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What is croup?

Croup is a viral infection of the vocal cords, voice box (larynx), and windpipe (trachea).

Symptoms of a croup include:

  • a tight, low-pitched "barking" cough
  • a hoarse voice

You may hear a harsh, raspy, vibrating sound when your child breathes in. This is called stridor. Stridor is usually present only with crying or coughing. As the disease becomes worse, stridor also occurs when your child is sleeping or relaxed. With severe croup, breathing may be difficult.

What causes croup?

Croup is usually part of a cold. Swelling of the vocal cords causes hoarseness. Stridor is caused by the opening between the vocal cords becoming more narrow.

How long will it last?

Croup usually lasts for 5 to 6 days and generally gets worse at night. During this time, it can change from mild to severe and back many times. The worst symptoms are seen in children under 3 years of age.

How is it treated?

First Aid For Stridor

If your child suddenly develops stridor or tight breathing, do the following:

  • Inhalation of warm mist

    Warm moist air seems to work best to relax the vocal cords and break the stridor. The simplest way to provide this is to have your child breathe through a warm, wet washcloth placed loosely over his nose and mouth. Another good way, if you have a humidifier (not a hot vaporizer), is to fill it with warm water and have your child breathe deeply from the stream of humidity.

  • The foggy bathroom

    In the meantime, have a hot shower running with the bathroom door closed. Once the room is all fogged up, take your child in there for at least 10 minutes. Try to help your child not be afraid by cuddling or reading a story.

  • Cold air

    Cold air sometimes relieves the stridor. If it is cold outside, take your child outdoors. You can also hold your child in front of an open refrigerator.

Most children settle down with the above treatments and then sleep peacefully through the night. If your child continues to have stridor, call your child's health care provider IMMEDIATELY. If your child turns blue, passes out, or stops breathing, call the rescue squad (911).

Home Care for a Croupy Cough (without stridor)

  • Humidifier

    Dry air usually makes a cough worse. Keep the child's bedroom humidified. Use a humidifier if you have one. Run it 24 hours a day. Otherwise, hang wet sheets or towels in your child's room.

  • Warm fluids for coughing spasms

    Coughing spasms are often due to sticky mucus caught on the vocal cords. Warm fluids may help relax the vocal cords and loosen up the mucus. Use clear fluids (ones you can see through) such as apple juice, lemonade, or herbal tea. Give warm fluids only to children over 4 months old.

  • Cough medicines

    Medicines are less helpful than either mist or drinking warm, clear fluids. Children over 4 years old can be given cough drops for the cough. Children over 1 year of age can be given 1/2 to 1 teaspoon of corn syrup as needed to thin the secretions. If your child has a fever (over 102F, or 38.9C), you may give him acetaminophen (Tylenol) or ibuprofen (Advil).

  • Close observation

    While your child is croupy, sleep in the same room with him. Croup can be a dangerous disease.

  • Smoke exposure

    Never let anyone smoke around your child. Smoke can make croup worse.

  • Contagiousness

    The viruses that cause croup are quite contagious until the fever is gone or at least during the first 3 days of illness. Since spread of this infection can't be prevented, your child can return to school or child care once he feels better.

When should I call my child's health care provider?


  • Breathing becomes difficult (when your child is not coughing).
  • Your child starts drooling or spitting, or starts having great difficulty swallowing.
  • The warm mist fails to clear up the stridor in 20 minutes.
  • Your child starts acting very sick.

Call within 24 hours if:

  • The attacks of stridor occur more than 3 times.
  • A fever lasts more than 3 days.
  • Croup lasts more than 10 days.
  • You have other concerns or questions.
Written by B.D. Schmitt, M.D., author of "Your Child's Health," Bantam Books.
Published by McKesson Provider Technologies.
Last modified: 2006-03-01
Last reviewed: 2006-03-02
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.
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