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In the meantime, you can enjoy access to all the latest news, events and resources for different therapy areas on our website.Nasal and ocular responses after specific and nonspecific nasal challenges in seasonal allergic rhinitis
Tomljenovic D, Baudoin T, Megla ZB, Vagic D, Hellings P, Kalogjera L. Ann Allergy Asthma Immunol 2016; 116(3): 199–205
Triggers of seasonal allergic rhinitis
Patients with seasonal allergic rhinitis (SAR) may suffer symptoms due to both exposure to airborne allergens and non-specific nasal hyper-responsiveness. 1
Airborne allergens may trigger SAR symptoms by two main mechanisms: 1
- Triggering Immunoglobulin E-mediated immune responses in the nasal mucosa – resulting in sneezing, itching, nasal rhinorrhea and congestion.
- Stimulation of sensory nerves – releasing neuropeptides and neurokinins and causing lacrimation, sneezing, coughing and itch.
However, the mechanisms by which non-specific challenges trigger SAR are not fully understood. This study, reported in Annals of Allergy, Asthma & Immunology investigated the effects of different nasal challenges on nasal and ocular symptoms of SAR. 1
Non-specific triggers of SAR include exposure to irritants, and environmental factors such as changes in temperature or humidity. 1
Sequential challenge of primed patients
A total of 25 patients with seasonal allergies to ragweed and/or grass pollen were primed by nasal administration of lyophilized allergen out of pollen season.1 Each patient received a skin prick test to establish if grass or ragweed allergen should be used for the specific challenge. On the following day, patients were challenged by non-specific stimuli: nasal administration of histamine on Day 2 and hypertonic saline on Day 3. 1
Tear fluids were collected bilaterally using Schirmer strips 5 minutes after each nasal challenge and nasal lavage was collected 15 minutes after each nasal challenge. Patient-reported evaluation of nasal and ocular symptoms (visual analogue scale questionnaire) was conducted before and 15 minutes after nasal challenge. 1
Response to specific and non-specific challenges
Tryptase concentration in nasal lavage following specific (allergen) challenge correlated with aggregated ocular symptom scores (visual analog scale; ocular itch and lacrimation). 1
Non-specific nasal challenge (histamine, hypertonic saline) triggered ocular symptoms characteristic of neurogenic inflammation (eye itch, nasal burning, and elevated levels of neurokinin substance P in tears). Concentrations of neurokinin substance P in tears after histamine or hypertonic saline challenge were similar, indicating that different non-specific stimuli resulted in similar neurogenic inflammatory responses. 1
Conclusions
The authors conclude that priming with a single low-dose allergen challenge enhances the nasoocular reflex to non-specific challenges. Following these non-allergic stimuli, ocular symptoms, were at least the same or higher if patients were primed with a low dose of allergen. 1
Report on: Nasal and ocular responses after specific and nonspecific nasal challenges in seasonal allergic rhinitis. Tomljenovic D, Baudoin T, Megla ZB, Vagic D, Hellings P, Kalogjera L. Nasal and ocular responses after specific and nonspecific nasal challenges in seasonal allergic rhinitis. Ann Allergy Asthma Immunol 2016; 116(3): 199–205.
