Bell’s Palsy is thought to be due to viral inflammation around the facial nerve as it travels within the base of the skull1. It is the most common cause of facial paralysis. Note that Bell’s Palsy specifically refers to acute facial paralysis after the exclusion of other diagnoses. It is a misnomer to refer to all cases of facial paralysis as “Bell’s Palsy.”
The diagnosis of Bell’s Palsy is usually a clinical diagnosis. This means a physician will make the diagnosis after a history and physical exam are performed in order to exclude other possible causes of facial paralysis, such as stroke or trauma. Blood tests or imaging (such as an MRI) may be required in certain cases in order to exclude other potential causes of acute facial paralysis.
Treatment of Bell’s Palsy involves taking a brief course of oral steroids, and may include an oral antiviral medication as well. Typically, patients who are promptly treated for Bell’s palsy recover facial movement. Prognosis for recovery in Bell’s Palsy is generally quite good, as evidenced by the fact that 70% of untreated patients recover to normal or near-normal function2. With the addition of medical therapy, recovery appears to improve to 90-95% of appropriately treated patients3,4. Some patients with severe Bell’s palsy may benefit from facial nerve decompression surgery. The need for this surgery is determined by electrodiagnostic testing (electroneuronography and electromyography) within the first three weeks of diagnosis, and in-depth consultation with a lateral skull base surgeon (please see “Electrodiagnostic testing” under “Programs”).
After recovery from Bell’s Palsy, some patients may notice unwanted facial movement or muscle spasms, or facial discomfort. These may be signs of synkinesis and can be improved through treatment.
 Baugh, R.F., et al., Clinical Practice Guideline Bell’s Palsy. Otolaryngology--Head and Neck Surgery, 2013. 149(3 suppl): p. S1-S27
 Peitersen E. Bell's palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Oto-Laryngologica. 2002 Jan 1;122(7):4-30.
 Sullivan FM, Swan IR, Donnan PT, Morrison JM, Smith BH, McKinstry B, Davenport RJ, Vale LD, Clarkson JE, Hammersley V, Hayavi S. Early treatment with prednisolone or acyclovir in Bell's palsy. New England Journal of Medicine. 2007 Oct 18;357(16):1598-607.
 Hato, N., et al. (2007). "Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study." Otology & neurotology 28(3): 408-413.