NONALLERGIC RHINITIS - PATHOPHYSIOLOGY AND MODELS FOR STUDY

Nonallergic rhinitis is a diagnosis of exclusion which is given to pat ients who suffer perennial nasal congestion, rhinorrhea, and/or sneezi ng with no identifiable allergic etiology. Because there is still no c lear understanding of the pathophysiology, it is possible that a numbe r of different disease processes may be included within this clinicall y defined entity. This report does not attempt to present an overall d iscussion of the clinical approaches to patients with nonallergic rhin itis. Instead, an outline is presented of various research approaches which may be used in its study. A number of nasal provocation models u sing nonallergic stimuli are available for application in the laborato ry These include intranasal methacholine challenges, intranasal histam ine challenges, nasal inhalation of cold dry air, and intranasal capsa icin challenges. These models provide certain insights into mechanisms of nonallergic hyper-responsiveness. An additional approach to the st udy of nonallergic rhinitis is to examine available therapies, allowin g the clinician to evaluate various pathways of importance in the dise ase process. These approaches provide a certain understanding of this common but perplexing entity, although further study is still required .