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

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.

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.

Symptoms can include a painful rash inside the ear canal and outside the ear, at times attacking the tongue and roof of the mouth, according to the Icahn School of Medicine at Mount Sinai. 

That weakness can cause difficulty with closing one eye, making facial expressions and eating, as food can fall out of the side of the weakened mouth.

Treatment consists of steroids such as prednisone to reduce inflammation and pain medication.

Bierber assured fans that he is “gonna get better” and that he was doing “facial exercises to get my face back to normal.”

“It will go back to normal – it’s just time and we don’t know how much time, but it’s going to be OK,” he said in the video.