Bell palsy

James W Russell MD MS (Dr. Russell of the University of Maryland has no relevant financial relationships to disclose.)
Louis H Weimer MD, editor. (

Dr. Weimer of Columbia University has received consulting fees from Roche.

Originally released March 11, 1998; last updated September 9, 2020; expires September 9, 2023


The clinical article reviews the clinical presentation, diagnosis, pathogenesis, and management of Bell palsy. Bell palsy is an acute, usually unilateral mononeuropathy of the seventh cranial nerve. The disorder is presumed to be inflammatory and associated with 1 of several different viral etiologies, usually herpes simplex virus-1. The disorder is usually self-limiting, with up to 90% of affected subjects showing full recovery. Recovery occurs primarily within 4 to 6 months of onset of the disorder. The differential diagnosis is outlined in this clinical article, and specific tests may be indicated for certain patients depending on the clinical evaluation. Early treatment with steroids is recommended. Several large randomized studies clearly show that prednisone (prednisolone), given within 48 hours of onset of the palsy, improves recovery rate and promotes early recovery in affected patients. Combination therapy with antivirals is not recommended based on current clinical trial and metaanalysis data. In addition, supportive care and eye care are critical.

Historical note and terminology

Bell palsy was named for Sir Charles Bell (1774-1842), a British neurologist, who in 1821 described the condition and demonstrated that there was a separation of motor and sensory innervation in the face. Similar descriptions of the disorder were, however, previously published by Nikolaus A Friedreich (1825-1882) in 1798 and Richard Powell in 1813.

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