Bell's palsy: Causes, symptoms and treatment
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This article gives you the key facts you need to know about Bell's palsy — including the causes, symptoms and treatment of Bell's palsy.
What is Bell's palsy?
Bell's palsy is a temporary weakness or paralysis of the seventh cranial nerve, which is also called the facial nerve.
The facial nerve extends from the base of the brain to the side of the face, where its fibers spread out and control the muscles of facial expression.
The facial nerve also controls movements of the eyelids and forehead and conveys taste sensations from the anterior two-thirds of the tongue.
Bells palsy typically occurs suddenly and without warning. Researchers have reported that Bell's palsy affects 23 people per 100,000 population per year, or about 1 in 60 to 70 people in a lifetime. It affects in women and men equally, and is most likely to occur between the ages of 10 and 40 years.
What causes Bell's palsy?
The cause of Bell's palsy is unknown, often is unknown, but the condition has been associated with certain viruses such as herpes simplex and herpes zoster (shingles).
Other risk factors that have been identified or suggested include diabetes and Lyme disease.
Bell's palsy symptoms
The primary symptoms of Bell's palsy are a droopy appearance of the face and mouth that affects just one half of the face.
Additional Bell's palsy symptoms may include:
Pain in or behind the ear
Numbness of the affected side of the face
Increased sensitivity to sounds (hyperacusis)
Altered taste on half of the front part of the tongue
Inability to fully close the eyelids of one eye (often causing dry eye)
The facial symptoms of Bell's palsy may look similar to those of a stroke. But in Bell's palsy, no other neurological signs or symptoms are present.
Bell's palsy symptoms typically are temporary, with most people experiencing a noticeable lessening of symptoms within three weeks. However full recovery can take up to six months, and up to 29 percent of people affected will have some degree of permanent Bell's palsy symptoms.
How does Bell's palsy affect the eyes?
Most people with Bell's palsy are unable to blink on the affected side of the face. Also, the lower eyelid of that eye may turn outward (a condition called ectropion).
Because the muscle that opens the eye is controlled by a different cranial nerve, you can easily open the affected eye but may not be able to close it fully.
As a result, most people with Bell's palsy suffer from an extreme form of dry eye syndrome known as exposure keratitis.
If you have been diagnosed with Bell's palsy or are experiencing symptoms of Bell's palsy, see an eye doctor near you to see if your eyes are being affected by the condition.
Bell's palsy treatment
Treatments that may be recommended for Bell's palsy include corticosteroid medications (such as prednisone) or antiviral drugs (such as acyclovir).
However, a meta-analysis of research studies found that these medications often do not resolve Bell's palsy symptoms or prevent permanent effects from the condition any better than a placebo treatment.
To prevent serious dry eye from Bell's palsy, frequent use of artificial tears and ocular lubricants are highly recommended, including the use of long-acting lubricating ointment at bedtime.
Failing to keep your eyes well-lubricated if you have Bell's palsy symptoms can result in significant eye discomfort, dry eyes and even a corneal ulcer that could cause permanent vision loss.
In some cases, the affected eyelid must be taped shut at bedtime to prevent the eye from remaining open and drying out while you sleep.
If you or a family member are experiencing symptoms of Bell's palsy, see an eye doctor near you immediately for dry eye evaluation and treatment.
Page updated June 2019