By Dr. Mercola
The main cause of Bell’s palsy is inflammation or compression of the seventh cranial nerve responsible for facial muscle control. But for the nerve to become inflamed, there are various factors involved, which you will discover below.
Microbial Diseases Can Lead to Bell's Palsy
Experts generally agree that Bell’s palsy is caused by various microbes entering the cranial nerve. The table below outlines a few examples:1
✓ Cold sores and genital herpes (herpes simplex virus)
✓ Chickenpox (varicella zoster) and shingles (herpes zoster)
✓ Mononucleosis (Epstein-Barr)
✓ Cytomegalovirus infections (Herpesviridae family)2
✓ Respiratory illnesses (adenovirus)
✓ German measles (rubella)
✓ Mumps (mumps virus)
✓ Flu (influenza B)
✓ Hand-foot-and-mouth disease (coxsackievirus)
What Are the Risk Factors of Bell's Palsy?
Since Bell’s palsy can be caused by various bacteria and viruses, there’s a chance that you can develop it if you have an ongoing infection, such as the flu or a cold. The microbe can enter your Fallopian canal, causing inflammation and temporary paralysis. Other factors that can put you at risk of Bell’s palsy include:4,5,6
✓ A lung infection
✓ Family history of Bell’s palsy
✓ Multiple sclerosis
✓ High blood pressure
✓ Injury to the cranial area
It’s estimated that for every 100,000 people, 15 to 30 new cases of Bell’s palsy are diagnosed every year. Both men and women are equally affected by it, and the risk increases once you reach the age of 40. If you or someone you know has had Bell’s palsy before, there’s an 8 percent chance that you can get it again.7
Which Parts of the Face Are Affected by Bell's Palsy?
Depending on the damage of the cranial nerve, the areas affected by Bell’s palsy can include one or both sides of the face, as well as the eyelids and ears. Some people’s sense of taste and tear production may also be affected.8
Complications Caused by Bell's Palsy
Mild cases of Bell’s palsy typically clear within a few weeks. However, some people are not as fortunate, and may develop complications such as:
• Permanent damage: The cranial nerve may suffer permanent damage as a result of the inflammation, preventing the return of normal facial function.
• Eye problems: If the inflammation affects eye function, there’s a chance that the affected eye can experience dryness and infection.
• Synkinesis: This is a condition where facial nerves are repaired but do not follow their original pattern. This causes involuntary contraction of certain muscles when performing certain actions.
The Causes of Bell's Palsy Are Different From the Causes of Stroke
Stroke commonly causes some form of paralysis,9 which is why Bell’s palsy is sometimes thought to be a form of stroke. However, it’s important to note that the paralysis caused by Bell’s palsy is due to an inflammation of the cranial nerve and only affects the facial area.10
On the other hand, a stroke occurs when blood flow to a part of the brain is cut off, leaving the affected brain cells to die, resulting in memory and muscle problems.11 There’s a large chance you can develop paralysis in any part of your body, and the damage can be mild or severe.12