Intranasal CO2 for treatment of allergic rhinitis

Noninhaled intranasal carbon dioxide (CO2) has been shown to be effective for treatment of migraine headache. Migraine headache pathophysiology is associated with release of calcitonin gene-related peptide, also implicated in allergic rhinitis. Intranasal CO2 inhibits the release of calcitonin gene-related peptide.

In a single-center RCT, two 60-second intranasal CO 2 treatments resulted in rapid (10 minutes) and sustained (24 hours) relief of seasonal allergic rhinitis symptoms. The authors concluded that, intranasal CO2 has a potential as a safe and effective treatment for seasonal allergic rhinitis.

However, the newer studies, from 2011, were less promising: Intranasal CO2 spray helps allergic rhinitis symptoms but only for 4 hours and at the cost of relatively poor tolerance http://goo.gl/b0wwt

References:
Intranasal noninhaled carbon dioxide for the symptomatic treatment of seasonal allergic rhinitis.
Casale TB, Romero FA, Spierings EL. J Allergy Clin Immunol. Volume 121, Issue 1, Pages 105-109 (January 2008).
Intranasal CO2 spray helps allergic rhinitis symptoms but only for 4 hours and at the cost of relatively poor tolerance http://goo.gl/b0wwt
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Comments from Twitter:

@AllergyNet (Dr John Weiner): Tens of millions of people squirting CO2 into the air? I don't think so @Reuters_Health Can CO2 help with hayfever reut.rs/nmylh5




Treatment Options for Allergic Rhinitis (click to enlarge the image).