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Humidity May Not Help Kids With Croup

Most Children Get Better Without Treatment

Medically Reviewed by Louise Chang, MD on March 14, 2006
From the WebMD Archives

March 14, 2006 -- Generations of parents have battled croup with humidity, but new research shows it may not actually work.

The approach has been long recommended but a rigorously designed study published in the latest Journal of the American Medical Association shows little evidence that it's effective.

Pediatric emergency medicine specialist Dennis Scolnik, MB, who led the study team, tells WebMD that in the vast majority of cases, the seal-like, barking cough and labored breathing characteristic of croup resolve within an hour or so, with or without treatment.

"For a parent who has never been through it, the symptoms of croup can be more alarming than a seizure," Scolnik says. "Typically, children go to bed perfectly well or with a slight cold and wake up in the night with an alarming cough, gasping for breath."

2/3 Didn't Need Treatment

Roughly 5% of children develop viral croup before they reach the age of 6, and about 1% of kids with croup require hospitalization when upper airways become dangerously constricted.

While the cough and labored breathing usually resolve in a short time, many parents seek emergency care for their children because their symptoms are often so scary. When breathing is severely restricted, patients are generally treated with inhaled ephinephrine or steroids.

When symptoms are not so severe, however, humidity still may be the treatment of choice.

Steam and humidity are thought to soothe inflamed airways and decrease mucus, but there has been little scientific study of the approach.

The new study included 140 children with moderate to severe croup symptoms treated in the emergency department of Toronto, Ontario's Hospital for Sick Children.

Only children whose symptoms lasted for 30 minutes or more after arriving at the hospital were chosen for the study.

Roughly 300 other children with croup who sought treatment during the same time did not qualify for the study because their symptoms resolved on their own in less time.

"Two-thirds of the children who came to the ER for treatment got better within 30 minutes without it," says pediatric infectious disease specialist John S. Bradley, MD, FAAP. "ER physicians see this time and time again. But we can't say which children will get better on their own and which ones won't."

Approximately one-third of the children in the study whose symptoms did not resolve on their own were treated for 30 minutes with high humidity, using a device designed by the researchers to deliver the optimal amount of humidity to the children's airways.

The rest of the children were treated with lower humidity, at dosages more typically delivered in an ER or with a home humidifier.

The researchers found that high humidity was no more effective than low humidity in the emergency department setting.

"Our results suggest that the use of humidity in children with croup seen in emergency departments is not warranted," they concluded.

Cool Night Air May Help Croup

Scolnik says the same is true for children with moderate to severe croup symptoms treated at home, even though humidifiers or the steamy bathroom treatment may appear to be useful.

The American Academy of Pediatrics recommends the approach, telling parents through its web site to sit in a steamy bathroom with their child for 15 to 20 minutes.

"Steam almost always works," the AAP public education statement on croup states.

It may appear to work, Scolnik says, but it is more likely that a parent's efforts to comfort and calm the sick child are what really help.

"Parents are doing all the right things when they sit in a steamy bathroom with a child with croup, and the setting is warm and comforting," he says. "But the humidity probably isn't adding much."

Wrapping the child in blankets and taking him outside if the air is cool may help, he says. But this approach has not been well tested either.

Bradley tells WebMD that few of the long-relied on, home treatments for croup and many other childhood illnesses have been subjected to scientific scrutiny.

He is chief of the infectious disease division of the Children's Hospital in San Diego, and he serves of the AAP's Committee on Infectious Diseases.

"My hat is off to these researchers for doing this type of rigorous research on a treatment that has so much tradition behind it," he says. "There are many, many treatments like this that have been used for generations, even though we don't really know if they work. We need more studies like this one."

Recognizing Trouble Signs

While most children with croup will get better within a short time, some do need urgent medical care.

The AAP recommends seeking treatment immediately if the child:

  • Makes a whistling sound that gets louder with each breath
  • Can't speak for lack of breath
  • Seems to be struggling to get a breath
  • Seems very pale or has a bluish mouth or fingernails
  • Drools or has extreme difficulty swallowing saliva
  • Keeps making the abnormal, high-pitched breathing sound, known medically as stridor, while resting

Show Sources

SOURCES: Scolnik, D. Journal of the American Medical Association, March 15, 2006; vol. 295: pp. 1274-1280. Dennis Scolnik, MD, ChB, division of pediatric emergency medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; and associate professor, University of Toronto. John S. Bradley, director, division of infectious diseases, Children's Hospital, San Diego, Calif; and AAP Committee on Infectious Diseases. American Academy of Pediatrics public education statement on croup, AAP web site.
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