Role of the Central Nervous System in Allergic Rhinitis

Study Overview
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Brief Summary
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In order to evaluate the effects a nasal provocation on the activation of different brain regions, the investigators want to set up a clinical trial investigating the short-term effects of a nasal histamine provocation in healthy volunteers and allergic patients while in supine position under the functional MRI device in order to visualize different brain regions.

Detailed Description
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Evaluate the effects a nasal provocation on the activation of different brain regions

Official Title
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Role of the Central Nervous System in Allergic Rhinitis: Activation of Different Brain Regions After a Nasal Histamine Provocation in Healthy and Allergic Patients

Conditions
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House Dust Mite Allergy

Intervention / Treatment
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* Biological: histamine
* Biological: sham


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with a positive skin prick test to grass pollen and with pollen allergic symptoms during the pollen season OR patients with a negative skin prick test and with no allergic symptoms during the pollen season. Age > 18 and < 50 years Written informed consent Willingness to adhere to visit schedules Adequate contraceptive precautions in female patients with childbearing potential Exclusion Criteria: Current or recent (finished less than 2 years) immunotherapy against grass pollen. Systemic steroid treatment less than 6 weeks before the inclusion in the study. Nasal steroid spray, oral leukotriene antagonists or long-acting antihistamines less than 4 weeks before the inclusion. Presence of purulent secretions in nasal cavity. Severe septal deviation (septum reaching concha inferior or lateral nasal wall). Patient is pregnant or breastfeeding. Patient has any disorder of which the investigators feel at the time of evaluation for participation in the study that this may compromise the ability to give truly informed consent for participation in this study. Patient is currently enrolled in other investigational drug trial(s) or is receiving other investigational agent(s) for any other medical condition. No independent medication management in daily life or disability to perform fine motoric handling of medication Patients with asthma will be excluded. Patients suffering from claustrophobia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: patients<br>patients allergic to house dust mite receive sham solution for 5 minutes on first visit and histamine (16mg/ml) for 5 minutes on second visit | Biological: histamine<br>* administration of histamine solution (16 mg/ml) via aerosol for 5 minutes while lying under a fMRI scan<br>Biological: sham<br>* sham solution<br>|
| Sham Comparator: healthy controls<br>healthy controls receive sham solution for 5 minutes on first visit and histamine (16mg/ml) for 5 minutes on second visit | Biological: histamine<br>* administration of histamine solution (16 mg/ml) via aerosol for 5 minutes while lying under a fMRI scan<br>Biological: sham<br>* sham solution<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| brain activation | The specific aim of this study is to visualize the type and location of brain activation in healthy and allergic volunteers by a nasal provocation with histamine, using the functional MRI technology. | 5 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| nasal symptoms and Peak Nasal Inspiratory Flow | Evaluation of nasal symptoms (runny nose, blocked nose, itchy nose and post-nasal drip) and conjunctival symptoms (lacrimation and itchy eyes) will be done with VAS scores and the Peak Nasal Inspiratory Flow (PNIF) will be measured before and after both functional MRI (fMRI) scans | before and after scans |