Causes of Facial Nerve Disorders

UW Health's Facial Nerve Clinic at UW Hospital and Clinics in Madison, Wisconsin, provides a multidisciplinary approach to diagnosing and treating facial paralysis in children and adults.


Here are some of the causes for the conditions we treat:

Bell's Palsy


Bell's palsy is a condition that causes the facial nerve to stop working. Facial muscles become weak or paralyzed. The onset of Bell's is rapid, meaning it usually occurs in less than 72 hours. If the drooping occurs over weeks or months, it is not Bell's palsy.


The paralysis from Bell's palsy can appear as sagging, frozen expressions, frowns, drooping or other unusual expressions and affects the entire half of the face. The Bell's palsy diagnosis is reserved for sudden onset facial paralysis, once all other causes have been excluded. Bell's palsy on both sides of the face is extremely rare. Most - but not all - patients with Bell's palsy will have complete return of normal facial function.


The true cause of Bell's palsy is unknown. Paralysis occurs when the nerve becomes damaged, compressed or swollen. Researchers believe a potential link exists between Bell's and viral infections or that Bell's could be a response from the body's immune system. Additionally, women who are pregnant seem to be at an increased risk.


Lyme Disease


Lyme disease is caused by tics, making people who spend time in wooded areas particularly susceptible. If a tic infects an individual carrying a certain type of bacteria, this can sometimes cause Lyme disease. The risk of Lyme disease is greatest in Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island and Wisconsin.


Learn more about Lyme disease


Symptoms usually begin one to two weeks after a tick bite, and will progress if not treated. The infection can be observed initially by a rash. If left untreated, the bacteria can continue, causing pain and swelling of the joints resembling arthritis. If the infection is able to progress far enough, neurologic symptoms such as facial paralysis can occur.


Your provider may do a laboratory test that looks for markers of the bacteria that causes Lyme disease. However, the rash associated with Lyme disease is so unique that, if your provider is aware that you have been in a region where exposure would occur, the presence of the rash is enough for a diagnosis. Lyme disease can be treated successfully with oral medications.




Stroke presents with speech difficulties or any other weakness or numbness anywhere in the body, and you should call 9-1-1 immediately if you notice these symptoms. Weakness of one side of the face that does not include the upper face, or the forehead, may be a sign of a stroke, as well.


Parotid/Acoustic/Skull Base Tumor Surgery


Tumors in the parotid gland can sometime sometimes result in facial paralysis prior to surgery, and surgical treatment for parotid and skull base tumors can result in facial paralysis. During surgery, surgeons often intentionally stretch or cut the facial nerve to remove all cancerous cells. In some procedures, surgeons can graft a damaged facial nerve to restore normal nerve function. But in cases in which facial dysfunction remains, referral to the Facial Nerve Clinic may be warranted.




Facial paralysis can result from head trauma, which could result from swelling or severing of the facial nerve.


Viral Infection


Facial weakness with a blistering rash around or in the ear may indicate a zoster infection (shingles) causing inflammation (irritation) of the facial nerve.




The Facial Nerve Clinic can evaluate children born with a facial nerve problem, referred to as congenital facial paralysis.