Bell's Palsy

Bell's palsy is a temporary weakness or paralysis affecting the muscles on one side of the face. It happens when the facial nerve, which controls these muscles, becomes inflamed or swollen and stops working properly. It is the most common cause of sudden one-sided facial weakness.

The face may droop on the affected side, making it hard to smile, close the eye, or move the eyebrow. Although the sudden onset can be frightening, Bell's palsy is not a stroke. However, because a stroke can cause similar facial drooping, it is important to be assessed urgently to be sure.

Symptoms usually come on quickly, over hours to a couple of days. One side of the face becomes weak or droops, the eye on that side may not close fully, and the mouth may sag, causing dribbling. Some people notice changes in taste, increased sensitivity to sound, pain around the jaw or ear, or a dry eye or mouth.

Seek emergency help straight away if facial weakness comes with sudden weakness or numbness in an arm or leg, slurred or difficult speech, a severe sudden headache, or drooping that affects only the lower face while the forehead still moves. These can be signs of a stroke, which needs immediate treatment. In Bell's palsy, the whole side of the face, including the forehead, is typically affected.

The exact cause is not always clear, but Bell's palsy is thought to be linked to swelling and inflammation of the facial nerve, often following a viral infection. Viruses associated with cold sores and other common infections may play a role.

It can affect anyone but is more common in people with diabetes and during pregnancy. It is not usually a sign of a serious long-term condition, and it does not normally run in families. Most people who have it do not have an obvious trigger.

Bell's palsy is usually diagnosed by examining the face and ruling out other causes. A doctor will check the pattern of weakness, including whether the forehead is affected, since Bell's palsy typically involves the whole side of the face, whereas a stroke often spares the forehead.

There is no single test for Bell's palsy. Because other conditions such as stroke, infections, or nerve problems can cause similar symptoms, the doctor may arrange further tests or scans if the picture is not typical, if recovery is slow, or if other symptoms are present. Urgent assessment is important so that a stroke is not missed.

A short course of steroid tablets is the main treatment and works best when started early, ideally within 72 hours of symptoms beginning. Steroids help reduce inflammation of the facial nerve and improve the chance of a full recovery. In some cases, antiviral medicine may also be considered.

Protecting the eye is essential if it will not close fully, as the surface can dry out and become damaged. This may involve lubricating eye drops during the day, ointment and taping the eye closed at night, and wearing glasses for protection. Facial exercises may be suggested as movement returns. Anyone with eye pain or worsening vision should be reviewed promptly.

Bell's palsy cannot be reliably prevented because its exact cause is not fully understood. The good news is that the outlook is usually positive. Most people start to improve within a few weeks and recover fully within a few months, especially when treatment begins early.

A smaller number of people have longer-lasting weakness or some residual changes in facial movement. If there is no sign of improvement after several weeks, or if symptoms worsen, further assessment is advised to look for other causes and consider additional support such as specialist rehabilitation.