Bell's palsy: Symptoms, diagnosis and treatment
What is Bell's palsy?
Bell's palsy causes temporary weakness or paralysis to muscles, usually on one side of the face.
In most cases, a person with Bell's palsy will experience partial palsy or mild muscle weakness.
An eyelid and the mouth may also be affected.
Bell's palsy is rare, affecting around 1 in 5,000 people each year in the UK.
In very rare cases, there can be no movement at all or complete palsy.
In around 7 in 10 cases, people make a complete recovery from Bell's palsy.
The symptoms of Bell's palsy are similar to some of those for a stroke, which is a medical emergency.
Bell's palsy is thought to be due to inflammation of the seventh cranial nerve, also known as the facial nerve. Although the cause is not fully known, a viral infection such as herpes may be to blame.
Although Bell's palsy can affect anyone, it is more common in pregnancy and in people with diabetes and those with HIV.
Bell's palsy rarely recurs in the same person.
What are the symptoms of Bell's palsy?
Bell's palsy tends to come on very suddenly. You may go to bed one night with no noticeable symptoms, only to look in the mirror the next morning and notice that your face appears to be drooping. Some people notice pain behind their ear a day or two before they notice any weakness. Others comment that sounds seem abnormally and uncomfortably loud several days before the development of paralysis. Within a day or two, the paralysis usually reaches its peak. Most people start to recover within a couple of weeks and are completely recovered within three months.
The symptoms of Bell's palsy can include:
- Drooping of the muscles on one side of the face
- Inability to close the eyelid on the affected side and the inability to blink
- Excess or decreased tearing
- Difficulty chewing on the affected side
- Decreased sense of taste on the affected side
- Twitching of the muscles on the affected side
- Pain or numbness behind the ear on the affected side of the face
- Hyperacusis, an increase in sensitivity to noise on the affected side of the face
Seek urgent medical advice about Bell's palsy if you have:
- Weakness or drooping of your facial muscles
- You cannot blink or close your eye
- You have numbness, pain or twitching of your facial muscles
How is Bell's palsy diagnosed?
There is no test that can absolutely show that you have Bell's palsy. Doctors refer to the diagnosis of Bell's palsy as a "diagnosis of exclusion” which means that Bell's palsy is usually diagnosed after other conditions have been ruled out. Your doctor will do a complete and careful physical examination. He or she is likely to notice that when you unsuccessfully try to close your eyelid, your eye on the affected side will drift up and outwards; this is called the Bell phenomenon. In order to rule out other conditions, your doctor will probably test your hearing and your sense of balance. He or she may arrange other tests such as skull X-rays, a computed tomography (CT) scan or magnetic resonance imaging (MRI). These tests may help clarify the diagnosis and may help predict the speed and extent of your recovery.