Bell's palsy Health Article

Definition

Bell's palsy is a temporary form of facial paralysis that occurs with damage to the nerve that controls movement of the muscles in the face.

Alternative Names

Facial palsy; Idiopathic peripheral facial palsy

Causes, incidence, and risk factors

Bell's palsy is a form of cranial mononeuropathy VII. It is the most common type of this nerve damage. Bell's palsy affects about 2 in 10,000 people.

Bell's palsy involves damage to the seventh cranial (facial) nerve. This nerve controls the movement of the muscles of the face. The cause is often not clear, although herpes infections may be involved.

Bell's palsy is thought to be linked to swelling (inflammation) of the nerve in the area where it travels through the bones of the skull. Other conditions related to Bell's palsy include:

• Diabetes
• Lyme disease
• Sarcoidosis

Symptoms

Symptoms usually start suddenly, and range from mild to severe. They may include:

• Change in facial expression (for example, grimacing)
• Difficulty with eating and drinking
• Drooling due to lack of control over muscles of the face
• Droopy eyelid or corner of mouth
• Dry eye or mouth
• Face feels stiff or pulled to one side
• Facial paralysis of one side of the face, makes it hard to close one eye
• Headache
• Loss of sense of taste
• Pain behind or in front of the ear
• Sensitivity to sound (hyperacusis) on the affected side of the face
• Twitching in face
• Weakness in face

Signs and tests

• Blood tests for sarcoidosis or Lyme disease
• Magnetic resonance imaging (MRI)
• Electromyography (EMG)
• Nerve conduction test

Other causes of cranial mononeuropathy VII, such as head injury and tumor, need to be ruled out.