Thoughts on the pathophysiology of nonallergic rhinitis

Abstract

Nonallergic noninfectious rhinitis is a diagnosis by exclusion, meaning that a number of poorly defined nasal conditions that have in common allergy and infection as a cause of the rhinitis have been excluded. The etiology of some subgroups of nonallergic noninfectious rhinitis, like nonallergic rhinitis with eosinophilia (NARES) and drug-induced rhinitis, are quite well defined, but in the majority of the patients, the etiology and pathophysiology are unknown. These patients are classified as idiopathic rhinitis patients. A careful determination of the intensity of the symptoms combined with modern diagnostic tools enables us to discriminate idiopathic rhinitis patients from normal controls. This review discusses the possible pathophysicologic mechanisms of nonallergic noninfectious rhinitis, with emphasis on idiopathic rhinitis.

Allergic Rhinitis and its Impact on Asthma (ARIA) 2008*

“…Persistent nonallergic rhinitis with eosinophilia is a heterogeneous syndrome consisting of at least two subgroups: NARES and aspirin hypersensitivity (30).…”

“…Several nonallergic conditions can cause similar symptoms: infections, hormonal imbalance, physical agents, anatomical anomalies and the use of certain drugs (30). Rhinitis is therefore classified as shown in Table 2 (1).…”

Important research questions in allergy and related diseases: nonallergic rhinitis: a GA2LEN paper

“…Several nonallergic conditions can cause similar symptoms: infections, hormonal imbalance, physical and chemical agents, anatomical anomalies and the use of certain drugs (3). However, many patients have symptoms that mimick allergic rhinitis, with no definite causal factor and with a lack of demonstrated IgE-mediated allergy by skin prick tests and allergen-specific serum IgE (4).…”

Role of inflammation in non-allergic rhinitis

“…Indeed, some authors have suggested that there is a large subgroup of patients with symptomatic NAR in the absence of any inflammatory changes in the nasal mucosa. In these patients, it is not possible to identify an inflammatory cell infiltrate such us in hormonal rhinitis, damage to sympathetic nerves as in Horner's syndrome or overuse of topical-adrenergic agonists/ nasal decongestants ("rhinitis medicamentosa") (22) . On the other hand, several authors have demonstrated that most patients with NAR have some degree of inflammation suggesting that nasal cytological evaluation may aid in identifying forms of NAR in which inflammation is involved and in classifying this latter according to the inflammatory cell type (3) .…”