What is "anosmia"

Anosmia \A*nos"mi*a\, n. [NL., fr. Gr. 'an priv. + ? smell.] (Med.) Loss of the sense of smell.

"loss of sense of smell," 1811, Modern Latin, from Greek an-, privative prefix (see an- (1)), + osme "smell" (Doric odme), from *odsme, cognate with Latin odor (see odor) + abstract noun ending -ia.

n. inability#English to smell; the inability to perceive odors.

n. absence of the sense of smell (as by damage to olfactory nasal tissue or the olfactory nerve or by obstruction of the nasal passages)

Anosmia is the inability to perceive odor or a lack of functioning olfaction—the loss of the sense of smell. Anosmia may be temporary, but some anosmia (including traumatic anosmia) can be permanent. Anosmia is due to a number of factors, including an inflammation of the nasal mucosa, blockage of nasal passages or a destruction of one temporal lobe. Inflammation is due to chronic mucosa changes in the paranasal sinus lining and the middle and superior turbinates.

When anosmia is caused by inflammatory changes in the nasal passageways, it is treated simply by reducing inflammation. It can be caused by chronic meningitis and neurosyphilis that would increase intracranial pressure over a long period of time, and in some cases by ciliopathy including ciliopathy due to primary ciliary dyskinesia (Kartagener syndrome, Afzelius' syndrome or Siewert's syndrome).

Many patients may experience unilateral anosmia, often as a result of minor head trauma. This type of anosmia is normally only detected if both of the nostrils are tested separately. Using this method of testing each nostril separately will often show a reduced or even completely absent sense of smell in either one nostril or both, something which is often not revealed if both nostrils are simultaneously tested.

A related term, hyposmia, refers to a decreased ability to smell, while hyperosmia refers to an increased ability to smell. Some people may be anosmic for one particular odor. This is known as "specific anosmia". The absence of the sense of smell from birth is called congenital anosmia.