Bell’s palsy, or idiopathic facial nerve palsy, refers to the isolated paralysis of the facial muscles on one or both sides. It is of unclear cause, though damage to the seventh cranial, or FACIAL NERVE, possibly of viral origin, is thought likely. Occurring in both sexes at any age, it presents with a facial pain on the aﬀected side, followed by an inability to close the eye or smile. The mouth appears to be drawn over to the opposite side, and ﬂuids may escape from the angle of the mouth. Lines of expression are ﬂattened and the patient is unable to wrinkle the brow. Rare causes include mastoiditis, LYME DISEASE, and hypertension.
Treatment Oral steroids, if started early, increase the rate of recovery, which occurs in over 90 per cent of patients, usually starting after two or three weeks and complete within three months. Permanent loss of function with facial contractures occurs in about 5 per cent of patients. Recurrence of Bell’s palsy is unusual.