What is Ramsay Hunt syndrome, the condition that paralyzed half of Justin Bieber's face

• Justin Bieber has canceled upcoming tour dates because of a health condition called Ramsay Hunt syndrome.
• He previously suffered from temporary paralysis of part of his face related to the illness.

Pop star Justin Bieber has cancelled upcoming tour dates, according to Ticketmaster, as a result of ongoing health issues from a rare condition. Known as Ramsay Hunt syndrome, the illness previously left part of his face temporarily paralyzed.

The rare medical condition, caused by the same virus that causes chickenpox, is part of a series of medical issues Bieber has disclosed, including Lyme disease, Epstein Barr, and chronic anxiety.

The singer initially shared his diagnosis on Instagram in June 2022, telling followers he couldn't blink his eye or flare his nostril on the right side of his face. The symptoms also prompted him to cancel tour dates that summer in order to prioritize his health.

Facial paralysis is a characteristic symptom of Ramsay Hunt syndrome, which occurs when a virus called varicella zoster infects the facial nerve, according to the Mayo Clinic. The virus is typically associated with chickenpox, but also causes shingles — a reactivation of the virus after a person recovers from chickenpox — which leads to a painful, itchy, rash, according to the CDC.

Children are now routinely vaccinated for the chickenpox, which reduces the chances of becoming infected. The vaccine became available in the U.S. in 1995, and approved for use in Canada, where Bieber was born, in 1998.

Ramsay Hunt syndrome can also cause hearing loss, ringing in the ears, painful blisters near the ear. It affects an estimated 5 out of every 100,000 people in the United States per year, according to the Rare Disease Database.

In some cases, the paralysis can be permanent, although symptoms usually resolve after treatment with medications like antiviral drugs and corticosteroids, according to the Mayo Clinic.