Sudden dizziness can be caused by a variety of factors, including inner ear disturbance, motion sickness, medication effects, poor circulation, infection, injury, and neurological disorders. Some other possible causes of sudden dizziness include anxiety, stress, dehydration, hypoglycemia, and medication side effects.

Symptoms of sudden dizziness may include feeling lightheaded, off-balance, giddy, or faint. The episode may last seconds or days and may recur. If you experience any recurrent, sudden, severe, or prolonged and unexplained dizziness or vertigo, it is recommended to see a doctor. Get emergency medical care if you experience new, severe dizziness or vertigo along with any of the following: hearing loss, changes in vision or speech, numbness, or weakness in the face or one or more limbs.

Some inner ear conditions that can cause sudden dizziness include benign paroxysmal positional vertigo (BPPV), Menieres disease, and acoustic neuroma. If you experience sudden dizziness, lying still in a darkened room may help, but some causes need medical treatment.