Bell’s palsy is an acute condition that causes weakness or paralysis to the muscles of one side of the face. The weakness or paralysis can also affect the eyelid, meaning that someone with the condition cannot close their eye. The cause of Bell’s palsy is unknown, although many researchers believe that the herpes virus is responsible.
Bell’s palsy is a relatively rare condition. Published figures vary, but in England and Wales it is estimated that every year, 25-35 out of every 100,000 people develop Bell’s palsy. The condition usually develops between 15-40 years of age, and men and women are equally affected.
Bell’s palsy is more common in pregnant women and those with diabetes. The reasons for this are unclear.
The prognosis for Bell’s palsy is usually favourable, with 85% of people making a full recovery within nine months, and most people with the condition noticing a marked improvement in their symptoms within three weeks.
Steroid medications are sometimes used to speed up the recovery process. It is important to take good care of the affected eye during the recovery process.
The majority of the muscles in your face are controlled by a single nerve, known as the facial nerve.
The facial nerve passes through a narrow gap of bone on its way from your brain to your face. Bell’s palsy is thought to occur because a virus, usually the herpes virus, causes the nerve to become inflamed. If the nerve is inflamed, it will press against the cheekbone.
If the facial nerve is compressed, it is likely to become damaged, interfering with the signals that your brain is sending to the muscles in your face. The interference results in the weakness, or paralysis, that is characteristic of cases of Bell’s palsy.
You should see your GP within 72 hours of developing symptoms of Bell's palsy because studies have shown that treatment is most effective if it is started within this time period.
Bell's palsy is diagnosed using a process that is known as diagnosis by exclusion. Your GP will look for any evidence that your symptoms may be caused by another health condition, such as Lyme disease (a bacterial infection caused by ticks), or tumor.
Diagnosis by exclusion involves carrying out a detailed physical examination of your head, ears and neck. Your GP will also check the muscles in your face in order to confirm whether only the facial nerve is affected.
If your GP cannot find any evidence to suggest other symptoms, such as the characteristic rash that is left by ticks, in Lyme disease, or a change in your facial structure that could suggest a tumor, a diagnosis of Bell's palsy can usually be made.
If your GP is unsure whether Bell's palsy is the cause, they may refer you to an ear, nose and throat (ENT) specialist for further testing. Possible further tests are described below.
Electromyography (EMG) is where electrodes are placed on your face, and a machine is used to measure the electrical activity in your nerves. An EMG can provide more information about the location and extent of any nerve damage.
Imaging scans, such as a magnetic resonance imaging (MRI) scan, that uses radio waves and a strong magnetic field to produce a detailed image of the inside of your body, or a computerised tomography (CT) scan, may be able to detect other causes of your symptoms, such as an infection, or tumour.
Symptoms of Bell’s palsy include:
In most cases of Bell’s palsy, the symptoms will begin to improve within three weeks.
In the past, there has been some disagreement among health professionals about whether Bell's palsy is best treated using steroids, anti-viral medications, or a combination of both.
However, following a large-scale medical trial that was completed in 2007, the evidence seems to suggest that steroids are the most effective treatment method and, specifically, a steroid medication called prednisolone.
Prednisolone works by helping to reduce inflammation, which should then help to speed up your recovery.
Most people with Bell's palsy are advised to take prednisolone tablets twice-a-day, for 10 days.
Possible side effects of prednisolone include:
However, these side effects should improve within a few days as your body gets used to the medication. Do not drive if you find that your medication is making you dizzy, or sleepy.
See your GP if you develop symptoms of oral thrush because the condition can usually be successfully treated using an anti-fungal medication. The main symptom of oral thrush is white, cream, or yellow spots that appear on the inside of your mouth and tongue.
As you come to the end of your course of steroid medication, your GP may recommend that you gradually reduce your dose. This will help to reduce the possibility of you experiencing any withdrawal symptoms, such as tiredness, or vomiting.
Tears play an important part in helping to protect your eyes by keeping them clean and free of dust, and preventing bacteria from causing eye infections.
However, if your eye is constantly exposed, your tears can evaporate, leaving your eye vulnerable to damage and infection. It is therefore very important to keep your eye lubricated.
Your GP will give you eye drops that contain 'artificial tears' that you will need to use during the day, plus an ointment which you should use at night. If you are unable to shut your eye during the night time, your GP will give you some surgical tape that you can use to tape your eye shut.
If your eye symptoms worsen, you should go straight to your local accident and emergency (A&E) department, or the ophthalmologist.
The majority of people who have Bell's palsy will make a full recovery within nine months. If you have not made a complete recovery by this time, you may have experienced more extensive nerve damage, and further treatment may be required.
One treatment option is known as 'mime therapy'. Mime therapy is a form of physiotherapy where the physiotherapist will teach you a series of exercises that will strengthen the muscles in your face, improving their coordination and range of movement.
Physiotherapy has been successful in a number of Bell's palsy cases, although it may not be suitable, or effective, for everyone.
Another possible treatment option is plastic surgery. While the surgeon may not be able to restore nerve function, they may be able to improve the appearance and symmetry of your face.