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Researchers at Presbyterian Hospital of Dallas Study Whether Carbon Dioxide Could Effectively Treat Allergies

Tonya Khan and Gary Gross, M.D.

Researcher Tonya Khan and Dr. Gary Gross.

Click image to download hi-res file

DALLAS — Allergy researchers at Presbyterian Hospital of Dallas are studying whether short bursts of carbon dioxide in the nose could treat seasonal allergies. Called non-inhaled intranasal carbon dioxide (CO2), the treatment has been shown to block the chemical compounds that trigger migraine headaches in some people.

Researchers theorize that carbon dioxide may have the same blocking effect on the amino-acid compounds that cause seasonal allergic rhinitis, also known as hay fever. If effective, the carbon dioxide treatments could offer quick relief from allergies with fewer side effects than many over-the-counter medications.

“Initial data show carbon dioxide has the potential to be a safe and effective treatment for seasonal allergies,” said Dr. Gary Gross, an allergist on the medical staff at Presbyterian Hospital of Dallas and chief of allergy/immunology. “The CO2 may quickly treat an allergy attack, and the beneficial effects could last up to 24 hours. That could be great news for allergy sufferers.”

Seasonal allergic rhinitis is an allergic response to pollen (the male component of the plant reproductive system) or other microscopic substances. The condition, simply called “allergies” by many people, affects up to 20 percent of people in Texas and nationwide, according to Asthma and Allergy Foundation of America.

That’s about 60 million people in the United States — or 5 million Texans. It’s the sixth most common ailment nationwide, with annual medical costs estimated at $6 billion, according to the Journal of Allergy and Clinical Immunology.

Initial studies have shown that carbon dioxide begins treating allergy symptoms in less than 30 minutes and the effects of the CO2 can limit symptoms for up to 24 hours.

“One of our main objectives is to determine the effectiveness of the device,” Gross said. “We’re trying to figure whether this simple device will relieve allergy symptoms during a major pollen season such as the Metroplex has in the fall.”

The carbon dioxide is administered through a small, hand-held dispenser, though the CO2 is not inhaled. A short flow of the carbon dioxide from the dispenser allows the CO2 to enter into the nose and nasal cavities. After a few seconds, the patient then breathes the CO2 out.

“One of the intriguing elements of this study is that carbon dioxide is harmless, so the side effects to this treatment would be minimal,” Gross said. “Even if the CO2 burst is inhaled, it won’t do any harm.”

Non-inhaled intranasal carbon dioxide has been shown to be effective in preventing the onset of migraine headache. A gene-related peptide that triggers migraines is the same peptide associated with allergy symptoms.

“For allergy treatments, intranasal CO2 might stop the activation of this peptide, which could be a godsend for allergy sufferers,” said Dr. Michael Ruff, a pediatric allergist on the medical staff at Presbyterian Hospital of Dallas. The onset of the CO2’s effect is rapid, according to a preliminary study published in the Journal of Allergy and Clinical Immunology.

Two 60-second treatments administered within 5 minutes blocked hay fever symptoms for 24 hours, according to the paper. Hay fever has many of the same symptoms as a cold or other viral infection, but it can be much worse, lasting for weeks, even months, Ruff said.

“Allergies can have a significant negative impact on a person’s quality of life. People who suffer from it don’t want to go to work, they can’t sleep, their head hurts, they’re congested. It can be really devastating.”

Download a high-resolution photo of Dr. Gary Gross and researcher Tonya Kahn.
Download a high-resolution photo of the CO2 dispenser.

About Presbyterian Hospital of Dallas
Established in 1966, PHD is the flagship hospital of Presbyterian Healthcare System, a member of the faith-based, nonprofit Texas Health Resources system. US News and World Report ranks PHD, a recognized clinical program leader, providing technologically advanced care to patients, among the nation’s best hospitals in digestive disorders, orthopedics, and neurology and neurosurgery. The 866-bed facility has approximately 4,000 employees and an active medical staff of more than 1,000 physicians. For more information about PHD, visit

About Texas Health Resources
Texas Health Resources is one of the largest faith-based, nonprofit health care delivery systems in the United States and the largest in North Texas in terms of patients served. The THR system includes 13 affiliated hospitals and a medical research organization, and THR is a corporate member or partner in six additional hospitals and surgery centers. THR’s family of hospitals includes Harris Methodist Hospitals, Arlington Memorial Hospital and Presbyterian Healthcare System. For more information about Texas Health Resources, visit


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