The short answer: one label depends on position, while the other names a nerve problem.
The National Institute on Deafness and Other Communication Disorders describes BPPV as a brief, intense spell of vertigo that a specific change in head position triggers. Rolling over in bed, looking up, or bending down are common examples.
The same source describes vestibular neuritis, also called vestibular neuronitis, as inflammation of the vestibular nerve that primarily causes vertigo. A symptom list cannot confirm either diagnosis. The pattern gives a clinician a place to start.
BPPV has a clear link to a change in head position.
BPPV happens when loose calcium particles from the inner ear enter a semicircular canal and disturb its motion signal. That is why the same head movement may trigger a short spinning spell again and again.
The American Academy of Otolaryngology and Head and Neck Surgery guideline tells clinicians to use positional testing and watch for a matching eye movement. A history that sounds like BPPV still needs that check.
Vestibular neuritis refers to inflammation of the balance nerve.
The vestibular nerve carries balance signals from the inner ear toward the brain. Vestibular neuritis names inflammation of that nerve. It does not get its name from one head position or one home test.
Sudden vertigo can have more than one cause. A clinician may need to consider the timing, triggers, hearing symptoms, eye findings, headache, medicine use, and neurological signs before using a label.
The examination helps separate similar descriptions.
For suspected BPPV, the professional guideline uses the Dix-Hallpike test for the common posterior-canal pattern and a supine roll test when another canal may be involved. The eye movement and the vertigo response both matter.
NIDCD notes that balance evaluation may also include a hearing exam, eye-movement testing, blood tests, or imaging when the history and examination call for them. No single list of tests fits every person.
Some sudden dizziness patterns need emergency care.
The Centers for Disease Control and Prevention lists sudden dizziness, trouble walking, loss of balance, and loss of coordination among possible stroke signs. One-sided weakness or numbness, trouble speaking, sudden vision trouble, or a sudden severe headache are other warning signs.
Call 911 when those signs may be present. Do not wait for a routine office reply and do not use a web article to rule out stroke.
Write down the pattern before an evaluation.
Note whether a head movement starts the spinning, how long a spell lasts, whether it also happens at rest, and whether you have hearing change, ringing, headache, vision change, weakness, numbness, falls, or fainting.
Bring a full medicine and supplement list. These details do not diagnose the cause, but they give the clinician a clearer record to assess.