Author: Paige Kalika, DO
University of Miami Health System 

Reviewed: March 2022

SUMMARY

Bell’s palsy is facial weakness that appears suddenly or rapidly and that has no known cause. Symptoms of Bell’s palsy typically get more severe over a few hours or a day or two. Bell’s palsy usually affects just one side of the face but can, in rare cases, affect both sides at the same time. The most common symptoms are: 

• An inability to raise the eyebrow 
• An inability to close the eyelid completely 
• A drooping of the corner of the mouth 

 The direct cause of Bell’s palsy is damage to a facial nerve. This can be triggered by an infection or, in rare cases, by leukemia or an autoimmune condition like sarcoidosis. The exact cause of Bell’s palsy is often unknown. The majority of children recover or show significant improvement within 4 to 6 weeks. Most people show at least some recovery by 6 months. 

Disorder Overview

DESCRIPTION

Bell’s palsy is the most common cause of acute, spontaneous paralysis of the face. It is acute because it does not last a long time. It is spontaneous because it appears suddenly and without warning. Paralysis refers to an inability to use muscles. 

Children with Bell’s palsy develop paralysis or weakness of the muscles of the face. This usually happens on just one side of the face. The child may have difficulty raising that eyebrow, closing that eyelid, and controlling that side of the mouth. They may drool or have trouble drinking from a straw. 

There are two forms of Bell’s palsy: 

• Incomplete. Most children have an “incomplete” Bell’s palsy. This means one of two things. First, it can mean that not all of the muscles are affected. Second, it can mean that they can still move the affected muscles a little. They may only have subtle weakness of the eyebrow, eyelid, and mouth. 

• Complete. Some children have a “complete,” or more severe, Bell’s palsy. This means they cannot move the affected muscles of the face at all. These children may not be able to raise an eyebrow, close an eye, or control that side of the mouth whatsoever. 

Bell’s palsy is usually not dangerous and cannot cause death.

SIGNS AND SYMPTOMS

The most common symptoms of Bell’s palsy are weakness of the muscles controlling the eyebrow, eyelid, and mouth on one side of the face. Other common symptoms include: 

• Dry eyes 
• Pain behind the ear on the affected side 
• Loss or change of taste sensation 
• An increased sensitivity to sounds (hyperacusis) 

If a child has a very mild case of Bell’s palsy, it is possible that no one notices the very subtle facial weakness.  

Most symptoms improve within 4 to 6 weeks, and almost all children have at least some recovery by 6 months. If there is no significant improvement at 4 months, a child’s doctor may do more testing to look for another cause of facial weakness. 

CAUSES

Bell’s palsy is not caused by a parent’s actions. It is not hereditary. It happens when something affects the facial nerve, the nerve that controls the muscles of the face.  

Damage to the Facial Nerve 

Bell’s palsy is caused by damage or inflammation of the facial nerve. Something may irritate the nerve and make it swell up. Because the nerve passes through a narrow bony canal in the skull, when the nerve swells, it presses against the hard surface of the skull. This injures the nerve. When the nerve is injured, it can’t send the necessary signals to the muscles of the face. The affected muscles become weak and can’t move well, if at all. 

Underlying Infection 

Most of the time, this damage or inflammation of the facial nerve is due to an infection.  

Common viruses that affect the facial nerve include: 

• Herpes simplex virus (HSV) 
• Cytomegalovirus (CMV) 
• Epstein-Barr virus (EBV) 
• Adenovirus 
• Varicella (chickenpox) 
• Rubella 
• Mumps 
• Influenza B 
• Echovirus 
• Coxsackievirus 

Common bacterial infections that affect the facial nerve include: 

• The bacteria causing ear infections 
• The bacteria involved with Lyme disease 

In rare cases, Bell’s palsy is associated with HIV infection, sarcoidosis, leukemia, or severe high blood pressure.  

While most cases of Bell’s palsy are due to viruses, doctors are usually not able to pinpoint which virus or exactly why it was triggered. Testing is sometimes necessary. Testing can rule out other causes or more dangerous causes of facial nerve weakness. This is important because other causes may require different treatment.

DIAGNOSIS AND LABORATORY INVESTIGATIONS

Bell’s palsy can be diagnosed by a doctor who recognizes its pattern of facial weakness. The doctor may sometimes order images of the brain to make sure that the facial weakness was not caused by a stroke, brain tumor, or infection. However, this is not always needed.

There are some important lab investigations that can help doctors better understand a case of Bell’s palsy. These include brain imaging, blood and spinal fluid tests, and tests for electricity in the muscles.

TREATMENT AND THERAPIES

Length of Treatment 

Steroids and antivirals are usually given for 5 to 10 days. 

Eye care is usually continued for as long as the child has eye symptoms. 

Untreated Bell’s Palsy 

Most children with Bell’s palsy will get better on their own, with or without treatment. However, children who are given steroids may recover more quickly and more completely.

Skipping eye drops and poor eye care at night may lead to eye injuries that need to be treated by an eye doctor. 

OUTLOOK

With treatment, the outlook for children with Bell’s palsy is excellent. At least 90% of children recover completely, often within 4 to 6 weeks. Even children who do not have a complete recovery usually regain some or most of the function of the muscles of the face within 6 months.  

Impact on Everyday Activities 

The child will need good eye care and may have trouble drinking through a straw and eating soup until symptoms improve. 

The child may need to use eye drops during the school day. It may be helpful to keep teachers and the school nurse informed about the child’s condition. 

Synkinesis 

Sometimes, when the facial nerve is severely affected, it grows back in a disorganized fashion. That means that the nerve signals controlling the muscles of the face may get mixed up. This can cause: 

• The mouth to twitch with blinking 
• The eye to wink when smiling 
• An eye tearing during saliva production 

This is called synkinesis. It may be mild. If it is severe, botulinum injections may be helpful. 

Incomplete Recovery 

A small percentage of children have incomplete recovery. This means that they continue to have facial weakness after several months. Some children have long-term mild facial weakness that is barely noticeable. A few children have more severe facial weakness that does not go away. 

If symptoms continue to worsen after 3 weeks or if there is no improvement by 4 months, the child’s doctor may run additional tests. 

RELATED DISORDERS

Other disorders with similar symptoms include: 

• Ramsay Hunt syndrome 
• Congenital facial nerve palsy 
• Traumatic facial nerve palsy 
• Melkersson-Rosenthal syndrome 
• Moebius syndrome 

Other disorders associated with the facial nerves include: 

• Congenital facial nerve palsy 
• Traumatic facial nerve palsy 
• Ramsay Hunt syndrome 

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Research 

ClinicalTrial.gov for Bell’s Palsy (birth to 17 years).

These are clinical trials that are recruiting or will be recruiting. Updates are made daily, so you are encouraged to check back frequently.  

ClinicalTrials.gov is a database of privately and publicly funded clinical studies conducted around the world. This is a resource provided by the U.S. National Library of Medicine (NLM), which is an institute within the National Institutes of Health (NIH). Listing a study does not mean it has been evaluated by the U.S. Federal Government. Please read the NLM disclaimer for details.   

Before participating in a study, you are encouraged to talk to your health care provider and learn about the risks and potential benefits.  

The information in the CNF Child Neurology Disorder Directory is not intended to provide diagnosis, treatment, or medical advice and should not be considered a substitute for advice from a healthcare professional. Content provided is for informational purposes only.  CNF is not responsible for actions taken based on the information included on this webpage. Please consult with a physician or other healthcare professional regarding any medical or health related diagnosis or treatment options. 

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