Chapter 5: Allergic rhinitis.

Rhinitis is a symptomatic inflammatory disorder of the nose with different causes such as allergic, nonallergic, infectious, hormonal, drug induced, and occupational and from conditions such as sarcoidosis and necrotizing antineutrophil cytoplasmic antibodies positive (Wegener's) granulomatosis. Allergic rhinitis affects up to 40% of the population and results in nasal (ocular, soft palate, and inner ear) itching, congestion, sneezing, and clear rhinorrhea. Allergic rhinitis causes extranasal untoward effects including decreased quality of life, decreased sleep quality, obstructive sleep apnea, absenteeism from work and school, and impaired performance at work and school termed "presenteeism." The nasal mucosa is extremely vascular and changes in blood supply can lead to obstruction. Parasympathetic stimulation promotes an increase in nasal cavity resistance and nasal gland secretion. Sympathetic stimulation leads to vasoconstriction and consequent decrease in nasal cavity resistance. The nasal mucosa also contains noradrenergic noncholinergic system, but the contribution to clinical symptoms of neuropeptides such as substance P remains unclear. Management of allergic rhinitis combines allergen avoidance measures with pharmacotherapy, allergen immunotherapy, and education. Medications used for the treatment of allergic rhinitis can be administered intranasally or orally and include oral and intranasal H(1)-receptor antagonists (antihistamines), intranasal and systemic corticosteroids, intranasal anticholinergic agents, and leukotriene receptor antagonists. For intermittent mild allergic rhinitis, an oral or intranasal antihistamine is recommended. In individuals with persistent moderate/severe allergic rhinitis, an intranasal corticosteroid is preferred. When used in combination, an intranasal H(1)-receptor antagonist and a nasal steroid provide greater symptomatic relief than monotherapy. Allergen immunotherapy is the only disease-modifying intervention available.