Croup in Babies & Toddlers
Content reviewed against published AAP, CDC, NICE guidelines
Last reviewed:
Croup is a common childhood illness that causes swelling of the voice box (larynx) and windpipe (trachea). It produces a distinctive barking cough that sounds like a seal, along with a harsh squeaky sound when breathing in (stridor). It is most common in children aged 6 months to 3 years.
Key takeaways
- Croup is a common childhood illness that causes swelling of the voice box (larynx) and windpipe (trachea).
- Duration: Barking cough typically lasts 2-3 days, with full resolution in 5-7 days. Worst on nights 2-3.
- Go to ER if: Stridor at rest that is loud and constant
- No vaccine currently available
Symptoms
How It Presents by Age
0-6 months
Uncommon in very young infants. When it occurs, it can be more serious due to smaller airways. Any stridor in this age group warrants urgent medical evaluation.
Risk level: High if affected
6-12 months
Classic barking cough and stridor. Airways are small so swelling causes more obstruction proportionally. Often worse at night.
Risk level: Moderate
1-3 years
Most common age for croup. Typical barking cough, often starts suddenly at night. Most cases are mild and resolve with home treatment.
Risk level: Low to moderate
3+ years
Less common as airways are larger. When it occurs, usually milder. Consider other diagnoses if severe.
Risk level: Low
Treatment
Cool air
Taking the child outside into cool night air often provides rapid temporary relief by reducing swelling.
Corticosteroids
A single dose of dexamethasone (oral) is the standard treatment and reduces swelling. Works within 2-4 hours and lasts 24-72 hours.
Nebulized epinephrine
For moderate to severe cases in the ER. Provides rapid but temporary relief (lasts 1-2 hours).
Supportive care
Keep the child calm (crying worsens stridor), offer fluids, and use a cool-mist humidifier.
Home Care
- Take your child outside into cool night air for 10-15 minutes
- Run a cool-mist humidifier in the bedroom
- Keep your child calm — comfort without overstimulating
- Sit in a steamy bathroom (though evidence is limited)
- Offer clear fluids and popsicles
- Elevate the head of the bed slightly
- Use acetaminophen or ibuprofen for fever and discomfort
When to Worry
Go to the ER if:
- Stridor at rest that is loud and constant
- Severe difficulty breathing — chest retractions, nasal flaring
- Blue or pale color around the lips
- Child cannot speak or cry due to breathing difficulty
- Drooling and unable to swallow (may indicate epiglottitis)
- Child looks very unwell, limp, or lethargic
Call your doctor if:
- First episode of croup for guidance on management
- Stridor continues during the day (not just at night)
- Fever lasts more than 3 days
- Child is drinking less than half their normal amount
- Symptoms are recurring frequently
Keep an eye on:
- Stridor at rest (when child is calm, not just when crying)
- Breathing rate increasing
- Child seems anxious or restless
- Drooling or difficulty swallowing
- Symptoms not improving after 5 days
Prevention
- Frequent handwashing
- Avoid close contact with people who have colds
- Keep your child away from cigarette smoke
- Ensure up-to-date on influenza and parainfluenza vaccines where available
Contagion & Incubation
Incubation
2-6 days
Contagious for
Most contagious during the first few days of symptoms, but may remain contagious for up to 10 days
Duration
Barking cough typically lasts 2-3 days, with full resolution in 5-7 days. Worst on nights 2-3.
Frequently asked questions
How long does croup last?
How does laryngotracheobronchitis spread?
When should I take my baby to the ER?
Can laryngotracheobronchitis be prevented?
When can my child return to daycare?
Sources
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Illnesses
Bottom line
Croup is a viral illness that typically resolves on its own. Seek emergency care if stridor at rest that is loud and constant.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.