Viral infection theory The cause of sudden deafness may be acute cochlear infection or acute cochlear vestibular labyrinthitis caused by viruses Many viruses may be associated with the disease including cytomegalovirus mumps virus rubella virus measles virus herpes simplex virus and influenza virus AB and varicella virus Many patients have a history of episodes of upper respiratory tract infection and mumps epidemic in winter and spring. The history of exposure to colds or mumps before the onset of the disease suggests that the disease is closely related to viral infections and that antiviral drugs can increase the cure rate of sudden deafness by increasing the effect of steroid therapy. Autoimmune theory Autoimmune theory is a newer pathogenic mechanism of sudden deafness Epidemiological studies suggest that some autoimmune diseases such as Cogan’s syndrome, temporal arteritis, systemic lupus erythematosus, polyarteritis nodosa, etc. are associated with sudden deafness Studies have shown that the inner ear membrane vagus has immune response, immune defense and immunoregulatory ability. In some pathological conditions, inner ear tissues can become autoantigens and trigger autoimmune reactions causing destruction of inner ear tissues and functions and consequently hearing loss. Other theories about the pathogenesis of sudden deafness include metabolic disorders, inner ear edema, allergic vascular pattern dysfunction, and other theories that have yet to be investigated.