Olfaction and anosmia in rhinosinusitis.

Olfactory disorders can cause serious consequences from the inability to detect many olfactory warning signals (eg, smoke, spoiled food, and gas leaks) and can significantly impact nutritional status, eating satisfaction, and many other issues related to quality of life. More than 200,000 people a year seek treatment for impaired olfactory ability, and available evidence suggests this figure is a significant underestimate of those affected. Rhinitis and rhinosinusitis are the primary etiologies for olfactory loss or distortion among patients presenting to chemosensory clinics, and they are among the most common chronic medical conditions in the United States, affecting an estimated 33 million people. Both allergic and nonallergic rhinitis/rhinosinusitis can result in diminished, distorted, or absent olfactory ability. Current therapies are only partially or transiently effective in reversing olfactory loss. The underlying mechanisms by which rhinitis/rhinosinusitis impact olfactory ability are likely to be multifactorial and might include altered air flow and odor deposition, changes in mucus composition, and effects of inflammatory mediators on receptor cell differentiation, maturation, or function.