Chapter 15: Allergic rhinitis.

Allergic rhinitis affects 60 million of the U.S. population, 1.4 billion of the global population, and its prevalence appears to be increasing. The duration and severity of allergic rhinitis symptoms place a substantial burden on patient's quality of life, sleep, work productivity, and activity. The health impact of allergic rhinitis is compounded by associated complications and comorbidities including asthma, otitis media, sinusitis, and nasal polyps. Allergic rhinitis symptoms result from a complex, allergen-driven mucosal inflammatory process, modulated by immunoglobulin E (IgE), and caused by interplay between resident and infiltrating inflammatory cells and a number of vasoactive and proinflammatory mediators, including cytokines. This allergic response may be characterized as three phases: IgE sensitization, allergen challenge, and elicitation of symptoms. A thorough allergic history is the best tool for the diagnosis of allergic rhinitis, the establishment of which is achieved by correlating the patient's history and physical exam with an assessment for the presence of specific IgE antibodies to relevant aeroallergens determined by skin testing or by in vitro assay. Management of allergic rhinitis includes modifying environmental exposures, implementing pharmacotherapy, and, in select cases, administering allergen-specific immunotherapy. Intranasal therapeutic options include antihistamines, anticholinergic agents, corticosteroids (aqueous or aerosol), mast cell stabilizers, saline, and brief courses of decongestants. Selection of pharmacotherapy is based on the severity and chronicity of symptoms with the most effective medications being intranasal corticosteroids and intranasal antihistamines, which can be used in combination (separately or in fixed dose) for more difficult to control allergic rhinitis.