Bell's palsy is a condition in which the muscles of the face become paralyzed due to damage to a facial nerve. Potential causes of Bell's palsy include viral infections (herpes simplex, HIV), bacterial infections (tuberculosis, Lyme disease), brain stem tumors, skull fractures or neurological complications from chronic illnesses, such as diabetes, according to the Neurology Channel. Symptoms may range in severity from mild facial weakness to complete paralysis, depending on the extent of nerve damage.
Warning Symptoms
Although the symptoms of Bell's palsy typically develop suddenly, associated signs of illness sometimes occur just prior to the onset of facial muscle disturbance. According to the Neurology Channel, many people feel pain behind the ear or in the back of the head several hours before signs of weakness begin to appear in the face. Additionally, in roughly 60 percent of cases, individuals who develop Bell's palsy are still recovering from a recent viral or upper respiratory infection.
Common Symptoms
The most common symptoms of Bell's palsy are facial weakness or paralysis, dry eyes or mouth (due to decreased saliva and tear production) and problems tasting, according to the Neurology Channel. The upper and lower parts of only one side of the face are usually affected, with fewer than 1 percent of cases experiencing symptoms on both sides of the face. Facial muscles may twitch or droop, and affected individuals may have problems making voluntary facial expressions. Pain in the ear or behind or in front of the ear on the affected side may also occur. Sounds may seem louder in the affected ear.
Other symptoms that may develop include drooling, headache, impaired speaking, dizziness, hypersensitivity to sound and problems with the eye that include difficulty blinking, closing the eye or producing tears.
Even without treatment, these symptoms disappear within a few days or months in the majority of patients; however, 7 to 10 percent of patients experience a recurrence of these symptoms, according to the Neurology Channel.
Serious Symptoms
According to MedlinePlus, 60 to 80 percent of Bell's palsy cases go away within a few months. However, the remainder are characterized by serious and potentially permanent symptoms. These symptoms include disfigurement and permanent change in the appearance of the face due to loss of movement, chronic problems with taste, long-term spasms of facial muscles or the eyelids, and the development of eye infections or corneal ulcers. Synkinesis--abnormal involuntary muscle movement that accompanies a voluntary facial movement--may also occur. Synkinesis develops as a result of mistaken regrowth of nerve fibers and can cause people to exhibit tears when laughing, or closing an eye on the affected side when smiling.
