Nonallergic rhinitis.

Rhinitis is normally defined by the symptoms of nasal congestion, postnasal drainage, rhinorrhea, and sneezing. It has been associated with various pathologic changes, but can occur in the absence of any inflammation. Thus, the diagnosis is based on the clinical presentation. There are no clear-cut criteria to distinguish when rhinitis becomes chronic, but in its chronic form, it can be complex. Chronic forms of rhinitis that occur in the absence of any detectable specific IgE against relevant aeroallergens in its broadest sense can be called chronic nonallergic rhinitis. This review will concentrate on chronic nonallergic rhinitis in its various forms, discussing the epidemiology, underlying mechanisms, and its therapy.