BELL’S PALSY – Causes and Risk Factors, Clinical Manifestations, Diagnostic Evaluations and Management

Bell’s palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side. Damage to this nerve causes weakness or paralysis of these muscles.

Bell’s palsy is defined as an idiopathic unilateral facial nerve paralysis, usually self-limiting. Named after Scottish anatomist Charles Bell, who first described it, Bell’s palsy is the most common acute mononeuropathy (disease involving only one nerve) and is the most common cause of acute facial nerve paralysis.



The etiology is unknown; it may be the result of  an inflammatory process. A type of herpes infection called herpes zoster might be involved. Other viruses that have been linked to Bell’s palsy include: the virus that causes chickenpox and shingles (herpes zoster), the virus that causes mononucleosis (Epstein-Barr) and another virus in the same family (cytomegalovirus).

Other conditions that may cause Bell’s palsy include:

  • Brain tumor
  • Stroke
  • Lyme disease
  • HIV infection
  • Middle ear infection
  • Sarcoidosis


Sometimes patient may have a cold shortly before the symptoms of Bell’s palsy begin. Symptoms most often start suddenly, but may take 2-3 days to show up. They do not become more severe after that. Symptoms are almost always on side only. They may range from mild to severe. The face will feel stiff or pulled to one side, and may look different. Other symptoms can include:

  • Difficulty eating and drinking; food falls out of one side of the mouth
  • Drooling due to lack of control over the muscles of the face
  • Drooping of the face, such as the eyelid or corner of the mouth
  • Hard to close one eye
  • Problems smiling, grimacing, or making facial expressions
  • Twitching or weakness of the muscles in the face
  • Dry eye or mouth
  • Headache
  • Loss of sense of taste
  • Sound that is louder in one ear (hyperacusis)
  • Twitching in face



No specific laboratory test can confirm a diagnosis of Bell’s palsy. Often, Bell’s palsy can be diagnosed just by taking a health history and doing a complete physical exam. History of the onset of symptoms is used to diagnose Bell’s palsy. Observation of the patient confirms the diagnosis. An EMG may be done. The possibility of a stroke is ruled out.

  • CT scan of the head
  • Magnetic resonance imaging (MRI) of the head
  • Electromyography (EMG)
  • Nerve conduction test



Most people with Bell’s palsy recover fully with or without treatment. But doctor may suggest medications or physical therapy to help speed recovery.

Study results have been mixed regarding the effectiveness of two types of drugs commonly used to treat Bell’s palsy: corticosteroids and antiviral drugs. Corticosteroids, such as prednisone, are powerful anti-inflammatory agents. If they can reduce the swelling of the facial nerve, it will fit more comfortably within the bony corridor that surrounds it. Antiviral drugs, such as acyclovir or valacyclovir, may stop the progression of the infection if a virus is known to have caused it. Analgesics are given for pain control. Moist heat with gentle massage to the face and ear also eases pain. Use of a facial sling aids in eating and supports facial muscles.

Surgery is rarely an option for Bell’s palsy. One way to relieve the pressure on the facial nerve is to surgically open the bony passage through which it passes. This decompression surgery is controversial and rarely recommended. In some cases, however, plastic surgery may be needed to make your face look and work better.

Botulinum toxin (Botox) injections can be used to treat either the affected or the unaffected side of the face in people with long-term Bell’s palsy. Eye drops or eye ointment as ordered by the physician and a patch are used to protect the eye. Facial exercises several times a day prevent muscle atrophy. Use of a facial sling aids in eating meals and prevents atrophy. A nutritious, well balanced diet in a consistency the patient can tolerate is important to maintain nutritional status.


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BELL’S PALSY – Causes and Risk Factors, Clinical Manifestations, Diagnostic Evaluations and Management

BELL’S PALSY – Causes and Risk Factors, Clinical Manifestations, Diagnostic Evaluations and Management