Two questions must be asked by the clinician when assessing a patient who presents with an acute facial weakness:

  1. Is this an upper or lower motor neurone lesion?
  2. Are there any additional features that exclude Bell’s Palsy (idiopathic lower motor neuron facial nerve palsy)?

The most common presenting complaint in acute facial palsy is of unilateral facial weakness, which may have been noticed by the patient themselves or by a family member.

Although facial numbness is a commonly described in acute peripheral facial palsy, formal testing of the trigeminal nerve should demonstrate normal sensation. Subjective reduced sensation is caused by reduced facial muscle tone.

Depending on the cause of the facial nerve palsy, other features of the history may be elicited.
Approximately 50% of patients with Bell’s palsy experience facial pain, aural fullness or postauricular pain and in 25% of cases this precedes the paresis by 2-3 days [4].

Other symptoms, such as recent trauma, fever, headache, earache, rash, weight loss or other neurological or systemic upset may suggest an alternative cause other than Bell’s palsy.

The image shows a patient with a right sided lower motor neuron facial nerve palsy.