The office of Sen. Dianne Feinstein, the 89-year-old California Democrat who was diagnosed with shingles in February, confirmed Thursday she “continues to have complications” from a viral infection called Ramsay Hunt syndrome. The syndrome is caused by the same virus, varicella-zoster, that causes chickenpox and shingles. In June, 2022, pop star Justin Bieber announced his face was partially paralyzed by the same virus. He told fans in a YouTube video 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. He told his fans that same month that — after doing facial exercises to battle the paralysis — he was slowly recovering, saying, “Each day has gotten better.” And in March of this year, he shared a video of his face with a caption “Wait for it,” then flashed a huge smile. The syndrome, which is not contagious, affects about 5 out of every 100,000 people yearly in the United States, although some medical professionals believe many cases are undiagnosed. “This makes its true frequency more difficult to determine,” the Cleveland Clinic noted. 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. Due to the inner ear involvement, people with the condition can also suffer vertigo (the sensation of dizziness or things spinning around you), or tinnitus, a ringing in the ear. Ramsay Hunt syndrome can also cause hearing loss on the side of the face affected. As in Bieber’s case, it can also cause a weakness, facial droop or paralysis on the side of the face affected by the virus. 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. At times, antiviral medicines that help with the herpes family, such as acyclovir or valacyclovir may be prescribed. About 70% of people with Ramsay Hunt will regain complete or “almost complete” function of facial muscles, according to the Cleveland Clinic. Recovery time depends on the severity of the paralysis, and can take up to a year. “Chances of a full recovery are better if you start treatment within three days of symptoms appearing. Early diagnosis and prompt treatment with antiviral therapy seem to improve long-term outcomes,” the Cleveland Clinic notes on its website.