Anosmia

Anosmia
Other names	Loss of smell, smell blindness,[1] odor blindness
Inflamed nasal mucosa causing anosmia
Pronunciation	/ænˈɒzmiə/
Specialty	Otorhinolaryngology
Types	Partial, total[2]

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]

Anosmia can be due to a number of factors, including inflammation of the nasal mucosa, blockage of nasal passages, or destruction of temporal lobular tissue.^[4] Anosmia stemming from sinus inflammation is due to chronic mucosal changes in the lining of the paranasal sinus and in the middle and superior turbinates.^[5][6]

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-Latin anosmia, 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]

Anosmia is a common symptom of COVID-19 and can persist as long COVID.^[13]