When half your smile suddenly disappears

George Clooney once revealed that he developed Bell’s palsy as a teenager after waking up unable to move one side of his face. Years later, Angelina Jolie shared that she experienced the same condition following an especially stressful period in her life.

Despite affecting well-known personalities, Bell’s palsy remains widely misunderstood. The condition is the leading cause of sudden weakness or paralysis on one side of the face, occurring when the facial nerve becomes inflamed and interrupts signals between the brain and facial muscles.

“It often develops unexpectedly,” neurologist Dr. Donnabelle M. Chu explained. “A person may wake up unable to smile evenly or completely close one eye.”

The facial nerve, also known as the seventh cranial nerve, controls facial movement, contributes to taste sensation, and helps regulate tear and saliva production. When inflammation affects this nerve, everyday actions such as smiling, blinking, or raising an eyebrow can suddenly become difficult.

Symptoms usually appear within 48 to 72 hours and may include facial drooping, difficulty closing one eye, headaches, altered sense of taste, increased sensitivity to sound, and either excessive tearing or dry eyes on the affected side.

Although doctors have yet to identify a single cause, Bell’s palsy is believed to be linked to dormant viral infections that become active under certain conditions. Stress, insufficient sleep, and a weakened immune system are also considered possible contributing factors.

Certain groups are at greater risk of developing the condition, including pregnant women — particularly during the third trimester or shortly after childbirth — as well as people living with diabetes, high blood pressure, obesity, or a family history of Bell’s palsy.

Because Bell’s palsy shares one noticeable symptom with stroke — facial drooping — it is often confused with the medical emergency. However, experts stress that a stroke usually affects more than just the face and may also cause weakness in an arm or leg, slurred speech, or vision problems.

“Medical evaluation is essential because the symptoms can overlap,” Dr. Chu said. “It’s important to determine whether a person is experiencing Bell’s palsy or something more serious, such as a stroke.”

Doctors may perform a physical examination and, when necessary, request imaging scans or nerve tests to rule out other neurological conditions.