Nasal Filter: A New Tool in the Fight Against Hay Fever?

By Laura Newman

July 20, 2015

NEW YORK (Reuters Health) - People plagued by seasonal allergic rhinitis might try a new nasal filter to prevent symptoms before they start, the Danish researchers who designed it suggest.

Dr. Torben Sigsgaard of Aarhus University Hospital in Denmark, senior author of the paper, called the filter "an easy and simple remediation to prevent allergen exposure during the pollen season for persons suffering from allergic hay fever."

"The nasal filters are preventing attacks in already sensitized persons," he told Reuters Health by email.

The filters have been cleared by the U.S. Food and Drug Administration for patients aged 6 years and older, according to Paul Kenney, a medical student who led the study. Kenney is part owner of the company, Rhinix, that manufactures the filters.

For their randomized crossover trial, conducted over two days in June 2014 during the main grass pollen season, the research team enrolled 65 adults with documented grass allergy.

As reported online June 30 in the Journal of Allergy and Clinical Immunology, the primary outcome was a total nasal symptom score (TNSS), which measured a blocked nose, runny nose, nasal itching, and sneezing.

Both the nasal filter and a placebo device, available in three sizes, were inserted at the base of the nose the same way.

In supplemental material available online with the paper, the authors explain, "The nasal filter consists of a membrane that removes particles by means of interception and impaction. The membrane is placed in each nostril's anterior vestibule and kept in place by a copolymer frame. In the placebo filters the membrane was omitted from the frame."

If people needed to remove the device because they needed to sneeze or blow their nose, they were instructed to take a tissue, remove the device, place it in the tissue, and fold it without looking at its contents. The participants were observed throughout the day.

Participants arrived at the lab about 9:00 am, started wearing the masks about 9:30, and researchers started assessments at 11:30. Participants left about 5:00 pm each day. Participant who wore the study mask on day 1 wore the placebo mask on day 2, and vice versa.

Overall, use of the nasal filter led to median relative reductions of 40% for daily TNSS, 43% for maximum TNSS, 83% for daily sneezing, 75% for watery eyes, and 53% for daily runny nose, compared with placebo.

The researchers noted that no difference in symptom severity occurred between the nasal filter group on day 1 and the nasal filter group on day 2, even though pollen levels on day 2 were almost three times as high as on day 1.

As for adverse events, only three individuals reported difficulty, including a mild burning sensation in the placebo group and a moderate nasal itch with the filter group.

"Even though most subjects noticed wearing the devices at one point during the study (57 for placebo and 61 for the nasal filter), about two thirds of the subjects indicated that they were unaware of wearing the devices at each time point, and very few reported increased resistance to breathing," the authors wrote.

Dr. Sigsgaard explained, "They are intended to be used for the entire season of the person. This could be months if the person has more seasonal allergies."

Kenney, the medical student who developed and patented the filters, said, "One of the most important strategies for getting the most benefit . . . will be educating patients on when to insert the nasal filters."

Dr. Mark S. Dykewicz, chief of the Section on Allergy and Immunology at Saint Louis School of Medicine, in St. Louis, Missouri, questioned whether this study was adequate for recommending long-term use. "You really need to assess this approach for a longer period of use," he said in a telephone interview with Reuters Health. "The duration of use was only two days. In addition, you need to determine patient tolerance and preferences for ongoing use of the device versus other available treatments."

Dr. Dykewicz acknowledged that the current study was not designed to answer questions on the overall usability of nasal filters in subjects' everyday lives. However, he thought that the practical difficulty in terms of removing the device if you have mucus in your nose might be problematic. He also thought that the fact there were no significant differences on day 1 raise issues.

Paul Kenney is the founder and part owner of Rhinix, and holds a patent, and stock options with the company, Rhinix ApS, Aarhus, Denmark. The rest of the authors declared no relevant conflicts of interest.


J Allergy Clin Immunol 2015.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.