Brain & Nervous System Stroke Symptoms What Is Bell's Palsy? By Heidi Moawad, MD Heidi Moawad, MD Facebook LinkedIn Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications. Learn about our editorial process Updated on February 06, 2022 Medically reviewed by Huma Sheikh, MD Medically reviewed by Huma Sheikh, MD Facebook LinkedIn Twitter Huma Sheikh, MD, is a board-certified neurologist, specializing in migraine and stroke, and affiliated with Mount Sinai of New York. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents Symptoms Causes Diagnosis Treatment A Word From Verywell Bell's palsy is a condition that causes partial or complete weakness of one side of the face. The symptoms of Bell’s palsy, such as a sagging eyebrow or drooping mouth corner, develop pretty quickly and can dramatically change one's appearance. Symptoms of Bell's palsy usually improve on their own within a few months. Corticosteroids are typically prescribed to optimize a person's chance for a full recovery. Verywell / JR Bee Bell's Palsy Symptoms The symptoms of Bell's palsy usually come on suddenly (over a few hours) and typically worsen over the course of a few days before stabilizing. Bell's palsy affects one side of the face. It can cause partial or complete facial weakness, including in the forehead, eyelid, cheek, and mouth. Common findings on the affected side include: A sagging eyebrowDisappearance of the nasolabial fold (so-called "smile line")Drooping of the corner of the mouth In addition, Bell’s palsy can cause difficulties with eating and drinking, and patients may notice some drooling. Problems with the ability to taste food may also occur. A person's speech can also sound a bit slurred due to difficulty controlling the muscles of their mouth. Bell's palsy can also cause dryness and even redness of the eye due to decreased blinking, incomplete eyelid closing, and diminished facial tears. Lastly, some people with Bell’s palsy experience ear discomfort with loud noises (i.e., hyperacusis). For most people, symptoms of Bells palsy resolve within two weeks to a few months. Sometimes, after an episode of Bell's palsy is largely resolved, a person may continue to have slight weakness of their face that can last for years. Causes Bell's palsy is more common in adults than in children, and it is not a sign of any serious health problem. It is a peripheral neuropathy (nerve disease) of the facial nerve, which is the seventh cranial nerve. This nerve comes off the brain stem and controls facial movement. When the facial nerve is inflamed and swollen (as in Bell's palsy), it cannot properly communicate with the facial muscles, which leads to weakness. Sometimes, Bell's palsy is triggered by a viral infection, like the herpes simplex virus (HSV). Diabetes and pregnancy have also been associated with a higher incidence of Bell's palsy. But most of the time, it is impossible to pinpoint the exact cause of the condition, and so the "why" behind a person's Bells palsy is often considered idiopathic (without a known cause). Diagnosis Bell's palsy is usually diagnosed based on a person's symptoms and a physical exam. That said, Bell's palsy is generally considered a diagnosis of exclusion, meaning additional diagnostic studies are often needed to rule out other mimicking conditions. Some of these possibilities are very serious, so referral to a neurologist or otolaryngologist as soon as possible is warranted. The following are some tests that might be done. Physical Exam If one side of your face is weak, your healthcare provider will examine you to check for serious, brain-related causes of facial weakness, such as a stroke. The good news is that there are some distinct physical exam characteristics of Bell's palsy that differentiate it from facial weakness caused by a problem in the brain. Peripheral Nervous System Involvement (e.g., Bell's Palsy) Weakness of the lower and upper parts of the face Loss of forehead movement Central Nervous System Involvement (e.g., Stroke) Weakness of the lower part of the face Preserved forehead movement This distinction is due to the way nerves run from the brain to the face. Basically, your forehead receives connections from both sides of the brain, whereas the lower part of the face receives connections from just one side of the brain. This means that a person with a problem in the brain (stroke) would have preserved forehead movement while a person with a problem with the facial nerve (Bell's palsy) would have a loss of forehead movement. In the end, while Bell's palsy