StatPearls-/-ä 2024[Jan]; ä (ä): ä PMID33620818show ga
About 20 percent of people in the general population have an impairment of the sense of smell. Impaired olfaction leads to diminished quality of life. It can be dangerous, as environmental hazards such as the smell of natural gas or smoke may not be appreciated; the sense of taste is intimately connected with the sense of smell, and diminished taste can also result in missed indications of danger, such as spoiled or contaminated food. Furthermore, impaired olfaction may be a warning sign for common neurodegenerative disorders, such as Alzheimer's dementia and Parkinson disease. The most common causes of olfactory decline are sinonasal disease, viral infection, and nasofacial trauma. If there is a clear structural pathology in the nose or brain, treatment may be oriented toward the underlying lesion, such as functional endoscopic nasal surgery for chronic rhinosinusitis with polyposis or neurosurgical interventions for an anterior skull base tumor. In patients with damage to the olfactory epithelium and olfactory pathways due to inflammation, toxins, trauma, viral infection, or unknown causes, olfactory therapy may be appropriate. Medications such as corticosteroids for chronic rhinosinusitis and other inflammatory conditions may provide some relief from olfactory decline. Other options include sodium citrate, zinc, and vitamins, but their efficacy has not been definitively proven to date. A non-surgical and non-pharmacological approach to improve olfactory function is olfactory training, wherein patients expose themselves twice daily to different odors over the course of several months. Several studies have described the efficacy of olfactory training. In many cases, however, the studies' findings are questionable due to the absence of appropriate control groups or the lack of double-blinded experimental design. Moreover, some patients with olfactory dysfunction recover spontaneously. Up to 20% of patients with post-traumatic olfactory dysfunction and up to 60% of patients with post-infectious olfactory dysfunction demonstrate spontaneous resolution of symptoms. Additionally, younger patients, patients with relatively well-preserved olfactory function, females, and non-smokers have a good chance of a spontaneous improvement of olfactory functioning. For patients who smoke, tobacco use should be discouraged because it is associated with diminished olfactory functioning, and continued use may thwart any attempt to improve the sense of smell. Olfactory training is comparatively simple, and so far, serious side effects have not been reported. Although its precise mechanism of action and efficacy are incompletely understood, olfactory training is increasingly applied in routine care for patients with olfactory dysfunction of varying etiologies.
StatPearls-/-ä 2024 ; ä (ä): ä
