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March 14, 2006

SickKids researchers determine humidity is an ineffective therapy for moderate to severe cases of croup

TORONTO -- Researchers at The Hospital for Sick Children (SickKids) have determined that humidity is an ineffective therapy for the common childhood ailment croup. This research is reported in the March 15, 2006 issue of The Journal of the American Medical Association.

Viral croup is the most common childhood cause of upper airway obstruction in children. In adults the infection may manifest as laryngitis, but because of the smaller size and shape of their airway, children tend to show the signs of croup. Croup commonly occurs in spring and fall and is characterized by a cough that sounds like the bark of a seal or a dog.

“Humidity has long been a treatment to relieve the symptoms of croup, however there has previously been very little evidence-based research to confirm that it is an effective therapy and there can be risks associated with this type of treatment,” said the study's lead author, Dr. Dennis Scolnik, a physician in the Divisions of Emergency Services and Clinical Pharmacology and Toxicology and project director at SickKids, and an assistant professor of Paediatrics at the University of Toronto. “Patients can be at risk of burns from the steam and wheezing or electrolyte abnormalities can occur in infants. Because of these risks, we felt that it was important that the positive effects of humidification be substantial enough to warrant its ongoing use.”

A randomized trial of 140 children with moderate to severe croup between the ages of three months and 10 years of age was conducted between 2001 and 2004 in the SickKids Emergency Department. The study found that humidity did not result in a greater improvement in symptoms than a placebo.

“Even optimally sized water particles designed to deposit in the upper airway, where the inflammation occurs in croup, failed to bring about any improvement in the croup score,” added Scolnik. “Humidity may still have its uses in the very mild and very severe cases of croup who were not recruited in this study.”

The study also found that 36 per cent of the patients in the study had their symptoms resolve spontaneously.

The research team recommends that comforting a child who is experiencing an attack of croup helps calm them enough to ride the attack out. Otherwise, bundling them up and taking them out into colder outside air may help. More severe attacks may warrant a trip to the doctor or emergency room where steroids or inhaled epinephrine may be employed to open up the airway.

Other researchers involved in this paper include Dr. Allan Coates, Zelia Da Silva, Dr. Elana Lavine, Dr. Suzanne Schuh and Derek Stephens, all from SickKids.

This research was funded by the Physicians’ Services Incorporates Foundation of Ontario and SickKids Foundation.

SickKids Foundation is the largest non-governmental granting agency in child health in Canada. Established in 1972, the Foundation has granted over $500 million to The Hospital for Sick Children and over $65 million to researchers across the country. The mission of the Foundation is to inspire our communities to invest in health and scientific advances to improve the lives of children and their families across Canada and around the world. If you would like to make more research possible at SickKids, please make a donation .

The Hospital for Sick Children, affiliated with the University of Toronto, is Canada’s most research-intensive hospital and the largest centre dedicated to improving children’s health in the country. Its mission is to provide the best in family-centred, compassionate care, to lead in scientific and clinical advancement, and to prepare the next generation of leaders in child health. For more information, please visit www.sickkids.ca.