Vertigo happens when your brain receives conflicting signals about your body’s position and movement, almost always because something has gone wrong in the inner ear. The most common cause, by far, is tiny calcium crystals dislodging inside the ear and interfering with your balance organs. But infections, fluid buildup, migraines, head injuries, and certain medications can all trigger it too. Understanding which mechanism is behind your vertigo matters because the treatments are very different.
Loose Crystals in the Inner Ear (BPPV)
Benign paroxysmal positional vertigo, or BPPV, is the single most common cause of vertigo. Inside each ear, you have a small sensory organ called the utricle that contains tiny calcium crystals. These crystals normally stay put, helping you sense gravity and linear movement. But sometimes they break loose and drift into the semicircular canals, the curved tubes in your inner ear that detect head rotation.
The posterior canal is the most frequently affected because it sits at the lowest point relative to gravity, making it the natural landing spot for stray crystals. Once there, the crystals shift every time you move your head, pushing fluid through the canal and sending a false rotation signal to your brain. The result is a sudden, intense spinning sensation that lasts seconds to a minute, typically triggered by rolling over in bed, tilting your head back, or bending forward.
What causes the crystals to dislodge in the first place? Sometimes a head injury shakes them loose. Aging plays a role too, as the structures holding the crystals in place gradually degrade. In many cases, though, there’s no identifiable trigger. BPPV tends to come in episodes: you may have vertigo for days or weeks, then nothing for months before it returns.
Inner Ear Infections and Inflammation
Vestibular neuritis and labyrinthitis are two related conditions where inflammation damages the balance structures in the inner ear. Vestibular neuritis affects the nerve that carries balance signals to the brain. Labyrinthitis affects a broader area, the labyrinth, which houses both the balance and hearing organs. That’s why labyrinthitis often causes hearing loss or ringing in the ear alongside vertigo, while vestibular neuritis typically does not.
Both conditions often follow a viral respiratory infection. The herpes zoster virus (the same one responsible for shingles) has been linked to some cases, and in rare instances, Lyme disease or other bacterial infections are involved. Unlike BPPV, where vertigo comes in brief bursts tied to movement, these infections tend to cause constant, severe vertigo lasting days to weeks. Most people recover gradually as the inflammation subsides, though some experience lingering balance problems for months.
Fluid Pressure Buildup (Ménière’s Disease)
Ménière’s disease involves excess fluid pressure in the inner ear’s endolymphatic system, a network of fluid-filled chambers separated by thin, nerve-rich membranes. When pressure builds, it stresses these delicate membranes and disrupts both balance and hearing signals. The hallmark of Ménière’s is a cluster of four symptoms occurring together: episodes of spinning vertigo (sometimes violent), fluctuating hearing loss, low-pitched ringing or roaring in the ear, and a sensation of fullness or pressure in the affected ear.
Episodes can last anywhere from 20 minutes to several hours, then resolve on their own before recurring days, weeks, or months later. Over time, the repeated pressure fluctuations can cause progressive hearing loss. The exact reason some people develop this fluid imbalance isn’t fully understood, but it appears to involve problems with how the inner ear produces or absorbs its fluids.
Migraine-Related Vertigo
Vestibular migraine is one of the most underdiagnosed causes of vertigo. People with this condition experience episodes of vertigo lasting anywhere from five minutes to 72 hours, accompanied by migraine features like headache, sensitivity to light or sound, or visual auras. Not every episode includes a headache, which is part of why it’s often missed.
The underlying mechanism involves the nerve pathways that process both pain and balance information in the brainstem. These systems share extensive connections, and in people with vestibular migraine, the brain appears to have a dysfunction in how it integrates sensory and balance signals. Inflammation along nerve fibers that supply blood vessels in the inner ear may also play a role, essentially creating a feedback loop between the pain-processing and balance-processing systems. A genetic susceptibility likely contributes, given how commonly vestibular migraine runs in families.
Head Injuries
A blow to the head can cause vertigo through several mechanisms. The most straightforward is mechanical: the impact physically dislodges the calcium crystals in your inner ear, triggering BPPV. But more severe injuries, like concussions, can also damage the vestibular nerve or the brain regions that process balance information.
Post-traumatic vertigo can appear immediately after the injury or develop days to weeks later. In older adults, falls are the most common cause of traumatic brain injury, creating a concerning cycle where balance problems from aging lead to falls, and the resulting head trauma makes balance even worse.
Medications That Damage the Inner Ear
Certain medications can harm the sensory cells inside the inner ear that help you maintain balance. This is called ototoxicity, and the damage can sometimes be permanent. The classes most commonly responsible include a group of antibiotics used for serious bacterial infections (aminoglycosides), certain chemotherapy drugs (particularly platinum-based ones), and a type of diuretic used to remove excess fluid from the body (loop diuretics).
The risk depends on the dose, how long you take the medication, and whether you’re using more than one ototoxic drug at the same time. Kidney problems also increase risk because the drugs stay in your system longer. If you’re being treated with any of these medications, your care team will typically monitor your hearing and balance function throughout treatment.
Age-Related Vestibular Decline
Your balance system relies on three inputs working together: your inner ear, your vision, and sensors in your feet and legs that detect position and movement. Aging gradually degrades all three. The vestibular organs in the inner ear lose sensory cells over time, vision deteriorates, and the position sensors in the lower body become less reliable. This is why dizziness and balance disorders become increasingly common after age 60.
Medications that are more commonly prescribed in older adults, including sedatives and blood pressure drugs, can compound the problem by further impairing balance. The combination of vestibular degeneration, reduced muscle mass, and medication side effects explains why falls are such a significant concern in older populations.
How the Cause Is Identified
Because vertigo has so many possible origins, identifying the right cause starts with the pattern of symptoms. BPPV produces brief episodes triggered by specific head positions. Ménière’s disease involves longer episodes with hearing changes. Vestibular neuritis causes constant vertigo for days. Vestibular migraine produces episodes with migraine features.
For suspected BPPV, the standard diagnostic test is the Dix-Hallpike maneuver. You sit on an exam table while a provider turns your head 45 degrees to one side, then quickly guides you to lie back with your head hanging slightly off the edge. They watch your eyes for involuntary jerking movements called nystagmus. If your eyes start jumping while one ear is pointing toward the floor, the loose crystals are in that ear. No nystagmus means something other than BPPV is responsible.
For vertigo that doesn’t fit the BPPV pattern, providers use a combination of eye movement tests, hearing assessments, and sometimes imaging to distinguish between inner ear problems and less common causes originating in the brainstem or brain. The distinction matters: inner ear vertigo produces consistent, predictable eye movements, while brain-related causes produce eye movements that shift direction or appear alongside other neurological signs like double vision or difficulty speaking.