What neurological condition causes facial paralysis?

• A. Bell's palsy
• B. Otitis media
• C. Cluster headache
• D. Trigeminal neuritis

Answer: (A)

Facial paralysis comes from a problem with the facial nerve (cranial nerve VII), which controls the muscles of facial expression. Bell's palsy is the classic idiopathic peripheral facial nerve palsy, characterized by sudden or rapidly developing weakness on one side of the face, making it hard to close the eye, smile, or raise the eyebrow. Because the lesion affects the nerve after it exits the brain, both the upper and lower facial muscles on that side are weak, unlike central problems where the forehead may be spared due to bilateral innervation. Other listed conditions don’t typically present as primary facial paralysis: an otitis-related facial nerve involvement can occur but is not the usual cause of sudden facial weakness; cluster headache presents with severe unilateral head pain and autonomic features rather than muscle weakness; trigeminal neuritis affects facial sensation and muscles for chewing, not the facial expression muscles.