Allergic rhinitis is a common disorder that results from a complex interaction of environmental and genetic causes. This disorder has a tremendous impact on the quality of life and on health care expenditures, as evidenced by a large loss of worker productivity. Care must be taken to promptly diagnose patients with this condition, evaluate them for associated conditions, and begin appropriate management to reduce its impact on the individual and the health care system. Allergic rhinitis represents only a component of the spectrum of inflammatory diseases involving the unified airway.