Bell’s palsy, also known as facial palsy, is a condition that causes sudden weakness in the facial muscles. It makes the face appear droopy while the smile is one-sided and the eye on the affected side resists closing.
The exact cause is undetermined; however, it may be the result of swelling and inflammation of the nerve that controls the muscles on one side of the face. It also may occur as a reaction to a viral infection. In rare cases facial palsy can affect the nerves on both sides of the face.
Bell’s palsy is usually temporary with complete recovery in approximately 6 months. In rare cases the condition can recur or cause lifelong symptoms.
Symptoms of Bell’s palsy include:
- Sudden onset of weakness to total paralysis on one side of the face (within hours to days)
- Facial droop and difficulty making facial expressions
- Pain around the jaw or in or behind the ear on the affected side
- Decreased ability to taste
- Increased sensitivity to sound on the affected side
- Variations in the amount of tears and saliva produced
The exact cause of Bell’s palsy is unknown but it is often associated to exposure to a viral infection. Viruses related to Bell’s palsy include:
- Herpes simplex (cold sores and genital herpes)
- Herpes zoster (chickenpox and shingles)
- Epstein-Barr (mononucleosis)
- Cytomegalovirus infections
- Rubella (German measles)
- Adenovirus (respiratory disease)
- Mumps virus (mumps)
- Influenza B (flu)
- Coxsackie virus (hand, foot and mouth disease)
Risk factors for Bell’s palsy include:
- Pregnancy (during the third trimester or in the first week after childbirth)
- Upper respiratory infection (flu or the cold)
- Genetic predisposition (recurrent episodes of Bell’s palsy can be the result of family history of the condition)
Complications that arise from Bell’s palsy include:
- Irreversible damage to the facial nerve.
- Partial or complete blindness of the eye on the affected side due to excessive dryness and scratching of the cornea.
- Misdirected regrowth of nerve fibers that can cause synkinesis (involuntary contraction of certain muscles when trying to move others).