Vertigo happens when your brain receives false signals about movement, almost always because something has gone wrong in the inner ear. Less commonly, it originates from a problem in the brain itself. Nearly 40% of adults over 55 develop some form of dizziness or vertigo over a ten-year period, making it one of the most common reasons people visit a doctor. The causes range from harmless (tiny crystals shifting out of place) to serious (stroke), so understanding how vertigo develops helps you recognize what you’re dealing with.
How Your Balance System Works
Your inner ear contains a network of fluid-filled structures called the vestibular system. Inside these structures are tiny hair cells that act as motion sensors. When you move your head, the fluid shifts, bending those hair cells, and they fire nerve signals to your brain reporting exactly how your head is oriented and how fast it’s rotating.
Two types of structures handle different kinds of movement. Three semicircular canals detect rotation, like turning your head side to side or tilting it. Two otolith organs detect linear movement and gravity, like going up in an elevator or leaning forward. The otolith organs contain small calcium crystals that sit on top of the hair cells, adding weight so they respond to gravity. When any part of this system sends signals that don’t match what your eyes and body are telling your brain, you experience vertigo.
Loose Crystals: The Most Common Cause
The single most common cause of vertigo is BPPV (benign paroxysmal positional vertigo). Those tiny calcium crystals in the otolith organs can break free and drift into the semicircular canals, where they don’t belong. Once there, they slosh around in the fluid every time you change head position, pushing on hair cells and sending false rotation signals to your brain.
The result is brief, intense spinning that hits when you roll over in bed, look up, or tilt your head back. Episodes typically last less than a minute but can be severe enough to cause nausea. BPPV can happen after a head injury, but often there’s no clear trigger. It’s more common as you age, likely because the crystals naturally loosen over time. A doctor can confirm the diagnosis with a simple positional test: they turn your head 45 degrees to one side and quickly guide you backward so your head hangs slightly off the exam table. If your eyes start jumping involuntarily in a specific pattern, dislodged crystals are the cause.
Fluid Pressure Buildup in the Inner Ear
Ménière’s disease causes vertigo through a completely different mechanism. The inner ear continuously produces and drains a potassium-rich fluid called endolymph. When drainage is blocked or production is excessive, fluid pressure builds up and distorts the delicate membranes separating the inner ear’s compartments. Eventually, those membranes can rupture, allowing fluids with very different chemical compositions to mix. This mixture disrupts the nerve receptors, temporarily shutting down the balance nerve on that side and creating a sudden, violent sense of spinning.
Ménière’s episodes are far longer than BPPV, often lasting 20 minutes to several hours. They come with a characteristic set of four symptoms: vertigo, fluctuating hearing loss, a low-pitched ringing or roaring in the ear, and a feeling of fullness or pressure in the affected ear. The condition tends to be episodic, with attacks that come and go unpredictably over months or years.
Viral Infections That Inflame the Inner Ear
Two related conditions, vestibular neuritis and labyrinthitis, cause vertigo when inflammation damages the inner ear or the nerve connecting it to the brain. Both often follow a viral respiratory infection and can occasionally be triggered by herpes viruses or, rarely, Lyme disease.
Vestibular neuritis affects only the balance nerve, so the main symptom is prolonged, severe vertigo without significant hearing loss. Labyrinthitis inflames the entire inner ear chamber, causing both vertigo and hearing loss. Unlike the brief spells of BPPV, the vertigo from these conditions can last days to weeks at full intensity before gradually improving as the brain learns to compensate for the damaged side.
Migraine-Related Vertigo
People with a history of migraines can develop vertigo as a direct symptom of their migraine attacks. Vestibular migraine produces episodes of moderate to severe spinning or dizziness lasting anywhere from five minutes to 72 hours. The vertigo may occur with or without a headache, which is why it’s often missed or misdiagnosed.
Having migraines roughly doubles the risk of developing vertigo over time. The connection works both ways: vestibular stimulation (like spinning or being on a boat) can actually trigger migraine attacks in susceptible people. At least five episodes of vestibular symptoms combined with a personal history of migraine are needed before this diagnosis is considered.
Head Injuries and Concussions
A blow to the head can cause vertigo through several pathways at once. The direct impact sends a pressure wave through the fluid-filled inner ear, damaging the delicate sensory cells. This is sometimes called labyrinthine concussion. The same impact can also shake loose the calcium crystals that cause BPPV, or in more severe cases, fracture the temporal bone surrounding the inner ear.
Concussions also damage the brain’s ability to process balance signals. Rotational forces during impact shear nerve fibers throughout the brain, disrupting the networks that integrate information from the inner ear, eyes, and body. This is why post-concussion dizziness can persist for weeks or months even after the inner ear itself has healed. Some people also develop strain-induced vertigo, where coughing, lifting, or loud sounds provoke spinning, which can indicate a tear in the membrane separating the inner ear from the middle ear.
Medications That Trigger Vertigo
A surprisingly wide range of medications list vertigo as a side effect. Some of the most common categories include certain antibiotics (particularly aminoglycosides), seizure medications, blood pressure drugs, anti-inflammatory medications, and even common acid reflux drugs like omeprazole. Codeine and other opioid painkillers can also cause it.
Some of these drugs are directly toxic to the inner ear’s sensory cells. Aminoglycoside antibiotics and certain diuretics fall into this category, and the damage can sometimes be permanent if the medication isn’t stopped in time. Others cause vertigo through their effects on the brain or blood pressure without harming the ear itself. If vertigo starts or worsens after beginning a new medication, that connection is worth investigating.
When Vertigo Comes From the Brain
Most vertigo originates in the inner ear (peripheral vertigo), but a small percentage comes from problems in the brain itself (central vertigo), most concerning among them being stroke. A stroke affecting the back of the brain can present as sudden vertigo with no other obvious neurological symptoms in up to 20% of cases, which makes it easy to mistake for a simple inner ear problem.
There are physical signs that help distinguish the two. With inner ear vertigo, the eyes drift involuntarily in one consistent direction, and when the head is turned quickly, the eyes lag behind and then snap back to catch up. With brain-related vertigo, the eyes may change direction depending on where the person looks, and the head-turning test looks normal. Vertical misalignment of the eyes, where one eye sits higher than the other, also points toward a brain cause. The presence of any other neurological symptoms like slurred speech, weakness on one side, or difficulty walking makes a brain cause much more likely.
Risk Factors That Increase Your Chances
Age is the strongest predictor. The older you are, the more likely the calcium crystals in your inner ear have loosened, the more cumulative damage your vestibular system has absorbed, and the less efficiently your brain compensates for balance disruptions. Having migraines is the other major risk factor, raising the likelihood of developing vertigo by about 63% independent of age. Beyond those two, prior head trauma, ear infections, prolonged bed rest, and a family history of Ménière’s disease all elevate risk. Women experience vertigo more frequently than men across nearly every cause, though the reasons for this disparity aren’t fully understood.