Otosclerosis is the most common cause of middle ear hearing loss in young adults. It typically begins in early to mid-adulthood. It is more common in women than in men. The condition may affect one or both ears. Risks for this condition include pregnancy and a family history of hearing loss. Caucasians are more likely to develop this condition than people of other races.

The disease may remain confined to one particular ear; the other ear may become involved later. Hearing loss typically becomes apparent when the loss reaches 25-30 dB and the patient has difficulty understanding speech. Patients characteristically have low-volume (soft) speech because they hear their own voices by bone conduction and consequently talk quietly. The ability to hear better in noisy surroundings (paracusis) during the early stages of hearing impairment is highly suggestive of otosclerosis. Tinnitus is a common complaint and may be an indication of sensorineural degeneration.