What is Bell’s palsy?
Bell’s palsy is a weakness (paralysis) that affects the muscles of the face. It is due to a problem with the facial nerve. The weakness usually affects one side of the face. Rarely, both sides are affected. Many people who have a Bell’s palsy at first think that they have had a stroke. This is not so. Bell’s palsy is very different to a stroke and full recovery occurs in most cases. Bell’s palsy is named after the doctor who first described it.
What is the facial nerve?
Facial nerve (also called the seventh cranial nerve) on each side of your face. Each facial nerve comes out from your brain, through a small tunnel in your skull just under your ear.
The nerve splits into many branches that supply the small muscles of the face that you use to smile, frown, etc. It also supplies the muscles that you use to close your eyelids.
Branches of the facial nerve also take taste sensations from your tongue to your brain.
Who gets Bell’s palsy?
Anyone can get Bell’s palsy, and it affects both men and women equally. It most commonly occurs between the ages of 10 and 40. Bell’s palsy is the most common cause of a sudden facial weakness. About 1 in 70 people has a Bell’s palsy at some stage in their life.
What causes Bell’s palsy?
It is thought that inflammation develops around the facial nerve as it passes through the skull from the brain. The inflammation may compress (squash) the nerve as it passes through the skull. The nerve then partly, or fully, stops working until the inflammation goes. If the nerve stops working, the muscles that the nerve supplies also stop working.
The cause of the inflammation is not known but, in most cases, it is probably due to a viral infection. There is some evidence that the cold sore virus (herpes simplex virus) or the chickenpox virus (varicella zoster virus) cause most cases of Bell’s palsy. Most people have chickenpox at some stage (usually as a child) and many people have cold sores. The virus does not completely go after you have chickenpox or a cold sore. Some virus particles remain dormant (inactive) in the nerve roots. They do no harm there, and cause no symptoms. For reasons that are not clear, the virus may begin to multiply again (re-activate). This is often many months or years later. In some cases, the ‘re-activated’ virus is thought to cause inflammation around the facial nerve to cause Bell’s palsy.
What are the symptoms of Bell’s palsy?
- Weakness of the facewhich is usually one-sided. The weakness normally develops quickly, over a few hours or so. You may first notice the weakness after getting up in the morning, and so it may appear quite dramatic. It may gradually become worse over several days. The effects of the weakness vary, depending on whether the nerve is partially or fully affected. These include the following:
- Your face may droop to one side. When you smile, only half of your face may move.
- Chewing food on the affected side may be a problem. Food may get trapped between your gum and cheek. Drinks and saliva may escape from the side of your mouth.
- You may not be able to close an eye. This may cause a watery or dry eye.
- You may not be able to wrinkle your forehead, whistle or blow out your cheek.
- You may have some difficulty with speech, as the muscles in the side of the face help in forming some words. For example, words beginning with a P.
- Most cases are painless or cause just a mild ache. However, some people develop some pain near the ear which can last for a few days.
- Loud sounds may be uncomfortable and normal noises may sound louder than usual. This is because a tiny muscle in the ear may stop working.
- loss of sense of taste on the side of the tongue that is affected.