology

Inspiratory stridor: Extrathoracic obstruction (larynx/trachea) collapses on inspiration
Expiratory stridor: Intrathoracic (bronchi) collapses on expiration
Biphasic stridor: Fixed lesion or severe obstruction

Clinical Presentation

Classic Presentation

Prodrome (1-2 days):

Acute Phase (Days 2-4):

History

Key Questions:

Physical Examination

General:

Finding	Interpretation
Alert, playful	Mild disease
Uncomfortable, anxious	Moderate disease
Exhausted, lethargic	Severe, impending failure

Vital Signs:

Finding	Significance
Low-grade fever	Typical for viral croup
High fever (>9°C)	Consider bacterial tracheitis, epiglottitis
Tachypnea	Increased work of breathing
Hypoxia	Severe (late finding)

Respiratory Examination:

Finding	Severity
Barky cough only	Mild
Stridor with agitation	Mild-moderate
Stridor at rest	Moderate-severe
Retractions (intercostal, subcostal)	Moderate-severe
Decreased air entry	Severe
Cyanosis	Impending failure

Rhinorrhea, congestion

Common presentation.

Low-grade fever

Common presentation.

Mild cough

Common presentation.

Red Flags

Concerning for Severe Disease

Finding	Concern	Action
Stridor at rest	Moderate-severe croup	Dexamethasone + nebulized epinephrine
Chest wall retractions at rest	Significant obstruction	Aggressive treatment
Cyanosis	Severe hypoxemia	O2, prepare for airway
Altered mental status	Hypoxemia, hypercapnia	Prepare for intubation
Drooling, toxic appearance	Epiglottitis/bacterial tracheitis	Airway emergency
High fever + toxic	Bacterial tracheitis	Antibiotics, ICU
Poor response to treatment	Consider alternative Dx	Reassess, ENT

Mimics (Must Not Miss)

Diagnosis	Features
Epiglottitis	Toxic, drooling, tripoding, high fever, no cough
Bacterial tracheitis	Toxic, high fever, poor response to croup Rx
Foreign body aspiration	Sudden onset, no prodrome, unilateral
Retropharyngeal abscess	Drooling, neck stiffness, neck swelling
Anaphylaxis	Urticaria, angioedema, exposure history
Angioedema	Swelling without urticaria, medication related

Differential Diagnosis

Other Causes of Stridor in Children

Diagnosis	Key Features
Epiglottitis	4 D's: Drooling, dysphagia, dysphonia, distress
Bacterial tracheitis	Follows viral croup, toxic, high fever
Foreign body aspiration	Sudden, choking episode, unilateral findings
Retropharyngeal abscess	Neck stiffness, drooling, uvula deviated
Peritonsillar abscess	Older child, trismus, muffled voice
Angioedema	Medication-related swelling, no fever
Laryngomalacia	Chronic stridor since birth, improves with prone
Subglottic stenosis	History of intubation
Vascular ring	Chronic stridor, feeding difficulties

Diagnostic Approach

Clinical Diagnosis

Croup is diagnosed CLINICALLY
No routine labs or imaging required
Characteristic presentation is sufficient

When to Consider Imaging

Neck/Soft Tissue X-Ray:

Finding	Diagnosis
"Steeple sign"	Croup (subglottic narrowing)
"Thumbprint sign"	Epiglottitis (swollen epiglottis)
Widened prevertebral space	Retropharyngeal abscess
Subglottic narrowing	Croup; may be normal

Indications for X-Ray:

Atypical presentation
No response to treatment
Concern for alternative diagnosis (epiglottitis, foreign body)
Recurrent or chronic stridor

CXR: Not routinely indicated; consider if pneumonia suspected

Laboratory Studies

Not routinely required
Consider if septic-appearing or concern for bacterial superinfection

Treatment

Principles of Management

Keep child calm: Agitation worsens stridor
Dexamethasone for ALL: Even mild croup
Nebulized epinephrine for moderate-severe: Works within minutes
Observe after epinephrine: Rebound possible
Minimize interventions: Avoid distressing the child

Keeping Child Calm

Allow parent to hold child
Position of comfort
Minimize invasive procedures
Calm environment

Corticosteroids (First-Line for ALL)

Dexamethasone:

Route	Dose	Notes
PO (preferred)	0.15-0.6 mg/kg (max 10-16 mg)	Single dose
IM	Same dose	If vomiting or unable to take PO
IV	Same dose	Rarely needed

Key Points:

