Why do allergies cause dizziness?

Yes they can: Allergies can interfere with normal nasal and ear function which then causes a problem with a structure known as semicircular canals. These are part of the ear and help tell your brain where your head is located.

Allergies: Allergies can cause dizziness if your nose is congested. You need a nasal spray or see an allergist for adequate control of your allergies.