Quick Temperature Changes Aggravate Asthma
Kids' ER visits seem to increase with heat and humidity

(HealthDay News) -- Sudden changes in temperature or humidity levels may translate into sudden changes in a child's asthma control.

Reporting in the Annals of Allergy, Asthma & Immunology, researchers found that when the heat rose by more than 10 degrees or when humidity levels jumped by more than 10 percent in a day, emergency department visits for asthmatic children went up.

"Parents need to be mindful of days when there are dramatic changes in temperature or humidity," Dr. Alan Baptist, director of the University of Michigan asthma program, in Ann Arbor, and the study's senior author, told HealthDay. "A child's asthma may flare more on those days."

But, it's not just an increase in heat and humidity that can cause asthma symptoms to flare. Cold, dry air can also trigger asthma symptoms, especially when people exercise outdoors in the winter, according to the Nemours Foundation.

Thunderstorms have also been linked to asthma exacerbations, possibly by increasing the number of fungal spores in the air, the foundation says.

About 9 million American children have asthma, according to background information in Baptist's study. Known triggers of asthma include viral infections, air pollution, tobacco smoke and pollen and other airborne allergens.

The researchers compared two years of data from emergency department admissions for asthma to what was going on with the weather at the time of admission. All of the youngsters with asthma had been seen at Children's Hospital of Michigan in Detroit between 2004 and 2005.

No link was found between changes in barometric pressure, but the researchers did find an association with heat and humidity and a rise in asthma admissions.

"A 10 percent increase in humidity two days before the admission day was associated with one additional visit to the emergency department," Baptist noted. "For temperature, an interday change of 10 degrees one day before the admission resulted in two additional visits."

He theorized that the weather changes might be triggering inflammation, and that might be what was making asthma worse. But, he said, the phenomenon needs more research.

Dr. Shean Aujla, a pediatric pulmonologist at Children's Hospital of Pittsburgh, told HealthDay that the study "brings up good discussion points, but I don't think this is going to be strong enough evidence to change practice."

"Unless a child has very severe asthma, I wouldn't say 'stay indoors' " because of the weather, Aujla said. Many kids with asthma -- even if it's persistent asthma -- might just need to use their albuterol inhaler before going out to play to head off any additional symptoms, she said.

When temperatures or humidity levels suddenly spike, keeping windows closed and using air conditioning indoors and in the car may also be helpful, according to the Nemours Foundation. In cold weather, covering a child's nose and mouth with a scarf can help keep the coldest, driest air out of the lungs.

On the Web

To learn more about asthma, visit the American College of Allergy, Asthma & Immunology.

Author: Serena Gordon

Publication Date: Sept. 30, 2010

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