From the Guidelines
Bell's palsy is a condition causing temporary facial weakness or paralysis due to inflammation of the facial nerve, with the exact cause often unknown, but viral infections like herpes simplex or herpes zoster are believed to be common triggers, and treatment typically includes corticosteroids started within 72 hours of symptom onset to reduce inflammation and improve recovery chances. The condition is characterized by acute unilateral facial nerve paresis or paralysis with onset in less than 72 hours and without identifiable cause 1. Patients with Bell's palsy may experience dryness of the eye or mouth, taste disturbance or loss, hyperacusis, and sagging of the eyelid or corner of the mouth.
Causes and Prognosis
The causes of Bell's palsy are not fully understood, but it is thought to result from facial nerve inflammation and edema, which may lead to nerve compression and temporary or permanent nerve damage 1. The prognosis for Bell's palsy is generally good, with about 70-85% of patients recovering completely within 3-6 months without treatment 1. However, some patients may experience incomplete recovery with some residual weakness, and a small percentage may have severe, permanent facial weakness or develop synkinesis (involuntary muscle movements).
Treatment
Treatment for Bell's palsy typically includes corticosteroids like prednisone (60-80mg daily for 5-7 days, then tapered) started within 72 hours of symptom onset to reduce inflammation and improve recovery chances 1. Antiviral medications such as acyclovir (400mg five times daily for 7-10 days) or valacyclovir (1000mg three times daily for 7 days) may be added if herpes virus is suspected. Eye protection is crucial if the eye cannot close properly, using artificial tears during the day and lubricating ointment with eye patching at night to prevent corneal damage. Physical therapy, including facial exercises and massage, may help maintain muscle tone during recovery.
Key Points
- Bell's palsy is a condition causing temporary facial weakness or paralysis due to inflammation of the facial nerve.
- The exact cause is often unknown, but viral infections like herpes simplex or herpes zoster are believed to be common triggers.
- Treatment typically includes corticosteroids started within 72 hours of symptom onset to reduce inflammation and improve recovery chances.
- Antiviral medications may be added if herpes virus is suspected.
- Eye protection is crucial if the eye cannot close properly to prevent corneal damage.
- Physical therapy may help maintain muscle tone during recovery.
From the Research
Causes of Bell's Palsy
- The exact cause of Bell's palsy is unknown, but it is thought to be related to a viral infection or inflammation of the facial nerve 2, 3.
- Comorbidities such as diabetes, obesity, and pregnancy may be associated with an increased risk of developing Bell's palsy 3.
- The condition is characterized by an acute onset of unilateral, lower motor neuron weakness of the facial nerve in the absence of an identifiable cause 2.
Prognosis of Bell's Palsy
- Most patients with Bell's palsy will recover fully within six months, regardless of treatment 3.
- The prognosis is generally good, with up to 70% of patients expected to make a full recovery 4.
- However, up to 30% of patients may be left with potentially disfiguring facial weakness, involuntary movements, or persistent lacrimation 4.
Treatment Options
- Corticosteroids are the mainstay of treatment for Bell's palsy and should be initiated within 72 hours of symptom onset 2, 5.
- Antiviral therapy in combination with corticosteroid therapy may confer a small benefit and may be offered on the basis of shared decision making 2, 5.
- Acupuncture, physical therapy, and other complementary therapies may be safe and effective adjuncts to conventional treatment, but further research is needed to confirm their efficacy 4, 6.