What is the cause of stridor?

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Last updated: February 19, 2025View editorial policy

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From the Guidelines

Stridor is typically caused by an upper airway obstruction, which can be due to various factors such as congenital anomalies, infections, or foreign bodies 1.

Common Causes of Stridor

  • Laryngomalacia is the most common congenital laryngeal anomaly and a frequent cause of persistent stridor in children 1
  • Laryngoceles and saccular cysts, laryngeal webs and atresia, laryngotracheal stenosis, laryngeal and tracheal clefts, congenital neoplasms such as hemangiomas, bifid epiglottis, and ventral cleft of the larynx are other congenital anomalies that can cause stridor 1
  • Paralysis of the vocal cords is another common cause of stridor in infants and children, often resulting from congenital anomalies of the central nervous system 1
  • Infantile hemangiomas can also cause stridor, particularly when they involve the airway, and can lead to biphasic stridor and a barky cough 1
  • Upper airway injuries from endotracheal intubation, such as vocal cord injury, edema, and hematoma, can also result in stridor 1

In cases of stridor, it is essential to assess the patient's airway, breathing, and circulation (ABCs) immediately and provide supportive care as needed, such as oxygen therapy or medications to reduce inflammation and swelling in the airway 1. If the stridor worsens or the patient experiences severe respiratory distress, immediate medical attention is required, and interventions such as intubation or other advanced airway management techniques may be necessary to secure the airway.

From the Research

Causes of Stridor

  • Stridor is caused by abnormal air passage into the lungs and can exist in different degrees, resulting from obstruction located anywhere in the extra-thoracic (nose, pharynx, larynx, trachea) or intra-thoracic airway (tracheobronchial tree) 2, 3, 4.
  • The cause of stridor can be acute or chronic, congenital or acquired, and may be located in the extrathoracic airway (nose, pharynx, larynx, and trachea) or the intrathoracic airway (tracheobronchial tree) 3.
  • Laryngotracheal inflammation (croup) is the most common cause of acute stridor, while laryngotracheomalacia is the most common cause of congenital, chronic stridor 2.
  • Stridor can also be caused by noninfectious and/or congenital conditions, as well as life-threatening etiologies, such as bacterial tracheitis and retropharyngeal abscess 5, 6.

Types of Stridor

  • Stridor can be classified as acute or chronic, and may be caused by various conditions, including inflammation, infection, foreign body inhalation, and congenital anomalies 3, 4.
  • Acute stridor can be caused by croup, bacterial tracheitis, and retropharyngeal abscess, while chronic stridor can be caused by laryngotracheomalacia and other congenital conditions 2, 6.

Diagnosis and Management

  • Stridor is a clinical sign and not a diagnosis, and the underlying cause must be sought through history, physical examination, and further investigations, such as flexible airway endoscopy 2, 4.
  • The management of stridor depends on the underlying cause and may include reduction of airway inflammation, treatment of bacterial infection, and emergent airway stabilization or surgical management 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Assessment and causes of stridor.

Paediatric respiratory reviews, 2016

Research

Management of airway obstruction and stridor in pediatric patients.

Pediatric emergency medicine practice, 2017

Research

Acute upper airway obstruction.

Indian journal of pediatrics, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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