Anosmia, also known as smell blindness, is the loss of the ability to detect one or more smells.[1][2] Anosmia may be temporary or permanent.[3] It differs from hyposmia, which is a decreased sensitivity to some or all smells.[2]
When anosmia is caused by inflammatory changes in the nasal passageways, it is treated simply by reducing inflammation.[7][8] It can be caused by chronic meningitis and neurosyphilis that would increase intracranial pressure over a long period of time,[9] and, in some cases, by ciliopathy,[10] including ciliopathy due to primary ciliary dyskinesia.[11]
The term derives from the Neo-Latinanosmia, based on Ancient Greek ἀν- (an-) + ὀσμή (osmḗ 'smell'; another related term, hyperosmia, refers to an increased ability to smell). Some people may be anosmic for one particular odor, a condition known as "specific anosmia". The absence of the sense of smell from birth is known as congenital anosmia.[12]
In the United States, 3% of people aged over 40 are affected by anosmia.[3]