Single dose is sufficient
Reduces ED revisits, hospitalization, need for intubation
Onset: 1-2 hours; peak: 6 hours
Works for all severities (including mild)

Alternatives (If dexamethasone unavailable):

Drug	Dose
Prednisolone	1-2 mg/kg PO
Budesonide nebulized	2 mg (less effective than dexamethasone)

Nebulized Epinephrine (Moderate-Severe)

Indications:

Stridor at rest
Significant retractions
Respiratory distress

Dosing:

Formulation	Dose
Racemic epinephrine 2.25%	0.5 mL in 2.5-3 mL NS
L-epinephrine 1:1000	0.5 mg/kg (max 5 mg = 5 mL)

Administration: Via nebulizer with O2 or air

Onset: 10-30 minutes

Duration: 2 hours (rebound possible)

Observation: Minimum 3-4 hours post-epinephrine before discharge

Observation After Epinephrine

Why?:

Effect wears off in 2 hours
Stridor may return ("rebound")
Must observe for recurrence

Can Discharge If:

≥3-4 hours since last epinephrine
Received dexamethasone
No stridor at rest
No significant retractions
Reliable caregivers
Able to return quickly

Oxygen

Give if hypoxic (SpO2 <90%)
Blow-by (avoid face mask distress) if needed
HFNC or hood O2 if significant requirement

Heliox

70:30 or 80:20 Helium:Oxygen mixture
Reduces airway turbulence
Bridge while waiting for steroids to work
Rarely needed

Humidified Air/Mist Therapy

No proven benefit in RCTs
Still commonly used
May provide psychological comfort to parents
Night air (cool, humid) anecdotally helpful

Intubation (Rare)

Indications:

Impending respiratory failure
Severe hypoxemia despite treatment
Altered mental status

Approach:

Experienced provider
Smaller ETT (0.5-1 mm smaller than age-appropriate)
Expect subglottic edema
Prepare surgical airway as backup (cricothyrotomy/tracheostomy)

Disposition

Discharge Criteria

Mild croup (no stridor at rest after treatment)
≥3-4 hours post-epinephrine (if given)
Received dexamethasone
Tolerating fluids
Normal oxygenation
Reliable caregivers educated on warning signs
Able to return if worsening

Admission Criteria

Persistent stridor at rest despite treatment
Ongoing respiratory distress
Repeated epinephrine doses needed
Hypoxia
Toxic appearance
High-risk patient (underlying airway disease)
Social concerns

ICU Admission Criteria

Severe croup with significant resp distress
Need for continuous nebulized epinephrine
Intubated patient
Impending respiratory failure

Follow-Up

Situation	Follow-Up
Discharged, improving	PCP in 24-48 hours if not improved
Recurrent croup (> episodes)	ENT referral for airway evaluation

Patient Education

Condition Explanation (For Parents)

"Croup is a viral infection that causes swelling in the voice box and windpipe."
"The classic barky cough and stridor are caused by the narrowed airway."
"The medicine we gave will reduce the swelling."
"Symptoms are typically worse at night and should improve over 2-3 days."

Home Care

Keep child calm; crying worsens stridor
Cool mist (humidifier) may help—no proven benefit but safe
Cool night air anecdotally helps some children
Encourage fluids
Acetaminophen/ibuprofen for fever or discomfort
Monitor breathing closely

Warning Signs (Return Immediately)

Stridor at rest or worsening stridor
Increased work of breathing (retractions)
Drooling or inability to swallow
High fever developing (>39.5°C)
Bluish color around lips
Very sleepy or difficult to arouse
Not improving after 3 days

Expected Course

Worst on nights 1-2
Barky cough may persist 3-7 days
Usually fully resolves within 1 week

Special Populations

Recurrent/Spasmodic Croup

Sudden onset (often at night)
No or minimal viral prodrome
No or low fever
Responds to steroids/epinephrine
May be related to hyperreactive airway
Consider ENT referral for airway evaluation (subglottic stenosis)

Age <6 Months

Atypical age for croup
Consider congenital airway abnormality
Lower threshold for investigation and admission

History of Intubation

Risk of subglottic stenosis
May present with "croup-like" symptoms
ENT/Pulmonology evaluation if recurrent

Immunocompromised

More severe, prolonged disease
Consider bacterial superinfection
Lower threshold for admission

Quality Metrics

Performance Indicators

Metric	Target	Rationale
Dexamethasone given	>5%	Reduces morbidity, ED return
Observation ≥3h post-epinephrine	100%	Prevent rebound
Caregiver education on warning signs	100%	Safety
Avoid routine labs/imaging	>0%	Reduce unnecessary testing
Avoid antibiotics	>5%	Croup is viral

