Nonallergic rhinitis with eosinophilia syndrome and related disorders.

NARES is a clinical syndrome consisting of symptoms consistent with AR in which an absence of atopy has been demonstrated by allergen skin testing, with nasal cytology analysis showing greater than 20% eosinophils. Anosmia is a prominent feature not shared with AR. The pathophysiology of NARES is poorly understood, but a key component involves a self-perpetuating, chronic eosinophilic nasal inflammation with development of nasal micropolyposis and polyposis. Mast cells likely play an important role as well. NARES is a risk factor for the development of nasal polyposis and aspirin sensitivity, as well as obstructive sleep apnea. Treatment consists mainly of intranasal corticosteroids with or without the addition of second-generation antihistamines and/or LT receptor antagonists as an adjuvant.