What is Ramsay Hunt syndrome, the virus attacking Justin Bieber's face?

Pop star Justin Bieber announced his face is partially paralyzed by a viral condition

called Ramsay Hunt syndrome, caused by the same virus, varicella-zoster, that causes chicken pox and shingles.

He told fans in a YouTube video Friday that the virus had attacked "the nerve in my ear, facial

nerves and has caused my face to have paralysis. You can see this eye is not blinking.

I can't smile on this side of my face. This nostril will not move."

Ramsay Hunt syndrome is a rare neurological disorder that occurs when the varicella-zoster virus infects a nerve in the head near the inner ear.

After having chickenpox as a child or shingles as an adult, the virus can lay dormant in the body.

Why the virus reactivates and produces symptoms of Ramsay Hunt is not known.

Ramsay Hunt syndrome can also cause hearing loss on the side of the face affected. Like Bieber,