Croup refers to an infection of the upper airway, which obstructs breathing and causes a characteristic barking cough.

The cough and other signs and symptoms of croup are the result of swelling around the voice box (larynx), windpipe (trachea) and bronchial tubes (bronchi). When a cough forces air through this narrowed passageway, the swollen vocal cords produce a noise similar to a seal barking. Likewise, taking a breath often produces a high-pitched whistling sound (stridor).

Croup typically occurs in younger children. Croup usually isn't serious and most children can be treated at home.


Croup often begins as a typical cold. If there's enough inflammation and coughing, a child will develop:

  • Loud barking cough that's further aggravated by crying and coughing, as well as anxiety and agitation, setting up a cycle of worsening signs and symptoms
  • Fever
  • Hoarse voice
  • Breathing that may be noisy or labored

Symptoms of croup are typically worse at night and usually last for three to five days.

When to see a doctor

If your child's symptoms are severe, worsen or last longer than three to five days or aren't responding to home treatment, contact your child's doctor.

Seek immediate medical attention if your child:

  • Makes noisy, high-pitched breathing sounds both when inhaling and exhaling
  • Makes high-pitched breathing sounds when not crying or agitated
  • Begins drooling or has difficulty swallowing
  • Seems anxious and agitated or fatigued and listless
  • Breathes at a faster rate than usual
  • Struggles to breathe
  • Develops blue or grayish skin around the nose, mouth or fingernails (cyanosis)

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Croup is usually caused by a viral infection, most often a parainfluenza virus.

Your child may contract a virus by breathing infected respiratory droplets coughed or sneezed into the air. Virus particles in these droplets may also survive on toys and other surfaces. If your child touches a contaminated surface and then touches his or her eyes, nose or mouth, an infection may follow.

Risk factors

Most at risk of getting croup are children between 6 months and 3 years of age. Because children have small airways, they are most susceptible to having more symptoms with croup.


Most cases of croup are mild. In a small percentage of children, the airway swells enough to interfere with breathing. Rarely, a secondary bacterial infection of the trachea can occur, resulting in trouble breathing and requiring emergency medical care.

Only a small number of children seen in the emergency room for croup require hospitalization.


To prevent croup, take the same steps you use to prevent colds and flu.

  • Frequent hand-washing is the most important.
  • Keep your child away from anyone who's sick.
  • Encourage your child to cough or sneeze into his or her elbow.

To stave off more-serious infections, keep your child's vaccinations current. The diphtheria and Haemophilus influenza type b (Hib) vaccines offer protection from some of the rarest — but most dangerous — upper airway infections. There isn't a vaccine yet that protects against parainfluenza viruses.

Oct. 02, 2021
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