is not as serious a condition as brain disorders that can cause similar symptoms, the facial weakness with Bell's is usually more severe. Bell's Palsy vs. Stroke: What Are the Differences? Ear Exam Since one-sided facial weakness may result from a bacterial infection of the middle ear, or as a complication of herpes zoster infection (shingles)—called Ramsay Hunt syndrome—your healthcare provider will also examine your ear. Imaging Tests Various imaging tests, such as brain magnetic resonance imaging (MRI) and computed tomography (CT scan), can be helpful in teasing out alternative diagnoses like stroke, tumor, multiple sclerosis, and an uncommon inflammatory disease called sarcoidosis. Blood Tests Sometimes blood tests are warranted to rule out other causes of facial paralysis, most commonly Lyme disease and less commonly, HIV infection or an autoimmune disease like Sjögren's syndrome. Electromyography (EMG) For people with more severe cases of Bell's palsy, such as complete paralysis of the facial nerve, a healthcare provider may recommend an electromyography (EMG) to help predict prognosis and/or provide guidance on a treatment plan. Much of the time, weakness of one side the face turns out to be Bell's palsy. But it is important for you to know that weakness of the face can be a stroke or another neurological condition, so seek medical attention without delay. Treatment While there is no medication or therapy that can cure Bell's palsy, corticosteroids (e.g., prednisone) have been found in various studies to improve both speed of recovery and chances for a full recovery. An antiviral medication, such as Valtrex (valacyclovir), is sometimes prescribed along with corticosteroids for the treatment of Bell's palsy. However, the effectiveness of antiviral therapy for this purpose is highly debated, as most studies show no benefit compared with placebo. Eye Care One major concern associated with Bell's palsy is the affected eye. Due to incomplete eyelid closure and impaired tear production in that eye, the eyeball can become dry, red, or itchy. This is why those with Bell's palsy should use artificial tears, which are available over the counter. Your healthcare provider may also recommend using an eye patch at night to prevent irritation. Complementary Therapies A few different complementary therapies, such as electrical nerve stimulation, acupuncture, and facial exercises, may also be useful in the management of Bell's palsy, although research backing these therapies is scant. A Word From Verywell If any part of your face becomes weak or droopy, you should see a medical professional right away—even if it seems that you have a classic Bell's palsy presentation. Your symptoms could be caused by a variety of neurological conditions, and it is important to exclude the serious ones. Conditions That Can Cause Stroke-Like Symptoms 7 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. National Institutes of Health. Bell’s palsy fact sheet. MedlinePlus. Bell palsy. Pavlidis P, Cámara RJA, Kekes G, Gouveris H. Bilateral taste disorders in patients with Ramsay Hunt syndrome and Bell palsy. Ann Neurol. 2018 Apr;83(4):807-815. doi:10.1002/ana.25210 De Seta D, Mancini P, Minni A, et al. Bell’s palsy: Symptoms preceding and accompanying the facial paresis. ScientificWorldJournal. 2014;2014:801971. doi:10.1155/2014/801971 Jeon Y, Lee H. Ramsay Hunt syndrome. J Dent Anesth Pain Med. 2018;18(6):333-337. doi:10.17245/jdapm.2018.18.6.333 Yoo HW, Yoon L, Kim HY, et al. Comparison of conservative therapy and steroid therapy for Bell's palsy in children. Korean J Pediatr. 2018;61(10):332-337. doi:10.3345/kjp.2018.06380 Holland NJ, Bernstein JM. Bell's palsy. BMJ Clin Evid. 2014;2014:1204. Additional Reading Albers JR, Tamang S. Common questions about Bell palsy. Am Fam Physician. 2014 Feb 1;89(3):209-12. https://www.aafp.org/afp/2014/0201/p209.html Maller T, Goldenstein S, Ronen O. Prevalence and characteristics of hearing loss in patients diagnosed with Bell's palsy. Eur Arch Otorhinolaryngol. 2018 Jan;275(1):99-102. doi:10.1007/s00405-017-4816-0. Epub 2017 Nov 21. Salinas RA, Alvarez G, Daly F, Ferreira J. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2010 Mar 17;(3):CD001942. doi:10.1002/14651858.CD001942.pub4 Zandian A, Osiro S, Hudson R, et al. The neurologist’s dilemma: A comprehensive clinical review of Bell’s palsy, with emphasis on current management trends. Med Sci Monit. 2014;20:83-90. doi:10.12659/MSM.889876 By Heidi Moawad, MD Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit