Though there are more than 100 possible causes of sudden deafness, it is rare for a specific cause to be precisely identified. Only 10 to 15 percent of patients with SSHL know what caused their loss. Normally, diagnosis is based on the patient’s medical history. Possible causes include the following:

• Infectious diseases.
• Trauma, such as a head injury.
• Abnormal tissue growth.
• Immunologic diseases such as Cogan’s syndrome.
• Toxic causes, such as snake bites.
• Circulatory problems.
• Ototoxic drugs (drugs that harm the ear).
• Neurologic causes such as multiple sclerosis.
• Relation to disorders such as Ménière’s disease.