Updated 22 May 2015

Facial nerve palsy

Facial nerve palsy is possibly viral but the main cause is unknown.


Facial nerve palsy usually refers to a fairly sudden onset of weakness of one side of the face. The cause is unknown, possibly viral, and most cases clear up within three months. (In general, the wrong side of the face is felt to be abnormal: the abnormal side is the side which does not move). Although alarming, this is a benign condition.

It is also known as Bell's palsy or lower motor neuron facial weakness.

What is facial nerve palsy?

Damage to the facial nerve, usually in the region of the middle ear. It is not a stroke or multiple sclerosis.


Usually patients will have pain behind their ear for a day or two before facial palsy develops. Usual symptoms are that foodstuffs, particularly liquids, run out of the corner of the mouth. Since the muscles are weak, closure of the eye and of the lips are the most obvious symptoms. Difficulty closing the eye may cause drying and pain.


Diagnosis is made by history and examination. No special tests are usually required. Nerve conductions studies may be done, and the amplitude of the response may give an indication of prognosis, but this is rarely required.


Many treatments are pointless, although widely used. In particular, acupuncture, repeated nerve stimulation and physiotherapy are a waste of time and money.

If the diagnosis has been made within 48 hours, a brief course of prednisone may be given, the idea being that it may reduce swelling and inflammation of the nerve. Prednisone is an oral corticosteroid (like cortisone), is cheap, and in short courses has very few side effects.

Since the condition may be caused by a herpes virus (a hot topic of debate), there may be an indication for using the drug acyclovir (trade name Zovirax).

Great care may need to be taken looking after the eye, and various treatments may be needed, including artificial tears, particularly at nighttime, and sometimes the use of patches or tape to close the eye until the muscles regain their strength.


The overwhelming majority clear up in three months.

When do you call your doctor?

As soon as condition is noted, in order that prednisone may be started.


There is nothing to be done to prevent the condition.


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