Hemifacial spasm is a nervous system condition that causes muscles on one side of the face to twitch or spasm. You cannot control hemifacial spasms. They usually start around one eye and may spread on that side of the face. The most common cause is a blood vessel pressing on the facial nerve. Sometimes there is no known cause. While hemifacial spasms are not life-threatening, they can be uncomfortable and affect social interaction.
Hemifacial spasms also are called muscle movements or contractions. These spasms often start in one eyelid. They might move to the cheek and mouth on the same side of the face. First, hemifacial spasms come and go. But over months to years, they occur almost all the time. How quickly they spread and how often they happen may be different for everyone.
Common symptoms of hemifacial spasm are usually painless but may include muscle movements:
Sometimes, hemifacial spasms occur on both sides of the face. However, they don't often occur on both sides of the face at the same time.
Certain things can increase hemifacial spasm symptoms, such as:
The most common cause of hemifacial spasms is a blood vessel touching a facial nerve. A tumor pressing against a facial nerve or a facial nerve injury also may cause them. Sometimes the cause isn't known.
Hemifacial spasm care at Mayo Clinic
Some studies show that these factors may increase the risk of hemifacial spasm:
There is no known way to prevent hemifacial spasm. But managing stress, fatigue and anxiety may help lessen symptoms.