The exact cause of Bell’s palsy is unknown but it’s often associated with a viral infection. The nerve that controls facial muscles passes through a narrow bone channel in the skull before reaching the face. A viral infection can cause the nerve to become inflamed or swollen. In addition to face muscles, the facial nerve affects tears, saliva, taste and hearing. With some recurring cases, there’s a family history of recurring Bell’s palsy, which suggests a genetic link or cause.
These viruses have been linked to having Bell’s palsy:
Who’s at risk of developing Bell’s palsy?
People at higher risk of having Bell’s palsy include those with: