On Friday, Justin Bieber announced that he has Ramsay Hunt syndrome, a rare condition that has paralyzed half his face. Ramsay Hunt syndrome is a painful rash around the ear, on the face, or on the mouth and occurs when the varicella-zoster virus infects a nerve in the head.

Mount Sinai’s Joshua Rosenberg, MD, a nationally known expert on facial paralysis, is available to discuss Ramsay Hunt syndrome and symptoms/treatment/prognosis.