Croup

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 13 Jun 2025

Last updated: 28 Apr 2023

Croup is a common cause of acute respiratory distress in children.

Acute onset of seal-like barky cough in moderate to severe cases accompanied by stridor and sternal/intercostal indrawing.

Careful history and physical examination sufficient for confirming clinical diagnosis and ruling out potentially serious differentials.

Orally administered corticosteroids are the mainstay for all levels of severity, combined with nebulised epinephrine (adrenaline) in moderate to severe croup to provide temporary relief of the symptoms of upper-airway obstruction.

Definition

Croup, also known as laryngotracheobronchitis, is a common respiratory disease of childhood, characterised by the sudden onset of a seal-like barky cough, often accompanied by stridor, voice hoarseness, and respiratory distress. The symptoms are a result of upper-airway obstruction due to generalised inflammation of the airways, as a result of viral infection (typically parainfluenza virus types 1 or 3).

History and exam

Key diagnostic factors

symptoms increasing with agitation
distinctive seal-like barky cough
age 6 months to 6 years

Full details

Other diagnostic factors

male sex
peak season late autumn
prodromal symptoms
abrupt onset of symptoms
symptoms worse at night
hoarse voice
respiratory distress (sternal/intercostal indrawing, stridor)
persistent agitation
lethargy
asynchronous chest wall and abdominal movement
fatigue
signs of hypoxia (pallor or cyanosis)
signs of hypercapnia (decreased level of consciousness secondary to rising PaCO₂)

Full details

Risk factors

age 6 months to 6 years
male sex
prior intubation

Full details

Diagnostic investigations

1st investigations to order

clinical exam

Full details

Investigations to consider

x-ray anteroposterior and lateral neck

Full details

Treatment algorithm

ACUTE

mild (no stridor at rest)

moderate (stridor at rest; no agitation or lethargy)

severe (stridor at rest with agitation or lethargy)

Contributors

Authors

Candice Bjornson, MSc, MD, FRCPC

Associate Professor

University of Calgary

Calgary

Canada

Disclosures

CB declares that she has no competing interests. CB is the author of several references in this topic.

David Johnson, MD

Professor

Department of Pediatrics and Physiology and Pharmacology

University of Calgary

Calgary

Canada

Disclosures

DJ declares that he has no competing interests. DJ is the author of several references in this topic.

Peer reviewers

Ken Farion, MD

Assistant Professor

Pediatrics and Emergency Medicine

University of Ottawa

Ottawa

Canada

Disclosures

KF declares that he has no competing interests.

Doreen Matsui, MD, FRCPC

Associate Professor

Departments of Paediatrics and Medicine

Children's Hospital of Western Ontario

London

Ontario

Canada

Disclosures

DM declares that she has no competing interests.

Jeremy Hull, MBBS

Consultant Paediatrician

Children's Hospital and West Wing

John Radcliffe Hospital

Oxford

Disclosures

JH declares that he has no competing interests.

Steve Cunningham, MBBS, PhD

Consultant Respiratory Paediatrician

Department of Respiratory & Sleep Medicine

Royal Hospital for Sick Children

Edinburgh

Disclosures

SC declares that he has no competing interests.

Donna J. Lee, MD

Pediatric Pulmonology,

Joseph M. Sanzari Children's Hospital,

Hackensack Meridian Health

Hackensack

Disclosures

DL declares that he has no competing interests.

Deepak Mehta, MD, FRCS ( Oto)

Professor of Otolaryngology,

Director Pediatric Aerodigestive Center,

Baylor College of Medicine,

Texas Children’s Hospital,

Houston

Disclosures

DM declares that he has no competing interests.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Johnson D, Klassen T, Kellner J. Diagnosis and management of croup: Alberta Medical Association clinical practice guidelines. Alberta: Alberta Medical Association; 2015 [internet publication].Full text

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Bacterial tracheitis
- Epiglottitis
- Foreign body in the upper airway
More Differentials
Guidelines
- Acute management of croup in the emergency department
- Guideline for the diagnosis and management of croup
More Guidelines
Videos
Stridor
More videos
Log in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer

Croup

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

mild (no stridor at rest)

moderate (stridor at rest; no agitation or lethargy)

severe (stridor at rest with agitation or lethargy)

Contributors

Authors

Candice Bjornson, MSc, MD, FRCPC

Disclosures

David Johnson, MD

Disclosures

Peer reviewers

Ken Farion, MD

Disclosures

Doreen Matsui, MD, FRCPC

Disclosures

Jeremy Hull, MBBS

Disclosures

Steve Cunningham, MBBS, PhD

Disclosures

Donna J. Lee, MD

Disclosures

Deepak Mehta, MD, FRCS ( Oto)

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Videos

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice