Allergic and Nonallergic Rhinitis: Classification and Pathogenesis Part I. Allergic Rhinitis

Chronic rhinitis, although not life-threatening, substantially interferes with one's quality of life. Associated symptoms of nasal obstruction, sneezing, rhinorrhea, and anosmia afflict an estimated 40 million Americans. Directed clinical history and physical examination combined with noninvasive and routine procedures permit physicians to diagnose the myriad conditions causing rhinitis. Although the precise etiology of many of these conditions is only partially known, a practical diagnostic classification can be formulated based on clinical and laboratory findings. An understanding of the pathophysiology of allergic rhinitis as well as the other less understood entities provides the clinician with a integral foundation to implement preventative and therapeutic measures. This comprehensive review should provide the reader an opportunity to better understand and appreciate the causes and pathophysiology of chronic rhinitis. Part I of this article concentrates on IgE-mediated reactions, mediators, and drugs involved in allergic rhinitis. Part II focuses on the recent advances gained in understanding the nonallergic (non-IgE) causes of chronic rhinitis.