A temporary weakening or paralysis of facial muscles could indicate a condition known as Bell’s palsy. There are 12 pairs of cranial nerves that connect the human brain to different parts of the head, neck, and the rest of the body. These nerves provide blood supply to the eyes, nose, face, tongue, shoulders, and other vital body parts. Damage to any of these nerves can affect the functioning of that specific body part. Bell’s palsy is a result of damage to the 7th cranial nerve - the facial nerve.

Also known as idiopathic facial palsy, Bell’s palsy leads to temporary paralysis or weakness of the facial muscles on one side of the face. It causes difficulty in blinking or closing the eyes and controlling facial expressions such as smiling. Bell’s palsy can affect both men and women and is more commonly seen in people between the age group of 15 to 60 years.

What are the early signs of Bell’s palsy?

The symptoms of Bell’s palsy gradually increase and reach the peak of severity within 48 to 72 hours. Some of the common early signs include:

• Pain behind the ear
• Facial numbness
• Slight fever
• Disappearance of the facial creases and the fold between the nose and the lip (nasolabial fold)
• Flat expressionless face
• Unfurrowing of the forehead
• Drooping of the corner of the mouth
• Inability to close the eyelids 
• Eyes roll upwards while trying to close the eyelids (Bell's phenomenon)
• Sagging of the lower eyelids
• Dryness and inflammation of the eyes
• Rolling of tears down the eyes followed by the reduced tear production
• Drooling from the corner of the affected side of the mouth
• Slurred speech
• Loss of taste
• Inability to chew food, spilling of food from the corner of the mouth
• Headache
• Ringing sensation in the ear (tinnitus).

One must consult a doctor immediately in the presence of any of the symptoms listed above.

What causes Bell’s palsy?

The exact cause of Bell’s palsy is not known. Several theories that have been associated with the cause of Bell’s palsy include:

• Viral infections caused due to herpes simplex, herpes zoster, Epstein-Barr, coxsackievirus, cytomegalovirus, mumps, rubella, or influenza B virus.
• Weakened immunity due to stress, lack of sleep, physical trauma, or autoimmune diseases.
• Response to an infection, which increases pressure in the fallopian canal (a canal that carries the nerve supplying to the side of the face), resulting in restricted blood and oxygen flow to the facial nerve.
• Damage to the fatty covering of the nerves (myelin sheath).

Scientists have found that Bell’s palsy can also occur due to some critical medical conditions such as a stroke, brain tumour, myasthenia gravis (an autoimmune condition), and Lyme disease (an infectious disease).

Who is at risk for developing Bell’s palsy?

Anyone can suffer from facial paralysis. However, factors that may increase the risk of developing the condition include:

• Family history of Bell’s palsy
• Obesity
• High blood pressure (hypertension)
• Pregnancy 
• Preeclampsia (pregnancy complication)
• Diabetes 
• Upper respiratory tract infections
• Autoimmune diseases such as myasthenia gravis and Sjögren's syndrome 
• Viral infections such as cold sores (herpes simplex virus), mononucleosis (Epstein-Barr virus), and shingles (herpes zoster virus).

How is Bell’s palsy treated?

The treatment of Bell’s palsy includes: 

• Oral medications: Corticosteroids such as prednisone are given to the patient to reduce the swelling of the affected nerve and regain the facial movements quicker. Antiviral medications such as acyclovir and valacyclovir are given to treat viral infection and accelerate the healing process.
• Eye care: Eye drops and artificial tears may be prescribed to reduce the irritation, dryness, and pain in the eyes. An eye patch may also be recommended to protect the constantly open eye from irritants and injuries.
• Surgery: Surgery is advised only if the condition does not improve with medications or worsens even after 3 months.
  • Decompression surgery: In this surgery, the doctor releases pressure from the affected nerve.
  • Functional facial plastic surgery: In this procedure, the doctor corrects the facial asymmetry and provides assistance for the closure of the eyelid.

Around 80% of the people suffering from Bell’s palsy start improving by the 3rd week and recover completely within 3 to 9 months. However, one must consult a doctor immediately, if:

• The face droops suddenly on 1 side
• The person is unable to lift the arms or maintain balance
• The person has slurred or garbled speech.

These could be signs of a stroke that requires immediate medical attention.

Conclusion

Bell’s palsy causes temporary weakening or paralysis of facial muscles resulting in drooping of half the face. This usually results due to a pinched facial nerve or a viral infection. This condition is usually not life-threatening and resolves on its own within a few months. However, medical advice must be sought if the symptoms persist and to rule out other causes of facial paralysis, e.g stroke.

If you experience any symptoms of Bell’s palsy:

Consult a Neurologist