Documentation Requirements

Severity assessment (Westley score or narrative)
Response to treatment
Duration of observation (if epinephrine given)
Discharge instructions
Follow-up plan

Key Clinical Pearls

Diagnostic Pearls

Barky cough = croup: Almost pathognomonic
Stridor at rest = moderate-severe: Needs treatment
High fever + toxic = not simple croup: Think bacterial tracheitis or epiglottitis
"Steeple sign" on X-ray: Not required, but confirmatory
Recurrent croup may have underlying cause: Consider ENT referral
Rare in infants <6 months: Think congenital airway

Treatment Pearls

Dexamethasone for ALL severities: Even mild croup benefits
Single dose is sufficient: No need for multi-day steroids
Epinephrine works fast: But wears off in 2 hours
Observe after epinephrine: Minimum 3-4 hours
Keep child calm: Agitation worsens obstruction
Mist therapy unproven: But harmless if it helps

Disposition Pearls

Discharge most croup: With steroids on board
Don't discharge within 3-4 hours of epinephrine: Rebound risk
Recurrent croup needs follow-up: Evaluate for underlying cause
Parent education is essential: Know when to return

References

Bjornson CL, Johnson DW. Croup in children. CMAJ. 2013;185(15):1317-1323.
Gates A, et al. Glucocorticoids for croup in children. Cochrane Database Syst Rev. 2018;(8):CD001955.
Bjornson C, et al. Nebulized epinephrine for croup in children. Cochrane Database Syst Rev. 2013;(10):CD006619.
Russell KF, et al. Glucocorticoids for croup. Cochrane Database Syst Rev. 2011;(1):CD001955.
Petrocheilou A, et al. Viral Croup: Diagnosis and a Treatment Algorithm. Pediatr Pulmonol. 2014;49(5):421-429.
Dobrovoljac M, et al. Dexamethasone in croup: single-dose vs. 3 doses. J Pediatr Emerg Care. 2014;30(12):826-829.
Westley CR, et al. Nebulized racemic epinephrine by IPPB for the treatment of croup. Am J Dis Child. 1978;132(5):484-487.
UpToDate. Croup: Clinical features, evaluation, and diagnosis. 2024.

Finding

Significance

Barky "seal-like" cough

Hallmark of croup

Inspiratory stridor

Subglottic narrowing

Hoarse voice

Laryngeal involvement

Low-grade fever

Common

Preceding URI symptoms

Typical prodrome

Intervention

Dose

Notes

Dexamethasone

0.15-0.6 mg/kg PO/IM/IV (max 10-16 mg)

Single dose; ALL croup patients

Nebulized epinephrine (racemic)

0.5 mL of 2.25% + 2.5 mL NS

For moderate-severe; observe 3-4h

Nebulized epinephrine (L-epi)

0.5 mg/kg (max 5 mg) of 1:1000

Alternative to racemic

Heliox

70:30 or 80:20 HeO2

Severe, awaiting response to steroids

Humidified oxygen

PRN

If hypoxic; mist therapy unproven

Factor

Score

Stridor

0 = None, 1 = At rest with stethoscope, 2 = At rest without stethoscope

Retractions

0 = None, 1 = Mild, 2 = Moderate, 3 = Severe

Air entry

0 = Normal, 1 = Decreased, 2 = Markedly decreased

Cyanosis

0 = None, 4 = Cyanosis with agitation, 5 = Cyanosis at rest

Level of consciousness

0 = Normal, 5 = Disoriented

Severity

Westley Score

Clinical Features

Mild

0-2

Barky cough, no stridor at rest, no retractions

Moderate

3-5

Stridor at rest, mild-moderate retractions

Severe

6-11

Marked stridor, significant retractions, decreased air entry

Impending failure

≥12

Lethargy, cyanosis, minimal air entry

Type

Features

Viral croup (most common)

URI prodrome, low-grade fever, gradual onset

Spasmodic croup

Sudden onset (often at night), no fever, recurrent

Bacterial tracheitis

Toxic-appearing, high fever, poor response to croup treatment

Virus

Frequency

Parainfluenza (types 1-3)

75% (type 1 most common)

