Bell's palsy afflicts approximately 40,000 Americans each year. It affects men and women equally, and can occur at any age, but it is less common before age 15 or after age 60.
Symptoms of Bell's palsy usually begin suddenly and reach their peak within 48 hours. They range in severity from mild weakness to total paralysis, and may include:
- Twitching, weakness, or paralysis on one or both sides of the face
- Drooping eyelid or corner of the mouth
- Dry eye or mouth
- Impairment of taste
- Excessive tearing in the eye.
The condition often causes significant facial distortion.
Most Bell's palsy research scientists believe that a viral infection, such as viral meningitis or the common cold sore virus (herpes simplex), causes the condition when the facial nerve swells and becomes inflamed in reaction to the infection.
Several medical conditions associated with the disorder include:
- Influenza or a flu-like illness
- Chronic middle ear infection (otitis media)
- High blood pressure (hypertension)
- Lyme disease
- Trauma, such as skull fracture or facial injury.
(Click Causes of Bell's Palsy for more information.)
In order to make a Bell's palsy diagnosis, a healthcare provider will ask a number of questions, perform a physical exam, and recommend certain tests. The healthcare provider will also rule out other causes of facial paralysis. There is no specific laboratory test to confirm a diagnosis of Bell's palsy.
To help see the amount of damage and rule out other possible causes of facial paralysis, a healthcare provider may recommend the following tests:
- MRI (magnetic resonance imaging)
- CT scan.