Vertigo happens when your brain receives conflicting signals about balance and movement, most often because something has gone wrong in your inner ear. The single most common cause is tiny calcium crystals dislodging inside your ear canal, but vertigo can also result from viral infections, migraines, head injuries, reduced blood flow to the brain, and certain medications. Understanding the specific trigger matters because the treatment, timeline, and outlook differ significantly depending on the cause.
Loose Crystals in the Inner Ear (BPPV)
Benign paroxysmal positional vertigo, or BPPV, is the most frequent cause of vertigo. Your inner ear contains tiny calcium carbonate crystals that help detect gravity and linear motion. When these crystals break loose and drift into one of the semicircular canals (the fluid-filled tubes that sense head rotation), they slosh around and send false motion signals to your brain. The result is brief but intense spinning, usually triggered by specific head movements like rolling over in bed, tilting your head back, or bending forward.
Episodes typically last under a minute but can be disorienting enough to cause nausea. BPPV can develop after a head injury (roughly 28% of people with head trauma develop it), but it also occurs spontaneously, especially in older adults. The crystals can dislodge for no obvious reason, which is why many people feel blindsided by their first episode.
To confirm BPPV, a doctor performs a simple bedside test: they turn your head 45 degrees to one side, then quickly guide you from sitting to lying down with your head slightly hanging off the table. If the loose crystals shift, your eyes will make involuntary twitching movements called nystagmus. That eye movement confirms the diagnosis. If nystagmus doesn’t appear, something else is causing your vertigo.
Viral Infections That Inflame the Inner Ear
Two closely related conditions, vestibular neuritis and labyrinthitis, occur when a viral infection inflames the nerve that carries balance signals from your inner ear to your brain. Common culprits include herpes viruses (the same family responsible for cold sores, chickenpox, and shingles), influenza, measles, mumps, and Epstein-Barr virus (mono). Cold or flu symptoms typically appear one to two weeks before the vertigo hits.
Unlike BPPV, which comes in short bursts, vestibular neuritis can cause continuous, severe vertigo lasting days. Labyrinthitis is essentially the same condition but also affects hearing, so you may notice muffled sound or ringing in one ear alongside the spinning. Bacterial infections can cause these conditions too, though that’s rare. Most people recover over several weeks as the inflammation subsides, though some experience lingering imbalance for months.
Vestibular Migraine
Migraine is the most common cause of vertigo that originates in the brain rather than the ear. Vestibular migraine produces episodes of moderate to severe spinning or dizziness lasting anywhere from five minutes to 72 hours. At least half of episodes come paired with classic migraine features: a one-sided, pulsating headache that worsens with physical activity, sensitivity to light and sound, or visual aura.
What makes vestibular migraine tricky is that you don’t always get a headache with every episode. Some people experience only the vertigo, which can lead to years of misdiagnosis. A formal diagnosis requires at least five episodes with the features described above, plus a current or past history of migraines. If you’ve had migraines before and now experience unexplained bouts of vertigo, the two are likely connected.
Fluid Buildup in the Inner Ear (Ménière’s Disease)
Ménière’s disease develops when excess fluid called endolymph accumulates in the inner ear, disrupting the balance and hearing signals sent to your brain. The hallmark pattern is episodes of vertigo lasting 20 minutes to several hours, accompanied by fluctuating hearing loss in one ear, a feeling of fullness or pressure in that ear, and ringing or roaring sounds (tinnitus).
No one knows exactly why this fluid builds up. The condition tends to affect one ear at a time, and episodes can be unpredictable, sometimes clustering together over weeks and then disappearing for months. An ENT specialist diagnoses Ménière’s through a combination of hearing tests, a neurological exam, and ruling out other conditions that mimic its symptoms. Over time, repeated episodes can cause permanent hearing loss in the affected ear.
Head Injuries and Concussions
A blow to the head can trigger vertigo through several mechanisms. The most common is simply knocking those inner ear crystals loose, causing post-traumatic BPPV. About 28% of people who sustain head trauma develop this type of vertigo. It usually shows up within days and responds to the same repositioning treatments used for regular BPPV.
More concerning is when head trauma tears the thin membrane separating the inner ear from the middle ear, creating a fluid leak. This typically causes symptoms within 24 to 72 hours of injury. In rarer cases, trauma can trigger a condition resembling Ménière’s disease, though this may take months or even years to develop after the initial injury.
Reduced Blood Flow to the Brain
Vertebrobasilar insufficiency occurs when blood flow to the back of the brain, the region controlling balance and coordination, drops because of narrowed or blocked arteries. Plaque buildup from cholesterol and calcium (atherosclerosis) is the most common culprit. Vertigo from this cause tends to feel different: it may come with difficulty walking, slurred speech, double vision, or weakness on one side of the body.
Risk factors include being over 50, having high blood pressure, high cholesterol, diabetes, a history of smoking, obesity, or atrial fibrillation. Men face roughly twice the risk compared to women. Black Americans also have a higher risk than other ethnic groups. If you’re experiencing vertigo alongside any neurological symptoms like vision changes, trouble speaking, or sudden coordination problems, this is a medical emergency because the same mechanism that causes vertebrobasilar insufficiency can also cause stroke.
How to Tell Ear-Related From Brain-Related Vertigo
The distinction between peripheral vertigo (originating in the ear) and central vertigo (originating in the brain) is the most important thing emergency doctors assess. Peripheral causes like BPPV, vestibular neuritis, and Ménière’s disease are far more common and generally not dangerous. Central causes, including stroke and vertebrobasilar insufficiency, are rarer but require immediate treatment.
A few patterns help separate the two. Ear-related vertigo is usually triggered or worsened by head position changes, comes with hearing symptoms, and produces eye twitching that stays consistent in one direction. Brain-related vertigo often causes eye movements that change direction when you look different ways, vertical misalignment of the eyes (one eye sits higher than the other), and may be accompanied by neurological symptoms like numbness, weakness, or difficulty with speech or swallowing. Doctors use a specific three-part eye examination to distinguish between the two in emergency settings.
Medications That Can Cause Vertigo
More than 200 medications are considered potentially damaging to the inner ear. The classes most likely to cause vertigo or balance problems include certain antibiotics (particularly a group used for serious infections), some chemotherapy drugs, loop diuretics (water pills), and high doses of aspirin. The damage can be temporary or, in some cases, permanent depending on the drug and duration of use.
If you notice new dizziness or spinning after starting a medication, that timing is worth mentioning to whoever prescribed it. Dose adjustments or switching to an alternative can often resolve drug-related vertigo before lasting damage occurs.