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."