Context

Bell’s palsy is an idiopathic unilateral lower motor neurone facial nerve paralysis of acute onset [1] which includes:

• Inability to wrinkle the forehead on the affected side
• Inability to close the affected eye
• Flattening of the nasolabial fold on the affected side

The incidence of Bell’s palsy is:

• 20-25/100 000 per year in adults [2,3]
• 13-30/100 000 per year in all age groups [4]
• 1.6/100 000 per year in children [4]

There are no geographic, gender or race differences [2].

The incidence in children is lower than in adults and needs careful assessment to look for potentially serious causes [3].

Learning bite

Lower motor neurone paralysis of the facial nerve affects the entire face. Upper motor neurone weakness only affects the lower half of the face [1].