What is nasal hyperreactivity?

Abstract

One definition of nasal hyperreactivity (NHR) is: "the induction of one or more nasal symptoms like rhinorrhea, sneezing/itch, or obstruction upon encounter of environmental stimuli, such as cigarette smoke, temperature/humidity changes, strong odours/fragrances, and other irritants". NHR may feature in every kind of rhinitis, irrespective of aetiology, including coryza (due to an infection), nonallergenic rhinitis (NAR) or allergic rhinitis (AR). Currently, it appears that chemical (irritant) causes for NHR (smoking, perfumes, cleaning materials) produce the same generalised disturbance of the mucosa lining the nose and upper airways as physical causes, such as changing temperature, exercising, being under stress or in humid conditions. The situation thus appears to resemble that found in conditions producing hyperresponsiveness of the bronchi, such as asthma or COPD (chronic obstructive pulmonary disease), where both chemical and physical triggers produce identical mucosal alterations. Indeed, most cases of untreated airway disease, affecting all portions of the tract (rhinitis and asthma), are said to feature mucosae that are hyperresponsive. In this chapter, NHR is presented.