Vertigo most often starts because something went wrong in your inner ear, not your brain. The single most common cause is tiny calcium crystals that break loose inside the ear and drift into the wrong chamber, sending false motion signals to your brain. But several other conditions, from viral infections to migraines, can trigger the same spinning sensation. Understanding which mechanism is behind your vertigo is the first step toward fixing it.
How Your Balance System Works
Your brain figures out where you are in space by combining three streams of information: signals from fluid-filled organs in your inner ear, what your eyes see, and feedback from the muscles and joints throughout your body. Inside each inner ear, a network of tiny chambers called the vestibular labyrinth is filled with fluid and lined with microscopic hair cells. When your head moves, the fluid shifts, bending those hair cells, which fire signals along the vestibular nerve to your brain.
Your brain constantly cross-checks these ear signals against what your eyes and body are reporting. When all three inputs agree, you feel stable. Vertigo happens when they conflict, usually because one inner ear is sending inaccurate signals. Your brain interprets the mismatch as movement, and you feel like the room is spinning even though you’re standing still.
Loose Crystals in Your Ear (BPPV)
Benign paroxysmal positional vertigo, or BPPV, is the most common cause of vertigo, with an estimated lifetime prevalence of about 2.4 percent of the population. If your vertigo hits in short bursts when you tilt your head, roll over in bed, or look up, BPPV is the most likely explanation.
Here’s what happens: small calcium carbonate crystals called otoconia normally sit in a part of the inner ear called the utricle, where they help you sense head tilt and acceleration. Sometimes these crystals break free and fall into one of the semicircular canals, the curved tubes designed to detect rotational movement. Once inside a canal, the loose crystals slosh around and mimic fluid movement, tricking your brain into thinking your head is spinning rapidly. The result is a burst of dizziness, nausea, and involuntary eye movements that typically lasts less than a minute.
Why do the crystals come loose in the first place? Head injuries, prolonged bed rest, aging, and sometimes no identifiable reason at all. BPPV is more common after age 50 and affects women roughly twice as often as men. The good news is that it’s very treatable. A provider can confirm it with a simple test where you lie back quickly with your head turned to one side. If your eyes show a characteristic twitching pattern while one ear points toward the floor, the crystals are in that ear. From there, a series of guided head movements can reposition the crystals back where they belong, often resolving symptoms in one or two sessions.
Viral Infections That Inflame the Inner Ear
If your vertigo came on suddenly, felt severe, and lasted for hours or days rather than seconds, a viral infection affecting your inner ear or its nerve is a strong possibility. Two closely related conditions fall into this category.
Vestibular neuritis is inflammation of the vestibular nerve, the cable connecting your inner ear’s balance organs to your brain. It typically follows a viral illness like a cold or flu, though sometimes the triggering infection goes unnoticed. The hallmark is intense, continuous vertigo lasting days, often with nausea and difficulty walking, but no hearing loss.
Labyrinthitis involves inflammation of the inner ear itself, including the structures responsible for both balance and hearing. Because the hearing apparatus is also affected, labyrinthitis can cause hearing loss or ringing in the ear alongside vertigo. Bacterial infections of the middle ear occasionally spread inward and cause labyrinthitis, though viral infections are by far the more common trigger.
Both conditions typically improve on their own over days to weeks as the inflammation resolves. The brain gradually learns to compensate for any lasting damage to the nerve or inner ear, a process called vestibular compensation that can take several weeks.
Ménière’s Disease and Fluid Buildup
Ménière’s disease causes recurring episodes of vertigo that last 20 minutes to several hours, often accompanied by a feeling of fullness or pressure in one ear, fluctuating hearing loss, and ringing or roaring sounds. The underlying problem is a buildup of fluid (endolymph) inside the inner ear. When too much fluid accumulates, it disrupts the balance and hearing signals traveling to your brain.
No one knows exactly why the fluid builds up. What is known is that certain lifestyle factors can provoke or worsen episodes. A high-sodium diet increases fluid retention in the inner ear. Caffeine, alcohol, and nicotine have all been identified as potential triggers, though sensitivity varies from person to person. Many people with Ménière’s find that reducing salt intake and avoiding these substances decreases the frequency and severity of attacks.
Vestibular Migraine
Migraines don’t always mean a pounding headache. Vestibular migraine causes episodes of vertigo that can last minutes to days, and a throbbing headache may or may not accompany the spinning. Nausea, sensitivity to motion, and even temporary hearing changes can occur. Different episodes in the same person can look quite different, with varying combinations of symptoms each time.
This diagnosis is tricky because migraine attacks can also be triggered by vestibular stimulation, meaning an inner ear problem and a migraine problem can overlap or mimic each other. Vestibular migraine is typically diagnosed after other ear disorders have been ruled out and the episodes fit a pattern consistent with migraine history.
Medications That Damage the Inner Ear
Certain medications are toxic to the inner ear’s delicate hair cells, a side effect known as ototoxicity. If your vertigo started during or after a course of medication, this is worth investigating. The most commonly implicated drug classes include:
- Certain antibiotics used for serious bacterial infections, particularly the aminoglycoside family (gentamicin, tobramycin, and others given by IV in hospital settings)
- Chemotherapy drugs, especially platinum-based agents used to treat various cancers
- Loop diuretics (water pills) prescribed for heart failure or high blood pressure
- High-dose aspirin, which can cause reversible dizziness and ringing
Environmental exposures to mercury, lead, and carbon monoxide can also damage vestibular function. Ototoxic damage is sometimes reversible when the offending substance is stopped early, but in other cases it becomes permanent.
When Vertigo Signals Something More Serious
The vast majority of vertigo originates in the inner ear and, while miserable, isn’t dangerous. Rarely, vertigo can signal a problem in the brain itself, particularly a stroke affecting the brainstem or cerebellum. This distinction matters because the treatment and urgency are completely different.
Inner ear vertigo (peripheral) tends to be intense but comes with consistent, predictable eye movements and worsens with head position changes. Brain-related vertigo (central) often presents with subtler spinning but is accompanied by red flags: difficulty walking or coordinating movements, double vision, slurred speech, numbness on one side of the body, or nystagmus (involuntary eye movements) that changes direction when you look in different directions. Vertical misalignment of the eyes, where one eye sits higher than the other, is another sign pointing toward a brainstem problem.
If your vertigo came on suddenly alongside any of these neurological symptoms, that combination requires emergency evaluation. Emergency physicians use a specific set of eye and head movement tests to differentiate the two, and imaging may follow if a central cause is suspected.
Other Contributing Factors
Beyond the major causes, several everyday factors can trigger or worsen vertigo. Head trauma, even mild concussions, can dislodge inner ear crystals or cause vestibular nerve damage. Prolonged bed rest after surgery or illness increases the risk of BPPV. Stress and sleep deprivation don’t cause vertigo directly but can lower the threshold for episodes in people with vestibular migraine or Ménière’s disease.
Age is one of the strongest risk factors across all types of vertigo. The crystals in your inner ear become more brittle over time, blood flow to the vestibular organs decreases, and the brain’s ability to compensate for sensory mismatches slows. This is why vertigo becomes increasingly common after middle age, though it can strike at any point in life.