What causes tinnitus?

Although the exact mechanism underlying tinnitus is unknown, it is likely that there are many related factors. Tinnitus usually, but not always, has to do with an abnormality of the hearing or neural system.
There are a number of causes linked with tinnitus including:

• Disorders in the outer ear, such as ear wax, a hair touching the eardrum, a foreign body or a perforated eardrum
• Disorders in the middle ear, such as negative pressure from eustachian tube dysfunction, fluid, infection, otosclerosis, allergies or benign tumors
• Disorders in the inner ear, such as sensorineural hearing loss due to noise exposure, aging, inner ear infection or Meniere's disease often accompanied by hearing loss and dizziness

Tinnitus also can temporarily result from certain medications, such as:

• Anti-inflammatories such as aspirin, ibuprofen, nonsteroidal anti-inflammatories and quinine
• Sedatives
• Antidepressants
• Certain antibiotics and chemotherapeutic agents

Other causes include:

• Systemic disorders such as high or low blood pressure, anemia, diabetes, thyroid dysfunction, glucose metabolism abnormalities, vascular disorders, growth on jugular vein, acoustic tumors and head or neck aneurysms
• Non-auditory disorders such as trauma to the head or neck, temporomandibular (jaw joint) disorders and neck misalignment

Current research suggests that even though tinnitus may initially be caused by an injury to the ear, ultimately an auditory pattern is established in the brain. Therefore, many treatment approaches are directed at the brain, not the ear.
Although the majority of tinnitus sufferers also have hearing loss, the presence of tinnitus does not indicate that one is losing hearing.

Surce: http://www.ucsfhealth.org/