Relief for seasonal allergic rhinitis sufferers

The results of a new Creighton University study may soon spell relief for some of the estimated 40 million Americans who suffer from seasonal allergic rhinitis (SAR) caused by pollens such as grass and ragweed.

According to Creighton (Cray-ton) researchers, noninhaled, intranasal carbon dioxide (CO2) may offer a new, effective and safe treatment for many SAR sufferers. The study will be reported in an upcoming issue of the Journal of Allergy & Clinical Immunology .

“These findings indicate that noninhaled, intranasal carbon dioxide is very promising as a safe and effective treatment to provide rapid relief for seasonal allergic rhinitis. With the exception of a burning/stinging sensation when the carbon dioxide is first administered, there appears to be no significant side effects with this technique.

“It could be a good alternative for people who don't want to take intranasal steroids,” said Thomas B. Casale, M.D., principal investigator and chief of Creighton School of Medicine's Division of Allergy/Immunology.

Currently, there are no treatments available that provide truly rapid relief of SAR symptoms and can be used safely long-term, he added.

In the Creighton study, patients receiving CO2 reported a significant and rapid improvement in congestion, sneezing and other nasal symptoms – within 10 minutes and lasting at least 24 hours – over those taking a placebo (plain air). The CO2 group also reported some, although not statistically significant, improvement in non-nasal symptoms such as watery and itchy eyes.

Within 30 minutes of treatment, 50 percent of those taking CO2 reported more than a 50 percent improvement in nasal symptoms, compared to 27.6 percent of the placebo group.

The Creighton study involved 89 subjects, 18 to 75 years of age, who had at least a two-year history of seasonal allergies requiring pharmacotherapy. Sixty received CO2 and 29 received plain air.

The patients took the gases intranasally twice – once for each nostril – within an interval of less than five minutes for a total dose of about 1,200 milliliters. They avoided inhaling the gas by breathing through the mouth, allowing the gas to flow in one nostril, pass through the nose and sinus cavities, and pass out the other nostril.

The use of intranasal noninhaled CO2 has already proven effective in treating migraines, although it is not yet approved by the U.S. Food and Drug Administration for that use. Allergic rhinitis is triggered by some of the same mechanisms as migraines.

Casale noted that, despite currently available treatments, a significant proportion of patients with allergic rhinitis continue to suffer symptoms that impair their quality of life and can lead to other conditions such as asthma. The medical costs associated with SAR are estimated at $6 billion annually in the United States alone, he said.