Vertigo is most often brought on by problems in the inner ear, where tiny structures responsible for balance send incorrect signals to the brain. The single most common cause is a condition called BPPV, where small calcium crystals break loose inside the ear and drift into the wrong place. But vertigo can also be triggered by infections, fluid buildup, migraines, dehydration, and in rare cases, problems in the brain itself.
Loose Crystals in the Inner Ear (BPPV)
Benign paroxysmal positional vertigo, or BPPV, accounts for roughly 17% to 42% of all vertigo cases and is by far the most common cause. Each of your inner ears contains three fluid-filled semicircular canals arranged at right angles to each other. Inside these canals, tiny hair cells detect the movement of fluid when you turn your head, and your brain uses those signals to figure out which way you’re moving. The problem starts when small calcium carbonate crystals, which normally sit in a different part of the ear, break free and drift into one of these canals. Once there, the crystals slosh around with the fluid and stimulate those hair cells at the wrong time, sending your brain a false signal that your head is spinning.
BPPV episodes are brief, usually lasting less than a minute, and are triggered by specific head movements: rolling over in bed, tilting your head back in the shower, or looking up at a high shelf. The crystals most often detach because of age-related wear and tear on the inner ear. Dizziness and balance problems affect about 30% of people over 60 and nearly 50% of those past 85, and BPPV is diagnosed in almost 40% of older adults who show up with vertigo. Head injuries, prolonged bed rest, and other inner ear conditions can also shake the crystals loose.
The good news is that BPPV responds well to a simple, non-drug treatment called the Epley maneuver, a series of guided head positions that move the crystals out of the canal and back to where they belong. About 72% of people feel immediate relief after one session, and that number climbs to around 92% within a week.
Inner Ear Infections
Two closely related infections can bring on sudden, severe vertigo that lasts days or even weeks. Vestibular neuritis is inflammation of the nerve that carries balance signals from your inner ear to your brain. Labyrinthitis involves the same nerve but also inflames the inner ear structures responsible for hearing, so it typically causes hearing changes alongside the vertigo. Both conditions usually follow a viral respiratory illness, though in rare cases they’ve been linked to herpes zoster (shingles) or Lyme disease.
Unlike BPPV, where episodes are short and positional, the vertigo from these infections tends to hit abruptly and stay constant for the first few days before gradually improving. Nausea and difficulty walking are common during the worst of it. Most people recover over several weeks as the brain learns to compensate for the damaged nerve signals, though some experience lingering unsteadiness for months.
Fluid Buildup in the Inner Ear (Ménière’s Disease)
Ménière’s disease causes unpredictable episodes of vertigo that can last anywhere from 20 minutes to several hours, paired with fluctuating hearing loss, a feeling of fullness or pressure in the ear, and ringing (tinnitus). The underlying problem is an abnormal increase in the volume of fluid inside the endolymphatic space, a sealed compartment in the inner ear. As that fluid swells, it distends the membranes that separate the balance and hearing structures, distorting the signals they send.
For a long time, researchers thought the fluid accumulated because the ear’s drainage system wasn’t absorbing it fast enough. That theory has been largely overturned. Current understanding points to disruptions in how ions are transported across membranes within the ear, with water following those ions by osmosis, similar to how a single cell regulates its own volume. Over time, the excess pressure damages the delicate hair cells in the inner ear, starting with those responsible for low-frequency hearing and eventually progressing to affect all frequencies. This may also explain why some people with Ménière’s report sensitivity to weather fronts or barometric pressure changes: the swollen membranes appear to make the ear abnormally responsive to very low-frequency pressure shifts.
Vestibular Migraine
Migraine doesn’t just cause headaches. In some people, it triggers vertigo episodes that can last anywhere from five minutes to three days. A vestibular migraine diagnosis requires at least five such episodes, along with a current or past history of migraine and at least one migraine feature during half or more of the vertigo attacks. Those features include one-sided pulsing head pain, sensitivity to light and sound, or visual aura.
What makes vestibular migraine tricky is that the vertigo and the headache don’t always show up together. You might have a spinning episode with no head pain at all, which can make it hard to connect the two. Common triggers overlap with those for regular migraines: menstruation, stress, poor sleep, dehydration, and certain foods. None of these triggers are specific enough to be used as diagnostic criteria on their own, but tracking them can help you identify patterns and reduce how often episodes occur.
Dehydration, Stress, and Other Lifestyle Triggers
You don’t always need an underlying ear condition for vertigo to strike. Dehydration reduces your blood volume and blood pressure, which means less blood reaches your brain. That alone can cause dizziness and a spinning sensation. Stress, fatigue, and caffeine can all heighten the sensitivity of your vestibular system, making you more prone to episodes, especially if you already have an underlying condition like BPPV or vestibular migraine. Even flying can set things off, thanks to the combination of cabin pressure changes, dehydration, and fatigue.
For people who experience recurrent vertigo, these lifestyle factors often act as amplifiers rather than root causes. Staying well-hydrated, managing stress, keeping a regular sleep schedule, and moderating caffeine intake won’t cure an inner ear disorder, but they can meaningfully reduce how often and how intensely episodes hit.
Growths on the Balance Nerve
An acoustic neuroma (vestibular schwannoma) is a slow-growing, noncancerous tumor on the nerve connecting the inner ear to the brain. While vertigo might seem like a natural symptom, it’s actually the main complaint in only about 3% of cases. The hallmark symptom is progressive hearing loss in one ear, which is the first thing noticed by 80% of patients. However, about 25% of people with the tumor report a more general sense of unsteadiness when specifically asked. Because the tumor grows slowly, the brain often compensates for the gradual balance disruption, which is why full-blown spinning vertigo is uncommon.
When Vertigo Signals Something in the Brain
Most vertigo originates in the inner ear, and while unpleasant, it isn’t dangerous. Central vertigo, caused by problems in the brainstem or cerebellum, is far less common but more serious. The key difference is in the accompanying symptoms. Inner ear vertigo tends to come with hearing changes or tinnitus, and the room spins in one consistent direction. Central vertigo, which can be caused by a stroke, multiple sclerosis, or a brain tumor, comes packaged with neurological symptoms: weakness or numbness on one side of the body, double vision, slurred speech, or difficulty swallowing.
A few specific eye signs also point to a brain-related cause. If the involuntary eye movements that accompany vertigo (nystagmus) change direction when you look in different directions, or if they move vertically rather than horizontally, the problem is more likely central. Another red flag is skew deviation, where one eye sits noticeably higher than the other. Any combination of vertigo with these neurological signs warrants urgent medical evaluation, as it can indicate a stroke affecting the back of the brain.
How the Cause Gets Identified
Diagnosing vertigo usually starts with a physical exam rather than imaging. For suspected BPPV, a clinician will guide you through the Dix-Hallpike maneuver: you sit upright, turn your head to one side, and lie back quickly while the clinician watches your eyes. If the crystals are displaced, your eyes will show a characteristic fluttering pattern after a short delay. The test has an estimated sensitivity of about 79% and a specificity of 75%, meaning it catches most cases but occasionally misses one or gives a false positive. When the result is unclear, a side-lying version of the test or repeat visits may be needed.
For conditions like Ménière’s disease or vestibular migraine, diagnosis relies more heavily on your symptom history: how long episodes last, what triggers them, and what other symptoms accompany the spinning. Hearing tests help confirm Ménière’s by detecting the low-frequency hearing loss that develops early. Imaging with MRI is typically reserved for cases where a tumor or brain-related cause is suspected, particularly when hearing loss is one-sided and progressive.