A teenage girl was brought in by her parents because she was unable to move the left side of her face for the past 2 days. She had no history of trauma or recent ear infections and was otherwise well. On examination it was found that she had absent brow furrowing, weak eye closure, and dropping of the angle of her mouth (Figure 202-1). She had a normal complete blood count and serum glucose. She was diagnosed with Bell’s palsy and was provided eye lubricants and guidance on keeping her left eye moist. Her physician discussed the available evidence about treatment with steroids and the excellent prognosis without treatment in children. She (with her parents in agreement) chose not to take the steroids. She had a full recovery over the next several weeks.

Bell’s palsy is an idiopathic paralysis of the facial nerve resulting in loss of brow furrowing, weak eye closure, and dropped angle of mouth. Treatment is eye protection. Treatment with oral steroids is standard of care in adults, but controversial in children. Prognosis for full recovery is excellent.

Idiopathic facial paralysis.

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  In a population-based study, incidence was 18.8/100,000 children.¹

  
  
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  Incident rate increases by age and is higher is female children.¹

  
  
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  Seventy percent of cases of acute peripheral facial nerve palsy are idiopathic (Bell’s palsy); 30 percent have known etiologic factors such as trauma, diabetes mellitus, polyneuritis, tumors, or infections such as herpes zoster, leprosy (Figure 202-2), or Borrelia.²

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  Etiology of Bell’s palsy is currently unknown and under debate; the prevailing theory suggests a viral etiology from the herpesfamily.

  
  
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  The facial nerve becomes inflamed, resulting in nerve compression.

  
  
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  Compression of the facial nerve compromises muscles of facial expression, taste fibers to the anterior tongue, pain fibers, and secretory fibers to the salivary and lacrimal glands.

  
  
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  This is a lower motor neuron lesion; the upper and lower portions of the face are affected (Figure 202-1). In upper motor neuron lesions (e.g., cortical stroke), the upper third of the face is spared, while the lower 2/3 are affected as a result of the bilateral innervation of the orbicularis, frontalis, and corrugator muscles, which allows sparing of upper face movement.