Filters worn in the nostrils and designed to trap inhaled pollen are useful for preventing hay fever symptoms during allergy season, according to a report from Australia.
As described in the medical journal Allergy, the filters are about 1 centimeter in diameter and fit in each nostril. They feature a tiny mesh that catches the pollen, preventing it from contacting the nasal surface.
In a study, 46 patients with ragweed and grass pollen allergy were randomly selected to wear either active or fake “placebo” nasal filters for 2 hours while visiting a park in autumn.
Use of the active filters significantly reduced hay fever symptoms at all time points compared with placebo, lead author Dr. T. J. O’Meara, from the University of Sydney, and colleagues found.
The active filter provided a significant reduction in 7 of 14 individual symptoms, including number of sneezes, runny nose, itchy nose, sniffles, itchy throat, itchy eyes, and watery eyes. In addition, a trend toward lower severity with the active filter was seen for three additional symptoms.
The authors also found that the active filter facilitated the resolution of existing symptoms.
Ninety-three percent of subjects said they would wear the filters again. However, most subjects favored wearing them in private rather than in public settings.
“This is the first reported clinical trial of nasal filters for the prevention of symptoms of Allergic rhinitis,” the investigators note. The results are encouraging, but “additional studies are required to examine the feasibility of using the nasal filters for longer periods, as would be needed for perennial allergens.”
SOURCE: Allergy, April 2005.
Revision date: July 3, 2011
Last revised: by Jorge P. Ribeiro, MD