ABSTRACT
Nonallergic rhinitis (NAR) occurs in 17 million Americans, according to The National Rhinitis Classification Task Force (1). NAR is a diverse syndrome that encompasses a complex and broad variety of disorders (2,3). Approximately half of rhinitis patients in otolaryngology clinics may have allergic rhinitis (AR), and the other half NAR. This discrimination is based on the presence of nasal symptoms with or without positive allergy skin tests (AST), radioimmunallergosorbant test variants of this test, or allergen nasal provocations (4,5). About half of AR patients also complain of nonallergic symptoms that are induced by irritants (‘‘irritant rhinitis’’) (6). This overlap demonstrates the difficulties of describing syndromes based solely on their clinical or symptomatic characteristics without regard to underlying pathophysiological mechanisms. Our purpose is to outline the many conditions that fall under the rubric of ‘‘persistent rhinitis without atopy.’’ We will use the all-encompassing term of NAR, even though some of the conditions may extend into the sinuses [‘‘rhinosinusitis’’ (7,8)], or be systemic diseases with nasal manifestations. A critical reason for the attention to mechanisms is that targeted treatments can be designed to act against specific mechanisms, but can be very difficult to develop when dealing with a symptom complex.
