Croup symptoms improve with cold air exposure, study finds

Key takeaways:

• Exposure to outdoor cold air improved symptoms in children with mild to moderate croup.
• The exposure took place in the 30 minutes between the administration and onset of effect of steroids.

Croup symptoms improved when children were exposed to 30 minutes of outdoor cold air in addition to receiving a steroid, according to the results of a randomized controlled trial published in Pediatrics.

A common cause of acute upper airway obstruction in children, croup is characterized by the abrupt onset of a distinctive, seal-like barking cough, the researchers wrote.

In recent years, studies have reported “compelling evidence” that the omicron variant of SARS-CoV-2 could cause croup, with croup-related hospitalizations increasing during the omicron wave in early 2022.

“Arrival of children with croup in emergency departments (EDs) is frequent during the croup seasonal peaks,” Johan N. Siebert, MD, a professor of medicine at the University of Geneva and pediatric emergency medicine physician at Geneva Children’s Hospital, told Healio.

“Croup represents the leading cause of ED visits for upper airway obstruction in pediatrics,” Siebert said “On arrival, parents frequently report an improvement in symptoms during the journey with exposure to outdoor cold air. In the absence of corroborating evidence to date, our research team decided to carry out this trial, which was fairly simple to set up.”

Siebert and colleagues enrolled 118 children between November 2016 and May 2021with an average age of 32 months who had mild to moderate croup and randomly assigned them in a 1:1 ratio to spend 30 minutes in outdoor cold air — with blankets — or indoors at room temperature for 30 minutes after they were administered a single dose of oral dexamethasone.

Nearly half of the cold and outdoor group — 49.2% — showed a decrease in symptoms after 30 minutes compared with 23.7% of the indoor group.

“These results didn't surprise us, but rather excited us, as they were in line with what the parents reported for years, and legitimize a simple, common-sense intervention to be carried out before the child arrives in EDs, perhaps limiting the influx, or to be easily implemented in EDs if conditions allow,” Siebert said.

The authors suggested that the easy-to-perform intervention could offer some immediate relief to children with croup.

“This is an interesting randomized trial that supports a common practice that pediatricians and families have long used with good anecdotal effects,” Siebert said. “There is now evidence that initial exposure to outdoor cold air plays a role in improving croup symptoms, particularly in moderate cases, as an adjunct to oral dexamethasone.”