Diagnosing an inner ear infection is largely a clinical process, meaning doctors rely heavily on your symptoms, your history, and a series of physical exam maneuvers rather than a single definitive lab test. There’s no throat swab or blood draw that confirms it the way you’d diagnose strep throat. Instead, the goal is to match your specific pattern of symptoms to an inner ear cause while ruling out more dangerous possibilities like stroke.
What Doctors Look for First
The most important diagnostic clue is your symptom profile. Inner ear infections (labyrinthitis and vestibular neuritis) cause severe, persistent vertigo that lasts hours to days, along with nausea, vomiting, and difficulty walking. This isn’t the brief, positional spinning you get from rolling over in bed. It’s constant, even when you’re sitting still.
The key distinction between the two main types of inner ear infection is hearing. Labyrinthitis involves inflammation of both the balance and hearing structures, so it typically causes hearing loss or ringing in one ear alongside the vertigo. Vestibular neuritis affects only the balance nerve, leaving hearing completely intact. Your doctor will ask specifically about changes in hearing to narrow down which condition you have. The hearing loss in labyrinthitis is often permanent, which is one reason getting evaluated promptly matters.
Physical Exam Maneuvers
Your doctor will likely start by checking whether your vertigo is caused by something simpler: benign paroxysmal positional vertigo, or BPPV. The Dix-Hallpike maneuver is the standard test for this. A provider moves your head into specific positions while watching your eyes for involuntary flickering movements called nystagmus. If the test triggers a brief burst of nystagmus that fades within a minute, you likely have BPPV rather than an infection. A negative result means something else is causing your symptoms.
For persistent vertigo, many emergency departments and specialists use an exam called HINTS, which stands for Head Impulse, Nystagmus, and Test of Skew. It involves three quick checks:
- Head impulse test: The doctor turns your head quickly to one side while you focus on their nose. In an inner ear infection, your eyes briefly lose their target and snap back, a “corrective saccade” that tells the doctor your inner ear on that side isn’t sending proper balance signals.
- Nystagmus direction: The doctor watches whether your involuntary eye movements always beat in the same direction, regardless of where you look. In an inner ear infection, the direction stays consistent. If it changes when you look different ways, that’s a red flag for a brain-related cause.
- Test of skew: The doctor covers and uncovers each eye, watching for a vertical correction where one eye drifts up or down. A normal (negative) result here supports an inner ear diagnosis. An abnormal result raises concern about stroke.
When all three components point to a peripheral (inner ear) cause, the HINTS exam is remarkably accurate, even outperforming early MRI in some stroke studies. This is one of the most important tools doctors have for distinguishing inner ear infections from strokes, which can produce nearly identical symptoms.
Hearing Tests
If your doctor suspects labyrinthitis, you’ll likely undergo a hearing test called pure tone audiometry. You sit in a soundproof booth wearing headphones and respond to tones played at different pitches and volumes. In labyrinthitis, this typically reveals hearing loss on one side only. There’s no single predictable pattern to the loss; it can affect low frequencies, high frequencies, or both. The test helps confirm that the cochlea (the hearing part of the inner ear) is involved and establishes a baseline so doctors can track whether your hearing recovers.
Vestibular Function Testing
When symptoms are unclear or don’t resolve as expected, your doctor may order videonystagmography, commonly called VNG. This is the most widely used test for evaluating the inner ear’s balance system. You wear special goggles with a built-in camera that records your eye movements through three rounds of testing.
First, you track moving and stationary lights without moving your head. Then, the examiner moves your head and body into different positions to see if specific postures trigger abnormal eye movements. Finally, the caloric test: warm and cool water or air is gently delivered into each ear canal, one at a time. The temperature change stimulates the balance organ in each ear independently, which lets the examiner compare how well each side is functioning. If one ear responds significantly less than the other, it confirms that side has vestibular damage. This part of the test can provoke vertigo, but the sensation is temporary.
A video head impulse test (vHIT) is a more precise, technology-assisted version of the bedside head impulse test. It uses lightweight goggles to measure your eye response to rapid head turns with high accuracy, detecting subtle abnormalities the naked eye might miss. Vestibular evoked myogenic potentials (VEMPs) are another specialized test that measures how well specific parts of the balance organ respond to sound stimulation. These are more commonly used in specialized vestibular clinics than in general practice.
Blood Tests and Imaging
There is no standard blood test that diagnoses an inner ear infection. However, research has found that people with vestibular conditions tend to show elevated inflammatory markers, including C-reactive protein, higher white blood cell counts, and an increased ratio of certain immune cells. These findings can support a diagnosis of inflammation but aren’t specific enough to confirm it on their own. An inner ear protein called otolin-1 has shown promise as a more targeted marker, but it isn’t part of routine clinical practice yet.
MRI is not routinely ordered for a straightforward inner ear infection. It’s reserved for situations where the diagnosis is uncertain, where symptoms suggest something more serious, or where the doctor needs to rule out a tumor on the hearing and balance nerve. If your HINTS exam suggests a central (brain) cause, or if you have neurological symptoms like facial weakness, slurred speech, severe headache, double vision, or inability to walk, imaging becomes urgent.
Symptoms That Change the Diagnostic Urgency
The tricky reality of inner ear infections is that their symptoms overlap significantly with strokes affecting the balance centers in the brainstem or cerebellum. Johns Hopkins Medicine notes that it’s “impossible to exclude stroke without careful examination of the patient’s eye movements” when someone presents with new, severe, persistent vertigo alongside vomiting and difficulty walking. This is why the physical exam matters so much.
Vertigo that comes and goes in brief episodes, lasting under a minute and triggered only by head position changes, is almost certainly BPPV, not an infection. Vertigo that persists for hours or days, especially with hearing changes, points toward labyrinthitis or vestibular neuritis. And vertigo with any obvious neurological symptoms, like numbness on one side, difficulty speaking, or sudden severe imbalance, warrants emergency evaluation immediately.
Who Handles the Diagnosis
Most inner ear infections are initially diagnosed by an emergency physician or primary care doctor based on symptoms and a physical exam. Referral to an ENT (ear, nose, and throat specialist) is appropriate when infections keep recurring, when hearing loss accompanies the vertigo, or when symptoms don’t improve within the expected timeframe. Sudden, severe hearing loss in one ear is considered a medical emergency that warrants seeing an ENT as soon as possible, ideally within days, because treatment options for preserving hearing are time-sensitive.
An audiologist often works alongside the ENT, conducting the detailed hearing and vestibular function tests that confirm the diagnosis and measure the extent of damage. If your primary care doctor is confident in the diagnosis and your symptoms are resolving, you may not need specialist testing at all. But persistent balance problems, recurrent episodes, or hearing changes are strong reasons to push for a more thorough workup.