A commonly cited potential cause of Bell's palsy is:

A commonly cited potential cause of Bell's palsy is:

• A. Unknown cause, possibly viral
• B. Bacterial infection
• C. Autoimmune disease
• D. Vitamin deficiency

Answer: (A)

Bell's palsy is an acute facial nerve palsy where the exact cause is often not known. The most widely cited idea is that a latent viral infection—especially herpes simplex virus—reactivates and triggers inflammation of the facial nerve as it travels through its bony canal. That inflammatory process leads to swelling and compression of the nerve, causing sudden weakness of the facial muscles on one side. Because the cause is not clearly defined in many cases and a viral trigger is the leading hypothesis, choosing an unknown cause with a possible viral etiology is the best description. Bacterial infection, autoimmune disease, and vitamin deficiencies are not the primary explanations for Bell’s palsy, which is why they aren’t the best fit here.

Bell's palsy is an acute facial nerve palsy where the exact cause is often not known. The most widely cited idea is that a latent viral infection—especially herpes simplex virus—reactivates and triggers inflammation of the facial nerve as it travels through its bony canal. That inflammatory process leads to swelling and compression of the nerve, causing sudden weakness of the facial muscles on one side. Because the cause is not clearly defined in many cases and a viral trigger is the leading hypothesis, choosing an unknown cause with a possible viral etiology is the best description. Bacterial infection, autoimmune disease, and vitamin deficiencies are not the primary explanations for Bell’s palsy, which is why they aren’t the best fit here.