Inner ear infections are most often caused by viruses that inflame the delicate structures responsible for hearing and balance. Unlike the common middle ear infections that affect children, true inner ear infections (called labyrinthitis) occur deeper in the ear, where they can trigger intense vertigo, nausea, and sometimes permanent hearing changes. Less commonly, bacteria or autoimmune disorders are responsible.
Viral Infections Are the Most Common Cause
The majority of inner ear infections stem from viruses, either during an active infection or as a reactivation of a virus that’s been dormant in the body for years. The list of viruses linked to inner ear inflammation is long: herpes simplex (the cold sore virus), varicella-zoster (chickenpox and shingles), influenza, measles, mumps, rubella, Epstein-Barr virus (mono), cytomegalovirus, respiratory syncytial virus, and several others. In many cases, the inner ear inflammation develops during or shortly after an upper respiratory infection, which is why people often describe it as a complication of a bad cold or flu.
One particularly notable form is called Ramsay Hunt syndrome, caused by reactivation of the varicella-zoster virus, the same virus behind chickenpox. Years or decades after the original chickenpox infection, the virus can reawaken and attack the nerves serving the inner ear, as well as the facial nerve. About 25% of people with herpes zoster affecting the ear develop hearing and balance symptoms on top of the facial paralysis and blistering rash that characterize the condition. Roughly 6% of those who lose hearing from it never fully recover it.
Bacterial Causes and How They Reach the Inner Ear
Bacterial inner ear infections are less common than viral ones but tend to be more serious. They typically don’t start in the inner ear itself. Instead, bacteria spread inward from an untreated or severe middle ear infection, or from bacterial meningitis. The infection crosses through the thin bony barrier separating the middle ear from the inner ear, or travels along the membranes surrounding the brain. Because bacterial labyrinthitis can cause rapid, irreversible damage to hearing, it’s treated as a medical urgency.
Autoimmune Disorders Can Attack the Inner Ear
Not all inner ear inflammation comes from an infection. In autoimmune inner ear disease (AIED), the immune system mistakenly identifies inner ear cells as foreign invaders and sends antibodies to destroy them. This is a rare condition, and it comes in two forms.
In the primary form, the immune attack targets the inner ear directly for reasons that aren’t fully understood. In the secondary form, the inner ear damage is a byproduct of a body-wide autoimmune condition. About 30% of people with AIED have a systemic autoimmune disorder. Conditions linked to secondary AIED include lupus, rheumatoid arthritis, Sjögren’s syndrome, sarcoidosis, and a rare inflammatory disorder called Cogan syndrome that affects both the ears and eyes. The hallmark of AIED is progressive hearing loss in both ears over weeks to months, sometimes with episodes of vertigo, which sets it apart from the sudden, one-sided onset typical of viral labyrinthitis.
Labyrinthitis vs. Vestibular Neuritis
These two conditions are closely related and often discussed together, but they affect different structures and produce different symptoms. Understanding which one you’re dealing with matters because it determines whether your hearing is at risk.
Labyrinthitis involves inflammation of the membranous labyrinth, the fluid-filled structure deep in the inner ear that handles both balance and hearing. Because both systems are affected, labyrinthitis causes vertigo, nausea, and vomiting alongside hearing loss or ringing in the ears (tinnitus). The hearing loss is often irreversible.
Vestibular neuritis, by contrast, inflames only the vestibular nerve, the nerve that carries balance signals from the inner ear to the brain. The cochlea (the hearing organ) is spared. You get the same intense vertigo, nausea, and balance problems, but your hearing stays intact. Both conditions are most commonly triggered by the same viruses and share a similar recovery timeline.
What an Inner Ear Infection Feels Like
The onset is usually sudden and dramatic. Most people describe the room spinning violently, often accompanied by nausea and vomiting severe enough to keep them in bed. You may notice that your eyes drift involuntarily in one direction, a reflex called nystagmus that your brain produces when it receives conflicting balance signals. This acute phase can last anywhere from a few hours to several days.
After the worst vertigo passes, many people feel “off” for weeks. Walking in a straight line feels harder than it should, quick head turns trigger a wave of dizziness, and visually busy environments like grocery stores can feel overwhelming. This lingering unsteadiness happens because your brain is still recalibrating to compensate for the damaged balance signals coming from one ear.
How It’s Diagnosed
There’s no single blood test or scan that confirms an inner ear infection. Diagnosis is largely based on your symptoms, a physical exam, and ruling out other causes of vertigo like stroke or benign positional vertigo. One of the most informative tests is videonystagmography (VNG), which tracks involuntary eye movements using special goggles with a built-in camera while you sit in a dark room.
The test has three parts. First, you follow moving lights with your eyes while keeping your head still. Then your head and body are moved into different positions to see if certain movements trigger abnormal eye responses. Finally, cool and then warm water or air is directed into each ear canal separately. This temperature change normally causes a predictable pattern of eye movement. If one ear produces a weaker response than the other, it points to damage on that side. A hearing test is also performed to distinguish labyrinthitis (hearing affected) from vestibular neuritis (hearing normal).
Treatment and Recovery Timeline
In the first few days, treatment focuses on controlling the vertigo and nausea. Medications that suppress the vestibular system can take the edge off the spinning, and anti-nausea drugs help you keep food down. These are meant for short-term use only, because suppressing the vestibular system for too long actually slows the brain’s ability to adapt to the new balance situation.
Corticosteroids are frequently prescribed in the acute phase to reduce nerve inflammation, typically over a course of one to three weeks with a gradually decreasing dose. The evidence supporting their effectiveness remains mixed. Some studies show faster early recovery, while others find no significant long-term benefit compared to recovery without steroids. If a bacterial cause is identified, antibiotics are essential and may need to be given in a hospital setting.
The most important part of recovery for most people is vestibular rehabilitation, a specialized form of physical therapy that retrains the brain to process balance signals. Research suggests the optimal treatment duration is at least two months. The exercises involve specific head and eye movements, balance challenges, and walking drills that gradually push the vestibular system to compensate. Most people see significant improvement in their balance and a reduction in dizziness symptoms over this period. Full recovery from the acute vertigo often takes a few weeks, but the subtler balance issues can linger for months. Some people, particularly those with labyrinthitis, are left with permanent mild hearing loss in the affected ear.