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Croup is inflammation or infection of the voice box and windpipe. The inflammation causes tissue in the respiratory tract to swell, so a child must work harder for air to reach the lungs. Croup occurs in young children. As children grow older, the air passages widen, so swelling enough to block breathing is less likely in older children.

Upper Respiratory System in a Child

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Causes of croup include:

  • Viral infections, including:
    • Parainfluenza
    • Paramyxovirus
    • Influenza virus type A
    • Respiratory syncytial virus
    • Adenovirus
    • Rhinovirus
    • Enterovirus
    • Coxsackievirus
    • Enteric cytopathogenic human orphan virus
    • Reovirus
    • Measles virus

Tests for specific viruses are rarely performed, so the actual cause of croup is usually not known.

Conditions that resemble croup can also be caused by:

  • Bacterial infections
  • Allergies
  • Softening of cartilage in the larynx (windpipe)

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

  • Age: 3 years old or younger
  • Attending day care
  • History of croup
  • Family history of croup
  • Frequent upper respiratory infections
  • Colder months: October through March


Symptoms are usually preceded by an upper respiratory infection. Croup symptoms come on suddenly, often at night.

Symptoms may include:

  • Cough spasms
  • Cough that sounds like a barking seal
  • Hoarseness
  • Fever
  • Harsh, high-pitched breath sounds, especially when crying or upset
  • Trouble breathing
  • Poor appetite and fluid intake

More serious symptoms of croup that may require immediate medical attention include:

  • Bluish color of the nails and lips, or around the mouth—This is an absolute emergency. Call 911.
  • Decreased alertness—This is also a very serious symptom; call 911.
  • Restlessness or agitation—This can be due to dangerous lack of oxygen.
  • Struggling for each breath
  • Harsh, high-pitched breath sounds even at rest
  • Trouble swallowing
  • Drooling
  • Inability to speak due to trouble breathing


The doctor will ask about your child's symptoms and medical history, and perform a physical exam.

Tests, if indicated, may include:

  • Blood tests—to check for signs of infection
  • Neck x-rays—to look for changes associated with croup
  • Laryngoscopy—a thin tube inserted into the mouth to look at throat tissue (A culture of mucus from the windpipe may be taken during this procedure and tested for infection.)


Treatment aims to keep the airway open while the infection resolves on its own in 5-7 days. Severe symptoms usually resolve in 3-4 days.

Therapies include:

Self-care and Humidification

  • Try to keep your child calm and quiet. Crying can make the symptoms worse.
  • Moist air will help to keep the airways open. Take the child into the bathroom and close the door. Let the hot water run in the shower and fill the room with moisture. Sit with the child in the moist air for 15-20 minutes. Never leave a child unattended with hot water running or a tub of water nearby.
  • Repeat the bathroom steam treatments as needed. Or try running a warm- or cold-water humidifier in your child's room.
  • If the moist-air treatments do not help breathing or your child's condition is getting worse, seek medical care.
  • Call the doctor or emergency medical services (911). Do not hesitate to call even if the attack occurs during the night.


The doctor may prescribe steroids to reduce swelling in the airways as this treatment has been shown to benefit croup and may keep a child from becoming sick enough to need hospitalization. Breathing treatments with a medicine called racemic epinephrine may provide temporary help until steroid medications (usually dexamethasone) start to work. Since most croup is caused by a viral infection, antibiotics are not indicated unless there is some other accompanying problem like an ear infection or pneumonia .

Hospital Care

  • A child with serious croup may be placed in a croup tent. Cool, moist air is delivered inside this plastic tent.
  • Medications may be given to treat inflammation and respiratory distress.
  • If the child continues to get worse, a breathing tube may be inserted in the throat to help keep the airway open.
  • Fluids can be given through a vein if necessary.
  • The child's oxygen level and heart rhythm are monitored.
  • In severe cases, a surgical procedure called a tracheostomy can be performed to keep the airway open.


Croup usually occurs in response to an upper respiratory infection. Minimizing exposure to viruses that cause colds and flu may help prevent croup. Yearly influenza immunization can prevent those cases of croup due to Influenza A. Influenza immunization is strongly recommended for all children between the ages of 6 months to 5 years.


American Academy of Pediatrics



About Kids Health

BC Health Guide


American Academy of Pediatrics website. Available at: .

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Griffith's 5-Minute Clinical Consult . Lippincott, Williams, and Wilkins; 2001.

Kleigman RM, Jensen HB, Behrman RE, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders Elsevier; 2007.

Nelson Textbook of Pediatrics .16th ed. WB Saunders Company; 2000.

Principles and Practice of Infectious Diseases . 5th ed. Churchill Livingstone, Inc; 2000.

Last reviewed November 2007 by Kari L. Kassir, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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