RSV

5-10%

Influenza A/B

5-10%

Adenovirus

Rhinovirus

Coronavirus

2-5%

Human metapneumovirus

2-5%

Finding

Interpretation

Alert, playful

Mild disease

Uncomfortable, anxious

Moderate disease

Exhausted, lethargic

Severe, impending failure

Finding

Significance

Low-grade fever

Typical for viral croup

High fever (>9°C)

Consider bacterial tracheitis, epiglottitis

Tachypnea

Increased work of breathing

Hypoxia

Severe (late finding)

Finding

Severity

Barky cough only

Mild

Stridor with agitation

Mild-moderate

Stridor at rest

Moderate-severe

Retractions (intercostal, subcostal)

Moderate-severe

Decreased air entry

Severe

Cyanosis

Impending failure

Finding

Concern

Action

Stridor at rest

Moderate-severe croup

Dexamethasone + nebulized epinephrine

Chest wall retractions at rest

Significant obstruction

Aggressive treatment

Cyanosis

Severe hypoxemia

O2, prepare for airway

Altered mental status

Hypoxemia, hypercapnia

Prepare for intubation

Drooling, toxic appearance

Epiglottitis/bacterial tracheitis

Airway emergency

High fever + toxic

Bacterial tracheitis

Antibiotics, ICU

Poor response to treatment

Consider alternative Dx

Reassess, ENT

Diagnosis

Features

Epiglottitis

Toxic, drooling, tripoding, high fever, no cough

Bacterial tracheitis

Toxic, high fever, poor response to croup Rx

Foreign body aspiration

Sudden onset, no prodrome, unilateral

Retropharyngeal abscess

Drooling, neck stiffness, neck swelling

Anaphylaxis

Urticaria, angioedema, exposure history

Angioedema

Swelling without urticaria, medication related

Diagnosis

Key Features

Epiglottitis

4 D's: Drooling, dysphagia, dysphonia, distress

Bacterial tracheitis

Follows viral croup, toxic, high fever

Foreign body aspiration

Sudden, choking episode, unilateral findings

Retropharyngeal abscess

Neck stiffness, drooling, uvula deviated

Peritonsillar abscess

Older child, trismus, muffled voice

Angioedema

Medication-related swelling, no fever

Laryngomalacia

Chronic stridor since birth, improves with prone

Subglottic stenosis

History of intubation

Vascular ring

Chronic stridor, feeding difficulties

Finding

Diagnosis

"Steeple sign"

Croup (subglottic narrowing)

"Thumbprint sign"

Epiglottitis (swollen epiglottis)

Widened prevertebral space

Retropharyngeal abscess

Subglottic narrowing

Croup; may be normal

Route

Dose

Notes

PO (preferred)

0.15-0.6 mg/kg (max 10-16 mg)

Single dose

Same dose

If vomiting or unable to take PO

Same dose

Rarely needed

Drug

Dose

Prednisolone

1-2 mg/kg PO

Budesonide nebulized

2 mg (less effective than dexamethasone)

Formulation

Dose

Racemic epinephrine 2.25%

0.5 mL in 2.5-3 mL NS

L-epinephrine 1:1000

0.5 mg/kg (max 5 mg = 5 mL)

Situation

Follow-Up

Discharged, improving

PCP in 24-48 hours if not improved

Recurrent croup (> episodes)

ENT referral for airway evaluation

Metric

Target

Rationale

Dexamethasone given

>5%

Reduces morbidity, ED return

Observation ≥3h post-epinephrine

100%

Prevent rebound

Caregiver education on warning signs

100%

Safety

Avoid routine labs/imaging

>0%

Reduce unnecessary testing

Avoid antibiotics

>5%

Croup is viral

Diagnostic Pearls

Barky cough = croup: Almost pathognomonic
Stridor at rest = moderate-severe: Needs treatment
High fever + toxic = not simple croup: Think bacterial tracheitis or epiglottitis
"Steeple sign" on X-ray: Not required, but confirmatory
Recurrent croup may have underlying cause: Consider ENT referral
Rare in infants <6 months: Think congenital airway

Treatment Pearls

Dexamethasone for ALL severities: Even mild croup benefits
Single dose is sufficient: No need for multi-day steroids
Epinephrine works fast: But wears off in 2 hours
Observe after epinephrine: Minimum 3-4 hours
Keep child calm: Agitation worsens obstruction
Mist therapy unproven: But harmless if it helps

Disposition Pearls

Discharge most croup: With steroids on board
Don't discharge within 3-4 hours of epinephrine: Rebound risk
Recurrent croup needs follow-up: Evaluate for underlying cause
Parent education is essential: Know when to return