Infectious

Sudden onset facial palsy is a medical emergency and requires urgent assessment by a physician to rule out potentially life threatening conditions.

A number of rare infections, such as mycobacterium infections (tuberculosis, Cat Scratch Fever, mycobacterium avium intracellulare MAI) and polio virus infections can affect the facial nerve. These conditions are extremely rare, and require special biopsies and stains for diagnosis. In general, the weakness that arises from polio is irreversible.