Did the Mona Lisa Have Bell's Palsy?

Steroids may help with Bell's palsy

Mona Lisa
Photographer/Getty Images

Your expression depends on both the corners of your eyes and mouth. Any weakness at these points and facial asymmetry results. Ever wonder why the Mona Lisa's smile looks off? It's because there's weakness in her smile. In fact, some experts have postulated that whoever Leonardo da Vinci was painting (his mother?) may have had Bell's palsy. (It's impossible to tell which side the Bell's palsy may have affected because we would need to have her grimace on physical exam.) 

Bell's palsy is the most common form of facial paralysis. During the course of a lifetime, this condition occurs in about 1 of 60 people. This disease is caused by inflammation of the facial nerve which innervates the muscles of facial expression, taste receptors in the tongue, and can result in one-sided (unilateral) facial weakness, facial contracture or stiffening, oversensitivity to sounds (hyperacusis), and loss of taste on one side of the tongue.

Risk Factors

The facial-nerve inflammation present in Bell's palsy resembles that which occurs during infection or immune diseases like herpes simplex virus (HSV) type 1. In fact, reactivation of HSV is commonly implicated as a potential cause of Bell's palsy. Other potential risk factors include diabetes, pregnancy and the influenza vaccine.

Weakness with Bell's palsy is usually worst at first onset. Onset of weakness is abrupt and is preceded by ear pain that lasts a day or two.

About 80 percent of all people affected with Bell's palsy fully recover.

Incomplete one-sided weakness is a good prognostic sign while more complete paralysis occurs with axonal (nerve) degeneration or death. With axonal degeneration, it may take a person three or more months to get better, and resolution may be incomplete with some degree of persistent facial weakness.

  In a minority of people, such persistent weakness is lifelong and accompanies other lifelong sequelae like hyperacusis, loss of taste, crocodile tears (inappropriate tearing), loss of tearing, loss of taste, and synkinesis (rewiring of facial innervation).   

When predicting whether Bell's palsy will resolve or persist in some iteration, clinicians consider the following characteristics:

  • Younger people with Bell's palsy are more likely to recover than older people. Of note, Bell's palsy typically affects people who are aged 15 to 45.
  • Early recovery is better than late recovery.
  • People without accompanying pain do better than people with pain.
  • All people with Bell's palsy recover to some degree with only 5 percent of people experiencing severe life-long symptoms or sequelae.
  • Presence of dry eye, taste loss or hearing problems bodes for a worse prognosis.
  • No difference in prognosis exists between the sexes,
  • Most people with Bell's palsy who experience full recover do so in three months. If you haven't gotten better by six months, however, the chance of full recovery is slim.
  • Prognosis is the same for left-sided and right-sided Bell's palsy.
  • Bell's palsy recurs in only 7 percent of people.


Decades ago, physicians used to treat Bell's palsy with apparatuses that emitted electricity or surgery.

Nowadays, treatment for Bell's palsy is more palliative and can include closing the affected eye with Scotch tape or an eye patch during sleep to prevent corneal drying or the use of Visine or some other type of eye drops. Facial massage may also help speed recovery with Bell's palsy.

Many physicians choose to treat Bell's palsy with a tapering dose of corticosteroids and antiviral agents like acyclovir. For some time, this practice was contentious. However, results from a randomized-control published in a 2007 issue of The New England Journal of Medicine suggest that early treatment with steroids (prednisolone) significantly improves the chance of recovery at three and nine months; whereas, treatment with acyclovir doesn't help when given either alone or with steroids.

Of note, Japanese researchers showed that valacyclovir (an antiviral pro-drug) combined with steroids resulted in greater recovery than either no treatment or treatment with steroids alone. Although it's unlikely that antivirals do much to help with Bell's palsy, because of their relative safety, many clinicians still prescribe them early in the course of treatment.

If you or someone you love is experiencing Bell's palsy, keep in mind that in most people, time heals all wounds. In other words, most people recover on their own without any specific treatments. However, steroids given shortly after onset may result in a greater chance of recovery.


Beal M, Hauser SL. Trigeminal Neuralgia, Bell’s Palsy, and Other Cranial Nerve Disorders. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 19e. New York, NY: McGraw-Hill; 2015. 

Gilden, DH and Tyler, KL. "Bell's Palsy—Is Glucocorticoid Treatment Enough." NEJM in 2002. 

Petersen, E. "Bell's Palsy: The Spontaneous Course of 2,500 Peripheral Facial Nerve Palsies of Different Etiologies." Acta Oto-laryngologica in 2002. 

Sullivan, FM. "Early Treatment with Prednisolone or Acyclovir in Bell's Palsy." NEJM in 2007. 

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