You look in the mirror, and something’s different. One side of your face is drooping. The muscles seem weak. Is it a symptom of multiple sclerosis (MS), or something else?

Bell’s palsy causes weakness and drooping on one side of the face. It can be a rare symptom of MS, affecting about 0.2 percent of people with multiple sclerosis. Not being able to move part of your face can be quite shocking, and you may be confused about whether it’s a sign of an MS relapse or whether you should go to the hospital.

In this article, we’ll cover the signs of Bell’s palsy and its connection to MS.

What Is Bell’s Palsy?

Bell’s palsy is a neurological condition in which the muscles on one side of the face become weak or paralyzed. When facial muscles are paralyzed, it causes one side of your face to appear droopy or saggy. When you try to smile, your grin may be one-sided. Sometimes, Bell’s palsy can affect your eye, which may be difficult to close.

In Bell’s palsy, there is swelling, damage to, or inflammation of the facial nerve. The facial nerve is responsible for controlling many of the muscles in your face.

Bell’s palsy is usually an isolated episode related to a viral infection. There is no known cure, but fortunately, the facial paralysis is usually not permanent. Most people make a full recovery, which takes anywhere from three weeks to six months from the time the symptoms start. It’s rare for someone to experience more than one episode of Bell’s palsy or to have permanent damage.

Signs and Symptoms of Bell’s Palsy

Bell’s palsy is a condition that comes on suddenly, then gradually worsens for between 48 hours and 72 hours. Other symptoms can appear alongside facial weakness, including:

• Numbness in the face
• Headache
• Pain
• Abnormal muscle movements when smiling, blinking, eating, or drinking
• Inability to close the affected eye, risking damage to the cornea
• Tears in the affected eye
• Drooling on the affected side of the mouth
• Loss of taste
• Hypersensitivity to sound in the affected ear

With Bell’s palsy, these symptoms typically only appear on one side of the face. If you notice facial sagging, eye issues, muscle weakness, or pain on both sides of the face, it’s probably not Bell’s palsy, and you should notify your doctor.

Is It Bell’s Palsy, MS, or Something Else?

While one-sided facial weakness can be quite frightening when it first appears, it might not be Bell’s palsy. MS also causes muscle weakness, which can affect the eyelid and mouth. Facial nerve weakness can also develop due to a different health problem or occur after surgery.

Can MS Cause Bell’s Palsy?

One study found that among 2,260 participants who had MS, 3.27 percent had some type of facial palsy. In addition, 1.28 percent of those studied experienced eye muscle twitching, and 0.84 percent had spasms affecting one side of the face.

If you have new facial weakness, speak to your doctor right away. If facial weakness comes on suddenly — over the course of minutes to hours — that could be the sign of a stroke. If this happens, you should go to the nearest emergency room as soon as possible.

How Are Bell’s Palsy and MS Connected?

MS is an autoimmune disease in which the immune system attacks the central nervous system (CNS, which includes the brain and spinal cord). Bell’s palsy, on the other hand, is a disorder of the peripheral nervous system and originates in the facial nerve — outside of the brain and spinal cord. Researchers have published some case reports of people who experienced episodes of Bell’s palsy as a symptom of MS. This may occur when an MS lesion affects nerves controlling facial muscles.

Does MS Affect the Facial Nerve?

It’s rare for people with MS to have facial nerve paralysis as their only symptom. Some researchers have suggested that MS could cause some cases of Bell’s palsy, especially through lesions affecting the brainstem, but they do not believe that having Bell's palsy increases the risk for an MS diagnosis.

A study that looked at 107 people with MS found that facial muscle paralysis was the first MS symptom for about 5 percent of study participants. One case report described a woman who was first misdiagnosed with Bell’s palsy but was later found to have MS. Delayed MS diagnosis can have serious consequences, so more research is needed on whether demyelinating diseases such as MS could raise the risk for Bell’s palsy.

In summary, Bell’s palsy can be a symptom of MS, but it’s very rare.

“I’ve had Bell’s palsy in the past. It was on my left side of my face,” one MyMSTeam member wrote. “I think it was MS-related, but who knows?”

