What is croup in children?

Croup is a common viral illness that affects young children, causing swelling of the upper airways in the neck. Typical symptoms include a loud, barking cough and sometimes fever; in more serious cases the swelling can make breathing difficult. Croup often shows up at night — for example, a child who sleeps fine but wakes with a sudden seal‑like bark and noisy breathing — and many cases follow a mild cold.

Most cases are mild and can be managed at home, but contact your child’s doctor or urgent care right away if your child has marked difficulty breathing, is unusually sleepy, or has blue‑tinged lips or face.

What causes croup in a child?

Most cases of croup are caused by viruses that inflame the upper airway — the area around the voice box (larynx) and the upper part of the windpipe (trachea). Less commonly, bacteria, allergies, or stomach reflux can lead to similar swelling. Common viruses linked with croup include:

  • Parainfluenza virus
  • Respiratory syncytial virus (RSV)
  • Influenza (the flu)
  • Adenovirus
  • Enteroviruses
  • SARS‑CoV‑2 (COVID‑19) has been reported to cause croup in some children

Croup spreads when an infected person passes virus droplets or secretions to others. The viruses mainly inflame the nose and throat and the upper airways (larynx and the top portion of the trachea), causing the characteristic swelling and noisy breathing. Typical incubation and contagious periods depend on the specific virus, but children are often contagious while they have cold‑like symptoms; keep a sick child home until they are recovering and follow your health provider or local guidance on isolation.

Which children are at risk for croup?

Croup most often affects younger children because their airways are smaller — even a small amount of swelling can make breathing much harder. It’s most common in children aged about 3 months to 5 years, with a peak incidence around age 2. Older children and adults are less likely to have classic croup because their larger airways tolerate swelling better.

Some children have higher risk for more serious illness — for example, very young infants, children born prematurely, or those with underlying lung disease or neuromuscular problems. At night, watch infants and toddlers closely for sudden barking cough or noisy breathing, and seek medical advice if you’re worried.

What are the symptoms of croup in a child?

Croup symptoms can change as the illness progresses. Many children start with cold‑like signs and then develop classic upper‑airway symptoms. Common symptoms include:

  • Runny or stuffy nose and a mild cough
  • A cough that becomes a loud, barking or “seal‑like” cough
  • Hoarseness or loss of voice (laryngitis)
  • Fever (may be present with viral infection)
  • A high‑pitched whistling or noisy intake of breath (stridor), especially when breathing in

Symptoms are often worse at night and may wake your child. Many children improve in about 3 to 7 days, but watch closely — croup can change quickly. Mild croup can be managed at home, but seek medical care right away if you notice any of the following emergency signs:

  • Marked difficulty breathing, fast breathing, or working hard to breathe (retractions)
  • Bluish or gray lips or skin, or severe paleness
  • Very little interest in drinking or extreme sleepiness/lethargy
  • Drooling or trouble swallowing (may indicate a different, urgent condition)

If your child has emergency signs, call 911 or go to the nearest emergency department. For less severe symptoms, contact your child’s doctor or urgent care to discuss next steps and whether treatment (such as a steroid) is recommended.

How is croup diagnosed in a child?

Croup is usually diagnosed by your child’s doctor based on the medical history and a physical exam. Clinicians listen for the characteristic barking cough and stridor and watch for signs such as fast breathing, chest retractions, or low oxygen levels. Most cases do not need imaging or blood tests.

If the presentation is unusual or the provider suspects another problem (for example, a foreign body, epiglottitis, or bacterial tracheitis), the doctor may order tests such as a neck or chest X‑ray, pulse oximetry to check oxygen saturation, or other studies. For routine croup, diagnosis remains clinical — contact your child’s doctor if your child develops the symptoms listed earlier or if breathing worsens.

How is croup treated in a child?

Treatment for croup depends on your child’s age, overall health, and how severe the symptoms are. Mild cases are often managed at home with supportive care, while moderate to severe croup may require treatment from a doctor or hospital.

What doctors may do

For more than mild symptoms, a healthcare provider may recommend or give:

  • A steroid dose (commonly dexamethasone) to reduce airway swelling — a single dose often helps even in mild to moderate croup and can be given by mouth or by injection if necessary.
  • Nebulized treatments (such as nebulized epinephrine) in the emergency setting for children with significant breathing difficulty or stridor at rest; these are used for moderate to severe croup and usually require monitoring in clinic or hospital.
  • Supportive hospital care for severe croup, including oxygen or close observation; rare cases may need more advanced airway support.

Home care for mild croup

If your child has mild symptoms, these safe steps may help ease breathing and comfort them at home:

  • Keep your child calm — crying can make breathing harder. Comfort them and stay with them, especially at night.
  • Offer plenty of fluids and let them rest.
  • Use a cool‑mist humidifier in the child’s room or sit with the child in a steamy bathroom (run hot shower to fill the room with steam) for short periods — be cautious with hot water and never leave young children unattended. In some cases, taking the child outside into cool night air can improve breathing.
  • Avoid smoke exposure — do not smoke in the home, as secondhand smoke can worsen cough and airway irritation.
  • For fever or discomfort, your child’s provider may recommend acetaminophen or ibuprofen (use dosing guidance for age/weight and avoid aspirin in children).

When to seek medical care

Croup can change quickly. Seek urgent medical attention or call 911 if your child has any of these:

  • Severe or rapidly worsening difficulty breathing, noisy breathing at rest (stridor that does not improve), or obvious chest retractions
  • Bluish lips, face, or very pale or mottled skin
  • Very sleepy, hard to wake, not drinking, or drooling and unable to swallow

Your child’s doctor can advise when a steroid is appropriate and whether an in‑clinic treatment (like nebulized medication) or hospital observation is needed. Antibiotics are not useful for viral croup unless a bacterial infection is confirmed. If you are unsure how serious your child’s symptoms are, contact your child’s doctor or local urgent care for advice.

What can I do to prevent croup in my child?

You can reduce the chance that your child catches or spreads the viruses that cause croup by following simple infection‑control and care steps:

  • Wash hands often with soap and water and teach your child good handwashing — this is the best way to stop germs from spreading.
  • Avoid sharing cups, utensils, and food when someone in the household is sick — respiratory viruses spread through droplets and shared items.
  • Keep a sick child home until they are improving — follow local guidance or your pediatrician’s advice (many guidelines recommend staying home until symptoms are clearly better and fever‑free without medication for a set period).

Additional prevention steps that can help protect against some causes of croup include keeping up with routine vaccinations (for example, annual influenza vaccine) and avoiding exposure to secondhand smoke, which can irritate the airways.

If you’re unsure whether your child should stay home or need care, call your pediatrician or local urgent care for advice — they can guide you based on your child’s symptoms and your local school or daycare policies.