Bell's Palsy: Symptoms, Causes & Treatment

Bell’s palsy is a condition caused by inflammation of the facial nerve, leading to sudden weakness or paralysis on one side of the face. Common symptoms include a crooked mouth, difficulty closing one eye, and trouble making facial expressions.

In most cases, Bell’s palsy is temporary and improves within a few weeks to months, although some people may have longer-lasting effects. It is often linked to viral infections such as herpes, mumps, or rubella, but the exact cause is not always clear.

Diagnosis is based on symptoms and exams to rule out serious conditions like stroke, while treatment may include corticosteroids, antivirals, physical therapy, or eye care. In some cases, therapies such as speech therapy, Botox injections, or surgery may be needed, and recovery typically occurs within a few months.

Bell’s palsy symptoms

The main symptoms of Bell’s palsy are:

• Partial or complete loss of movement on one side of the face

• A feeling of heaviness on the affected side of the face

• Difficulty closing the eye

• Crooked mouth

• Dry eyes and dry mouth

• Ear pain on the affected side

• Difficulty making facial expressions, eating, or drinking

• Mild pain or tingling on the affected side

• Drooling

Bell’s palsy symptoms appear quickly and suddenly, worsening over the course of a day or a week, with the most severe point usually occurring within 72 hours.

These symptoms usually affect only one side of the face. However, in rarer cases, the nerve can become inflamed on both sides of the face, causing symptoms on both sides.

Symptoms of Bell’s palsy can resemble those of more serious conditions, such as a stroke or brain tumor. According to the CDC, sudden weakness or numbness in the face, arm, or leg, especially on one side of the body, can be a warning sign of stroke and requires emergency medical care.

What's the difference between Bell’s palsy and a stroke?

Although they can cause similar symptoms, Bell’s palsy and stroke are different conditions.

Bell’s palsy happens due to inflammation of the facial nerve, which controls facial movements. This leads to loss of muscle control on one side of the face.

A stroke happens when the blood and oxygen supply to the brain is interrupted or reduced, usually due to a blockage or rupture of a blood vessel in the brain. This causes symptoms on one side of the body, not only the face.

Confirming a diagnosis

Bell’s palsy is diagnosed by a primary care provider or neurologist through an evaluation of symptoms, health history, a physical exam of the facial muscles, and a neurological exam.

The doctor may also order additional tests, such as an MRI, to rule out other conditions with similar symptoms, such as stroke, brain tumor, Lyme disease, or Ramsay Hunt syndrome.

Other tests, such as nerve conduction studies or electromyography, may be requested to assess the severity of facial nerve paralysis, especially in more severe or atypical cases.

What causes Bell's palsy?

The exact cause of Bell’s palsy is not fully understood. It occurs when the seventh cranial (facial) nerve becomes inflamed, which leads to the symptoms of the condition.

Bell’s palsy is usually linked to viral infections, such as:

• Herpes simplex or herpes zoster

• Infectious mononucleosis

• Mumps

• Rubella

• Epstein-Barr virus

• Coxsackievirus

• Cytomegalovirus

In addition, skull fractures or tumors can also lead to inflammation and compression of the facial nerve, resulting in Bell’s palsy.

Bell's palsy treatment

Treatment for Bell’s palsy should be guided by a neurologist or primary care provider and varies depending on the severity of symptoms.

The main treatments for Bell’s palsy are:

1. Medication

Bell’s palsy medication that may be prescribed by a healthcare provider includes:

• Corticosteroids, such as prednisone or prednisolone, taken by mouth for about 1 week

• Antivirals, such as acyclovir, famciclovir, or valacyclovir, in cases of herpes simplex or herpes zoster infections, which may or may not be combined with corticosteroids

• Pain relievers, such as acetaminophen or ibuprofen, to relieve pain

• Artificial tears, to lubricate the eyes and prevent corneal injury

According to the American Academy of Otolaryngology-Head and Neck Surgery Foundation, oral steroids should be prescribed within 72 hours of symptom onset for people 16 years and older with Bell’s palsy.

The provider may also recommend using an eye patch before going to sleep to help prevent worsening dry eye and corneal problems.

2. Physical therapy

Physical therapy for Bell’s palsy may be recommended by a healthcare provider and should be done under the guidance of a physical therapist.

Exercises can help strengthen the facial muscles and improve blood flow to the affected nerve. The physical therapist will usually show you how to do these exercises at home so you can keep practicing and help your symptoms improve more quickly.

3. Speech therapy

Speech therapy may be recommended for Bell’s palsy, as it helps restore facial movements and expressions. It can also help stimulate speech, chewing, and swallowing functions.

This type of therapy should be done with a speech-language pathologist. The therapist, together with the doctor, will decide how many sessions you need per week and how long treatment should last.

4. Botox injections

A Botox injection may be given to help relax the upper eyelid muscle, allowing the eye to close and helping prevent corneal injury.

In this case, the doctor injects Botox through the skin or under the conjunctiva into the muscle that lifts the upper eyelid when paralysis prevents the eye from closing.

5. Surgery

In some cases, doctors may recommend facial nerve decompression surgery. However, this option is controversial and is usually considered only when Bell’s palsy causes complete paralysis and does not improve with other treatments.

Recovery time

Full recovery from Bell’s palsy should happen within about 3 to 4 months. Some improvement may be noticed soon after physical therapy is started.

About 15% of people with this type of peripheral facial paralysis do not fully recover. In these cases, Botox or surgery may be needed months later.