Bell Palsy is a condition associated with the acute onset of facial paralysis due to palsy of the seventh lower motor neuron (cranial nerve seven).
The presence of mastoid pain might be a diagnostic clue, as this symptom often precedes the onset of actual facial paresis.
Other associated findings include: typically unilateral facial muscle paralysis affecting both the upper and lower parts of the face; tear overflow and dry eyes; altered taste; hyperacusis or sound sensitivity; sensation spared; no other cranial nerves involved.
It is often associated with viruses such as HIV, Epstein-Barr, and Hepatitis B, but most commonly herpes simplex.
If facial paralysis is bilateral, consider Lyme disease as a possible etiology.