Croup is a common infection of the upper air passages that causes swelling around the voice box, windpipe, and bronchial tubes, setting off a characteristic dog- or seal-like cough and wheezing. Infants and toddlers are most commonly affected, but the illness is not usually serious, and home treatments are generally quite useful.


There are two types of croup: infectious and non-infectious or spasmodic. Viruses such as influenza and adenovirus, and sometimes bacteria, cause infectious croup. The microbes spread easily through dirty hands, coughing, and sneezing. The virus attacks the upper respiratory system, then travels down the throat.

Spasmodic croup is not caused by an infection. It often runs in families. This condition manifests suddenly. Sometimes, it is difficult to determine whether a croup case is infectious or spasmodic.

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Inflammation triggers a cycle of crying and coughing, which sounds like a high-pitched seal or dog bark, in addition to irritability and anxiety that all feed on each other. Hoarseness and labored breathing usually accompany the illness, and children may also experience a low-grade fever. Croup cases mainly appear during the fall and winter months and last five or six days.

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Stridor is a signature symptom of croup typically heard when an affected child breathes in. It is a high-pitched whistling sound that often frightens parents as croup symptoms increase. Stridor occurs because of obstructed air passage and can be acquired or congenital. It is a clinical sign, not a diagnosis in itself.

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Who Is Commonly Affected

Croup usually affects children between six months and three years. Their small, developing airways and immune systems are more susceptible to viral and bacterial infections. Most cases occur in one-year-olds, but the condition can develop in infants as young as three months and in older children up to 15 years old. Adults can contract croup, but this is extremely rare.

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Most croup cases are mild and clear up within 48 hours. Some children experience symptoms for up to two weeks, however, and middle ear infections and pneumonia may follow. In a small percentage of young children, air passages swell to the point of interfering with breathing. A secondary bacterial infection of the trachea— bacterial tracheitis — occurs rarely, causing breathing difficulty that requires emergency medical attention.

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When checking for croup, a pediatrician will assess the child’s symptoms and ask about close contact with anyone with a cough or cold. The doctor will also review the child’s vaccination records. A diagnosis of croup is based on the symptoms and patient history, along with a physical examination. Severe or atypical cases may require X-rays or other tests to identify or rule out more serious underlying causes.

When Baby's Cold Turns into Croup


Home Treatments

Parents can treat most croup at home. Inhaling moist air from a vaporizer or cool-mist humidifier can ease breathing difficulties. If these are not available, letting the steam from a hot shower fill the bathroom for 20 minutes can achieve the same results. Having the child stand in front of an open freezer for about 10 minutes may also help.

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What Not to Do

Most croup cases resolve on their own in a few days. Pediatricians often advise against giving over-the-counter cough or cold medicines to infants and young children to treat this illness, due to their potential side effects. Research also suggests that these medications are no more effective than placebos.

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When to Call a Doctor

Seek medical attention if symptoms appear severe or worsening, or if they do not respond to home treatment after three to five days. Contact a pediatrician if your child

  • Breathes at a faster rate than normal
  • Struggles to breath
  • Has difficulty swallowing
  • Makes high-pitched wheezing noises when breathing in and out
  • Develops grayish or blue skin around the mouth, nose, or fingernails

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Preventing croup is about as challenging as staving off colds and flu, so take the same precautions to help keep children healthy, especially during the most likely seasons. Wash hands frequently and avoid contact with sick individuals. If the child is old enough, teach them to cough or sneeze into their elbow. Keep up with vaccinations for protection against dangerous upper respiratory infections such as diphtheria and Haemophilus influenzae.

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