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Test produced symptoms of allergic rhinitis in grass-allergic participants

When exposed to grass pollen in a controlled setting, participants with grass allergies exhibited symptoms of allergic rhinitis, according to study data.

Anne K. Ellis, MD, MSc, of Queen’s University in Ontario, and colleagues conducted two 3-hour sessions of rye grass pollen exposure on 39 participants with grass allergies and eight nonatopic participants in an environmental exposure unit (EEU). The unit, developed at Kingston General Hospital and Queen’s University, is a specially designed facility that pumps controlled amounts of pollen into the room.

Anne K. Ellis

Participants were randomly separated into two groups and attended sessions on consecutive days. Within the room, the groups were exposed to two different levels of target grass pollen concentration, either a lower (2,500 grains/m³; n=19) or higher concentration (3,500 grains/m³; n=20).

On day 1, the mean total symptom score (TSS) for participants in the higher concentration was 18.9, the total nasal symptom score (TNSS) was 9.7, and the peak nasal inspiratory flow (PNIF) was 68.1 L/minute. Participants in the lower concentration group had a mean TSS of 13.3, a TNSS of 7.6 and a PNIF of 82.4 L/minute.

On day 2 of grass pollen exposure, the researchers did not observe any significantly altered maximal scores of TSS and TNSS in either group; however, the occurrence of symptoms such as sneezing, nasal itching and red/burning eyes was more rapid than on day 1.

“This study confirms that, similar to ragweed pollen, grass pollen dispersed in the EEU can be effectively used to elicit [allergic rhinitis] symptoms in grass-allergic individuals,” Ellis and colleagues wrote.

Disclosure: See the study for a full list of relevant financial disclosures.