This hypothesis is supported by a declining incidence of otosclerosis since measles vaccinations became widespread. Otosclerosis is an osseous dyscrasia limited to the temporal bone. Slowly progressive conductive hearing loss results. Frequency, as mentioned above, is thought to be decreasing secondary to measles vaccination. Otosclerosis is inherited in an autosomal dominant pattern with incomplete penetrance.
Women are two times more likely to develop the disease than are men.
Otosclerosis generally is limited to the Caucasian population. Reports implicate the measles virus by gene activation. The lesion is a pleomorphic replacement of normal bone with spongiotic or sclerotic bone. The histiologic disease progresses in stages. Bony resorption and replacement with new spongy bone characterize early lesions.