Otosclerosis is a condition of the middle ear and mainly affects the tiny stirrup (stapes) bone. It causes gradual hearing loss.

Otosclerosis is a common cause of hearing loss. It is caused by a problem with the tiny bones (ossicles) which transmit vibrations through the middle ear so we can hear sound. Usually both ears are affected in otosclerosis but sometimes only one ear is affected.

Who gets otosclerosis and what causes it?

Otosclerosis affects about 1 or 2 in 100 people in the UK.

  • It usually first develops between the ages of 15-35 years but sometimes develops in younger children.
  • Women are affected twice as often as men.
  • Pregnancy is not a cause but may make the condition worse, so symptoms are commonly first noticed during pregnancy.

Nobody actually knows why otosclerosis happens. However, what is known is that otosclerosis is not caused or worsened by listening to loud music or working in a loud environment.

Otosclerosis happens because there is abnormal bone formation in one of the tiny bones in the middle ear. It is not clear why this happens but it is likely to be caused by a combination of various factors:

  • Hereditary (genetic) factors.
  • Complications from having had a virus.
  • Possible effect of low fluoride levels.

What happens long-term?

Generally the hearing loss progresses over time, although this may be very slow. If it becomes bad enough for you to need an operation, that is usually very successful at resolving the hearing problems and other symptoms.

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Dr Jan Sambrook
Peer Reviewer:
Dr Helen Huins
Document ID:
4587 (v43)
Last Checked:
10 May 2017
Next Review:
29 June 2020

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.