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What Is Croup?

Croup is caused by an acute viral infection of the upper respiratory tract. It is also called laryngotracheobronchitis since it affects the larynx, trachea, and bronchi. This infection results in inflammation, increased mucus production, and swelling of the upper airways. Although croup usually resolves on its own, some children with croup will require admission to the hospital. Croup continues to be one of the most common causes of respiratory distress in young children.

  • Children between the ages of 6 months and 3 years of age are most likely to get croup. This common viral illness is estimated to occur annually in 5% of children between the ages of 6 months and 3 years and is the most common cause of stridor (upper airway wheezing during inspiration) in this age group. Croup is rarely seen in adults because their larger breathing passages (trachea and larynx) can accommodate the inflammation without producing symptoms.
  • Some children appear to be particularly prone to croup and have a number of infections. Boys are more prone than girls, with peak seasonal outbreaks in late fall and winter.
  • Croup should be differentiated from more serious medical diagnoses, including acute epiglottitis, bacterial tracheitis, severe allergic reactions, or an inhaled foreign body.

What Causes Croup?

Croup is most commonly caused by a viral respiratory infection that is easily passed among children. Common viral causes include parainfluenza (responsible for the majority of infections), influenza, adenovirus, respiratory syncytial virus (RSV), and rhinovirus. Prior to the vaccine era, diphtheria caused most cases of croup and was referred to as membranous croup, but today, fortunately, vaccination against diphtheria has made it an exceedingly rare disease.

Medically Reviewed by a Doctor on 11/9/2016

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Patient Comments & Reviews

The eMedicineHealth doctors ask about Croup:

Croup - Symptoms

What symptoms did you or your child experience with croup?

Treatment Overview

Home treatment, such as using a humidifier, can help treat mild to moderate croup. Regardless of treatment, symptoms usually improve gradually within 2 to 5 days.

If your child has severe croup or has not responded to home treatment, medicines may be used to reduce airway swelling. These are usually given in a doctor's office or an emergency room. Medicines usually include:

  • Glucocorticoids, such as dexamethasoneor budesonide(for example, Pulmicort).
  • Epinephrine.

If your child needs extra oxygen, it is given through a nasal cannulaor delivered through an oxygen mask placed over the nose and mouth.

If breathing improves after one or more of these measures, your child will be observed for a short time and sent home. If symptoms do not improve, your child may need hospitalization and further testing.

What to Think About

Over-the-countercough and cold medicines are not helpful for treating croup. These medicines may not be safe for young children. Before you give them to a child, check the label. If you do give these medicines to a child, always follow the directions about how much to give based on the child's age and weight.


Read What Your Physician is Reading on Medscape

Croup »

Croup, also termed laryngotracheitis or laryngotracheobronchitis, is a viral respiratory tract infection.

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