It is necessary to keep in mind that the etiology of immune-mediated SNHL involves various causes ranging from vasculitis to type II collagen-related disorders. 2. Clinical cases believed to involve sympathetic labyrinthitis are extremely rare. 3. The mechanism of occurrence of SNHL associated with autoimmune diseases should probably not be attributed to immunologic abnormalities in all cases. 4. Of the cases of SNHL associated with autoimmune diseases, only those associated with aortitis syndrome (Takayasu disease) are steroid-responsive. 5. The autoimmune SNHL described by McCabe is believed to be closely related to Cogan's syndrome. On the other hand, steroid-responsive SNHL includes three types: a systemic type associated with aortitis syndrome, a localized type not associated with any known autoimmune disease, and a syphilitic type. It is thought that sex differences and differences in such findings as the caloric response between the two disease entities is due to interracial differences in the degree of vasculitis.
