Facial paralysis (as seen in Bell's palsy) may develop days to months after a person is infected with Lyme disease. It's hard to be more precise than that. Most people with the typical rash of Lyme disease are treated. This prevents complications such as facial nerve palsy. For those without the rash, it can be impossible to date when the disease started.

Bell's palsy is a disorder of the facial nerve (also called the 7th cranial nerve). The muscles on one side of the face suddenly become paralyzed.

Symptoms may include:

• Drooping of the face
• An inability to raise the eyebrow
• Inability to shut the eye
• Facial numbness
• Drooling
• Inability to taste
• Heightened sensitivity to sound

Occasionally, facial nerve palsies affect both sides of the face.

When no cause for the condition is found, it is called Bell's palsy, named for Sir Charles Bell. This Scottish surgeon described details of facial nerve function in the 1800s. When a cause is found (such as when it's due to Lyme disease), the condition is called facial nerve palsy.

Lyme disease is a bacterial infection transmitted to humans by infected ticks. It's a relatively rare cause of facial nerve palsy. Only about 10% of people with Lyme disease develop facial nerve palsy. About 90% of have a rash, 60% have joint pain or arthritis, while just 10% have neurological problems, such as facial nerve palsy.

Antibiotics are generally quite effective for treating Lyme disease, including facial nerve palsy.