The viruses of rubeola, rubella, mumps, varicella, and herpes zoster have been identified as causes for inner ear disorders that result in hearing and equilibrium problems. It is believed that the viruses usually enter the inner ear structures through the circulatory system or through the meningeal-subarachnoid system. When spread to the inner ear occurs via the circulatory system the stria vascularis and possibly the vascular supply to the vestibular system are invaded and structures within the endolymphatic system become primarily involved. When spread to the inner ear occurs from the meningeal-subarachnoid system via the internal meatus the neural elements in the modiolus are directly exposed to the inflammatory process which then spreads primarily in the perilymphatic system but may secondarily extend to the endolymphatic system.
Lindsay JR. Histopathology of Deafness Due to Postnatal Viral Disease. Arch Otolaryngol. 1973;98(4):258–264. doi:10.1001/archotol.1973.00780020268009