Olfactory alteration during common rhinitis component of upper respiratory tract is common observation. Smell changes leads to its own consequences on the human body affecting taste, social interactions and affecting the overall quality of life. Alterations in smell may be qualitative or quantitative and depending on the etiology, pathophysiologic mechanisms involve either the conduction part of the olfactory pathway or sensorineural component. Sensorineural component may be peripheral or central. With emergence of corona epidemic researchers are looking for reasons behind changes in smell during COVID-19 infection, so that better management can be planned for the patient involved. This article aims to present summary of pathomechanisms behind the smell changes during known inflammatory, traumatic and tumors of nasal cavity. We tried to summaries information available in literature related to the main factors responsible for olfactory sensation changes during COVID-19 infection and how this is slightly different from other known causes. Author hope that present article will serve as quick and easy reference for revision of pathophysiologic mechanisms for smell changes during various diseases involving the nasal cavity.
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