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# Stridor in infants and children

- Approach to a complaint

Stridor is a harsh breathing noise from a narrowed upper airway; its timing and the child's age point to the cause and how urgent it is.

Updated Nov 5, 2026

## Key points

- Inspiratory stridor suggests a laryngeal (supraglottic or glottic) obstruction; biphasic stridor a glottic or subglottic one; expiratory noise a tracheobronchial one.
- Laryngomalacia is the most common cause of stridor in infants; mild cases need only watchful waiting, severe ones (failure to thrive, apnoea) need surgery.
- Croup is the most common acquired cause: barking cough and inspiratory stridor between 6 months and 3 years, usually viral (parainfluenza).
- Never examine the throat with a spatula or send an unstable child for imaging if epiglottitis is suspected: secure the airway first.
- Sudden stridor or choking in a previously well toddler means foreign body until proven otherwise.

## What it is

Stridor is a high-pitched sound produced by turbulent airflow through a narrowed airway; it means upper airway obstruction. In children the airway is small, so even minor swelling can cause severe obstruction. The phase of breathing in which stridor occurs suggests the level, and age and speed of onset separate congenital causes (laryngomalacia is the most common cause of stridor in infants) from acquired ones (croup, epiglottitis, foreign body). This page gives the approach; the diseases are on their condition pages.

## Key questions in the history

- When did it start: from birth or the first weeks (congenital) or suddenly (acquired)?
- Is it worse when feeding, crying or lying down? Are there feeding problems, poor weight gain or cyanosis?
- Fever, drooling, toxic look or tripod posture (epiglottitis, bacterial tracheitis, abscess)?
- Barking cough after a cold (croup)? Choking episode (foreign body)?
- History of intubation (subglottic stenosis)? Vaccination status, especially Haemophilus influenzae type b?

## Causes and classification

- Supraglottis: laryngomalacia, epiglottitis — inspiratory stridor.
- Glottis: vocal fold lesions — inspiratory or biphasic stridor, weak cry.
- Subglottis: croup, subglottic stenosis (often after intubation) — biphasic stridor; the cricoid is a complete ring, so it cannot expand.
- Trachea and bronchi: foreign body, compression — expiratory noise or biphasic.

## Step-by-step approach

- Assess severity first: work of breathing, stridor at rest, colour, consciousness, oxygen saturation; keep the child calm in the parent's arms.
- If there is severe obstruction, drooling or toxic look, call for help and secure the airway; do not examine the throat or lie the child down.
- Define the phase of the stridor and the age and speed of onset.
- Acute with barking cough: treat as croup (corticosteroid; nebulised epinephrine if moderate to severe) and observe.
- Sudden onset after choking: suspect a foreign body and arrange urgent endoscopy.
- Chronic since early infancy, child thriving: probable laryngomalacia, confirmed by flexible laryngoscopy by the specialist.
- Chronic with feeding problems, poor weight gain, apnoea or cyanosis: urgent specialist assessment.

## Main causes of stridor in children

| Cause | Age and onset | Key features |
| --- | --- | --- |
| Laryngomalacia | Infant, chronic | Inspiratory stridor, child otherwise well; worse with severe disease if feeding problems |
| Subglottic stenosis | Infant, often after intubation; or congenital | Biphasic stridor, recurrent «croup» |
| Croup | 6 months to 3 years, after a cold, often at night | Barking cough, hoarse voice, mild fever |
| Epiglottitis | Any age; rare in vaccinated children | Sudden high fever, drooling, toxic look, sitting forward, muffled voice |
| Foreign body | Toddlers, sudden | Choking episode, unilateral wheeze or stridor |

## Red flags

- Stridor at rest, chest retractions, cyanosis or altered consciousness.
- Drooling, inability to swallow, tripod position, toxic appearance.
- Sudden onset after choking.
- Infant with stridor plus poor feeding, failure to thrive, apnoea or cyanosis.
- Stridor in an infant who was intubated, or «croup» that keeps coming back or occurs under 6 months.

## Next step / Initial management

- No routine tests in the acute setting; the diagnosis is clinical, and imaging must never delay securing the airway.
- First-line in croup: oral or parenteral corticosteroid (dexamethasone); nebulised epinephrine for moderate to severe cases, with observation afterwards.
- Refer the same day (emergency, with an airway team) for suspected epiglottitis, foreign body, severe croup or any stridor at rest with distress.
- Refer urgently (within days) to paediatric otolaryngology an infant with stridor and feeding problems, poor weight gain or apnoea; refer on a routine basis a thriving infant with mild stridor for laryngoscopy and follow-up.

## Test yourself

Think of the answer, then tap the question to see it.

## A 6-week-old has inspiratory stridor since birth, feeds well and is gaining weight. Most likely diagnosis and management?

Laryngomalacia, the most common cause of infant stridor; mild disease is managed with watchful waiting after confirmation by flexible laryngoscopy.

## A 2-year-old has a barking cough and inspiratory stridor at night after a cold. What is the first-line treatment?

A corticosteroid (for example dexamethasone); nebulised epinephrine is added if croup is moderate to severe.

## A 4-year-old has sudden high fever, drools and sits leaning forward. What must be avoided?

Examining the throat with a spatula, lying the child down or sending the child for imaging; the airway is secured first by an experienced team.

## What level of obstruction does biphasic stridor suggest?

A glottic or subglottic narrowing (for example subglottic stenosis or croup).

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## Connections

## Related 2

- [Approach to stridor](https://durgical.com/en/ent/approach-to-stridor/)
- [Paediatric ENT: what is different in children](https://durgical.com/en/ent/paediatric-ent-what-is-different-in-children/)

## Related conditions 2

- [Croup (laryngotracheobronchitis)](https://durgical.com/en/conditions/croup/)
- [Acute epiglottitis](https://durgical.com/en/conditions/acute-epiglottitis/)

[← All of ENT](https://durgical.com/en/ent/)

Educational content; it does not replace a medical assessment and is not a clinical instruction. For a real case, follow current guidelines and specialist advice.

Sources: [Stridor in Children](https://www.ncbi.nlm.nih.gov/books/NBK525995/) (StatPearls (NCBI Bookshelf), 2023); [Laryngomalacia](https://www.ncbi.nlm.nih.gov/books/NBK544266/) (StatPearls (NCBI Bookshelf), 2024); [Croup](https://www.ncbi.nlm.nih.gov/books/NBK431070/) (StatPearls (NCBI Bookshelf), 2025); [Epiglottitis](https://www.ncbi.nlm.nih.gov/books/NBK430960/) (StatPearls (NCBI Bookshelf), 2024); [Subglottic Stenosis](https://www.ncbi.nlm.nih.gov/books/NBK563265/) (StatPearls (NCBI Bookshelf), 2023); [Foreign Body Airway Obstruction](https://www.ncbi.nlm.nih.gov/books/NBK553186/) (StatPearls (NCBI Bookshelf), 2024).

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Source: https://durgical.com/en/ent/stridor-in-infants-and-children/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/ent/stridor-in-infants-and-children/