MyMSTeam Members’ Experience With Bell’s Palsy

Some members of MyMSTeam have described having Bell’s palsy. “I was diagnosed 35 years ago, and it started with Bell's palsy,” one member said. Another wrote about developing Bell’s palsy with seemingly stable MS: “I just got my MRI back, and I haven’t progressed in four years now. Then boom — Bell’s palsy a week later. It’s really irritating.”

Some members have visited the ER or been admitted to the hospital because of new symptoms of Bell’s palsy. “I recently went to the doctor for pain on the right side of my face. I thought I had an ear infection or a toothache, and I ended up having Bell’s palsy,” one shared.

Another member explained how Bell’s palsy impacted their day-to-day life: “Have had a bad relapse as well as Bell’s palsy, so it’s been really hard. The Bell’s palsy is starting to lift. I’ve had it five months now, as well as a relapse of MS, but never had one as bad as this. I have double vision, which makes things a bit more difficult than usual.”

Causes and Risk Factors

The cause of Bell’s palsy is unknown at this time. It’s thought that inflammation from the immune system may lead to swelling of the facial nerve, especially when you are recovering from a virus.

Viruses associated with the development of Bell’s palsy include:

• Epstein-Barr virus
• Herpes simplex virus (cold sores, genital herpes)
• Herpes zoster virus (chickenpox, shingles)
• Influenza B virus (the flu)
• Adenovirus
• Rubella (German measles)
• Cytomegalovirus
• Coxsackievirus (hand, foot, and mouth disease)

Certain people have a greater risk of Bell’s palsy. While Bell’s palsy can happen to anyone, it’s most often seen in people 15 to 45 years old. Pregnant people, especially those who are in the third trimester, are more likely to experience Bell’s palsy. The week after giving birth is also considered to be a higher-risk time period.

People whose immune systems are suppressed — through a medical condition, an autoimmune disease, stress, trauma, or medication — are at greater risk. Lyme disease, Guillain-Barre syndrome, sarcoidosis, and diabetes are all sometimes associated with Bell’s palsy.

Several known medical risk factors contribute to a higher likelihood of developing Bell’s palsy. These can include:

• High blood pressure
• Diabetes
• Upper respiratory tract infection (cold or flu)
• Infection of the facial nerve
• Certain toxins
• Higher body weight

Treating MS and Bell’s Palsy

If Bell’s palsy is caused by an infection or another health condition, treating the underlying health issue can help. Regardless of the cause, your health care provider can also help you manage symptoms.

Dry eye on the affected side of the face can be a real problem for people with Bell’s palsy. This can lead to a variety of serious symptoms, including blurry vision and eye ulcers. Proper eye care may consist of eye drops in the daytime, ointment right before going to sleep, or a moisture chamber in the evening.

Other Bell’s palsy therapies depend on how severe your symptoms are and any other medical problems you have. These may include:

• Corticosteroids, such as prednisone, to help with inflammation
• Antiviral medications
• Over-the-counter pain relief medications
• Moist, warm cloths applied to the face to soothe pain
• Physical therapy to help with facial nerve motor function

There is some interest in alternative treatments for Bell’s palsy, although there’s currently no scientific evidence that they can help. Some people try alternative therapies such as:

• Acupuncture
• Relaxation techniques
• Electrical stimulation
• B6, B12, and zinc supplements
• Biofeedback training

While Bell’s palsy can be scary, it’s important to remember that most people make a full recovery. Talk to your neurologist about any facial weakness or droopiness you notice before trying any alternative therapies.

Facial weakness can have many other causes besides Bell’s palsy, and some of them are serious. If you experience a sudden onset of drooping or weakness in one side of the face (within minutes to hours), go to the nearest emergency room without delay so doctors can check for a stroke.

Talk With Others Who Understand

MyMSTeam is the social network for people with MS and their loved ones. On MyMSTeam, more than 217,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Have you had Bell’s palsy or facial symptoms related to MS? Do you have any tips for managing facial weakness? Share your experience in the comments below, or start a conversation by posting on your Activities page.