Bell Palsy: Rapid Evidence Review

Bell palsy should be suspected in patients with acute onset of unilateral facial weakness or paralysis involving the forehead in the absence of other neurologic abnormalities. The overall prognosis is good. More than two-thirds of patients with typical Bell palsy have a complete spontaneous recovery. For children and pregnant women, the rate of complete recovery is up to 90%. Bell palsy is idiopathic. Laboratory testing and imaging are not required for diagnosis. When other causes of facial weakness are being considered, laboratory testing may identify a treatable cause. An oral corticosteroid regimen (prednisone, 50 to 60 mg per day for five days followed by a five-day taper) is the first-line treatment for Bell palsy. Combination therapy with an oral corticosteroid and antiviral may reduce rates of synkinesis (misdirected regrowth of facial nerve fibers manifesting as involuntary co-contraction of certain facial muscles). Recommended antivirals include valacyclovir (1 g three times per day for seven days) or acyclovir (400 mg five times per day for 10 days). Treatment with antivirals alone is ineffective and not recommended. Physical therapy may be beneficial in patients with more severe paralysis.