Bell's Palsy: Symptoms, Causes, and Treatment

Bell's palsy is sudden weakness or paralysis of facial muscles, usually on one side. While alarming, most cases are temporary with partial or full recovery typically within weeks to months. Early treatment with corticosteroids can improve recovery. The main priority is protecting your eye during recovery if you can't blink properly.

In plain words

Bell's palsy is sudden weakness or paralysis on one side of the face. It happens when the facial nerve gets inflamed or swollen. While it looks scary, most people get better in weeks to months. Early treatment with steroid medicines can help. The first signs are often a drooping mouth, trouble closing one eye, or pain behind the ear. Doctors need to check right away to rule out stroke. Protecting the eye that can't close fully is very important during recovery.

What is Bell's Palsy: Symptoms, Causes, and Treatment?

Bell's palsy is sudden weakness or paralysis of facial muscles, usually on one side. While alarming, most cases are temporary with partial or full recovery typically within weeks to months. Early treatment with corticosteroids can improve recovery. The main priority is protecting your eye during recovery if you can't blink properly.

Symptoms

Early symptoms

  • Facial drooping: Sudden weakness or paralysis typically on one side of the face, making it difficult to smile symmetrically or control facial expressions. (1) (4)
  • Difficulty closing one eye: Inability to fully close the eyelid on the affected side, which may lead to dryness or irritation if not managed. (1) (4)
  • Drooling from one side: Saliva may escape from the corner of the mouth on the weak side due to reduced muscle control. (4)
  • Impaired taste: Reduced or altered sense of taste on the front two-thirds of the tongue (the area controlled by the facial nerve). (4)
  • Increased sound sensitivity: Sounds may seem louder on the affected side (hyperacusis) due to nerve involvement near the ear. (1)
  • Jaw or ear pain: Some people experience discomfort around the jaw or behind the ear before facial weakness develops. (1)

Serious or emergency symptoms

  • Signs of stroke: If facial drooping is accompanied by severe headache, confusion, dizziness, weakness in limbs, or difficulty speaking, seek emergency care immediately to rule out stroke. Call emergency services immediately if stroke symptoms appear with facial paralysis. (5)
  • Eye complications: Pain, redness, or vision changes in the affected eye suggest potential corneal damage and require urgent medical attention. Seek same-day medical care if you develop eye pain or vision changes. (4)

Causes

Primary causes

  • Facial nerve inflammation: Swelling and compression of the facial nerve (cranial nerve VII) is believed to cause Bell's palsy, though the exact trigger isn't always identified. (2)
  • Viral infections: Herpes simplex virus (HSV-1) is most commonly implicated. Other possible viruses include herpes zoster (shingles), Epstein-Barr, and cytomegalovirus. (2)
  • No proven link to cold exposure: Contrary to common belief, drafts or cold weather don't cause Bell's palsy despite the older 'cold palsy' terminology. (2)

Risk factors

Diabetes

People with diabetes are 3-4 times more likely to develop Bell's palsy, possibly due to nerve susceptibility. (3)

Pregnancy

Higher risk, especially during the third trimester or first week postpartum, likely due to fluid retention and immune changes. (3)

Recent viral illness

Upper respiratory infections precede some cases of Bell's palsy by 1-2 weeks. (3)

Diagnosis

Doctors diagnose Bell's palsy mainly through physical examination after ruling out other causes like stroke. There's no specific test. Your doctor will check for characteristic facial weakness patterns and may ask you to perform movements like smiling, frowning, and closing your eyes tightly. If symptoms are atypical, further tests like blood work or imaging might be needed to exclude other conditions.

Physical examination

Assesses characteristic patterns of facial weakness and rules out other neurological conditions. (1) (3)

Blood tests

May check for diabetes, infections like Lyme disease, or other underlying conditions if symptoms are atypical. (5)

Electromyography (EMG)

Measures nerve activity in severe or prolonged cases to assess damage extent and recovery potential. (5)

Treatment

Medication options

Corticosteroids

Reduce nerve inflammation and swelling, improving recovery chances if started within 72 hours of symptom onset. (6) (7)

Antiviral medications

May be considered if herpes infection is suspected, though evidence for benefit is mixed and they are often used with steroids if at all. (6) (7)

Lifestyle and self-care

  • Eye protection: Use artificial tears during the day and lubricating ointment at night if eyelid closure is impaired. Wear sunglasses outdoors. Special moisture chambers may be recommended for sleep. (4) (6)
  • Gentle facial exercises: Once improvement begins, simple exercises like smiling, puffing cheeks, and raising eyebrows may help maintain muscle tone and coordination. (8)
  • Diet modification: Chew carefully on the unaffected side to prevent accidental biting. Use a straw for liquids if drinking is difficult. (8)

Always discuss dosing and treatment changes with your own prescriber.

Possible complications

  • Incomplete recovery: About 15% of people have lasting weakness, muscle tightness, or involuntary facial movements (synkinesis) after recovery. (4) (7)
  • Eye damage: Corneal abrasions or ulcers can occur if the eye isn't protected from dryness when blink reflex is impaired. (4)
  • Crocodile tears syndrome: Rare complication where tears occur while eating due to abnormal nerve regeneration. (7)

When to see a doctor

Routine follow-up

  • Schedule a visit if you notice gradual or partial facial weakness developing over days to weeks. (5)
  • Follow up if symptoms don't begin improving within 3-4 weeks or if you develop new symptoms during recovery. (5)

Seek emergency care

  • Seek immediate care for sudden facial paralysis to rule out stroke, especially if accompanied by headache, confusion, or weakness elsewhere. (5)
  • Get urgent eye evaluation if you experience eye pain, redness, or vision changes due to inability to blink properly. (4)

Frequently asked questions

What are the first signs of Bell's palsy?

The earliest symptoms are often facial twitching, slight drooping that worsens over 1-2 days, difficulty keeping liquid in your mouth while drinking, or inability to fully close one eye. Many notice these changes upon waking. Some experience pain behind the ear before weakness appears. (1) (4)

Is Bell's palsy contagious?

No, the facial paralysis itself isn't contagious. If caused by an active viral infection (like herpes), that particular virus might be transmissible through its usual routes, but you can't 'catch' Bell's palsy from someone who has it. (2)

How long does Bell's palsy last?

Most people (about 70%) recover completely within weeks to months, with improvement often starting within 3 weeks. Complete recovery may take up to 6 months. About 15% experience lasting mild weakness, and a small percentage have significant permanent effects. (1) (4)

Can Bell's palsy be cured?

Most cases resolve completely without treatment, though corticosteroids improve recovery chances when started early. Complete recovery occurs in about 85% of people. Those with incomplete recovery may benefit from physical therapy or, rarely, surgical options to improve facial function. (6) (4)

Does Bell's palsy always affect just one side?

Over 99% of Bell's palsy cases affect one side only. Bilateral facial paralysis is extremely rare and suggests a different condition that requires thorough medical evaluation. (4)

References

  1. NHS — Bell's palsy source 1
  2. MedlinePlus — Bell's Palsy source 2
  3. CDC — Bell's Palsy Clinical Overview source 3
  4. Cleveland Clinic — Bell's Palsy source 4
  5. NHS — Bell's palsy Diagnosis source 5
  6. NHS — Bell's palsy Treatment source 6
  7. MedlinePlus — Bell's Palsy Treatment source 7
  8. Cleveland Clinic — Living With Bell's Palsy source 8