Labyrinthitis is an inflammatory disorder of the inner ear, or labyrinth. Clinically, this condition produces disturbances of balance and hearing to varying degrees and may affect one or both ears. Bacteria or viruses can cause acute inflammation of the labyrinth in conjunction with either local or systemic infections. Autoimmune processes may also cause labyrinthitis. Vascular ischemia may result in acute labyrinthine dysfunction that mimics labyrinthitis".

Source : Medscape

It can be triggered by viral or bacterial infections, as well as by air travel and diving (presumably due to air-pressure variations). It usually fully resolves after six weeks or so. It's thought to affect around 35 million people each year.

The exact mechanism which leads to the condition has not been identified.

More info UK NHS

Also see: Ménière’s diseaseplugin-autotooltip__plain plugin-autotooltip_bigMénière’s disease

"Ménière’s disease is a disorder of the inner ear that causes severe dizziness (vertigo), ringing in the ears (tinnitus), hearing loss, and a feeling of fullness or congestion in the ear. Ménière’s disease usually affects only one ear." and Motion sicknessplugin-autotooltip__plain plugin-autotooltip_bigMotion sickness

Dizziness and nausea is frequently caused by unusual physical motion (or perceived motion) - e.g. air sickness, sea sickness, car sickness, VR simulation sickness etc etc.

There are three commonly-documented versions :

* Caused by motion that is felt but not seen