Bell’s palsy affects roughly 25 out of every 100,000 people per year in the United States, making it the most common cause of sudden facial paralysis. Your lifetime risk of experiencing it is about 1 in 60. While that makes it relatively uncommon on any given day, it adds up: most people know someone who has had it, and the condition appears to be getting more frequent over time.
Annual Incidence and Trends
Studies over the past several decades have placed the incidence of Bell’s palsy somewhere between 11 and 53 new cases per 100,000 people each year, depending on the country and time period. A large U.S. analysis of insurance claims data from 2007 to 2022 found an overall rate of 24.5 per 100,000 person-years, which is the most commonly cited current figure.
What’s notable is the upward trend. That same U.S. study found the incidence rose from 15.2 per 100,000 in 2007 to 35.3 per 100,000 in 2022, more than doubling over 15 years. Whether this reflects a true increase in cases or better detection and reporting isn’t entirely clear, but the pattern is consistent enough to draw attention from researchers.
Who Gets It Most Often
Bell’s palsy peaks between ages 15 and 40, which surprises many people who assume nerve conditions mostly affect older adults. Men and women develop it at roughly equal rates. A pooled analysis of multiple studies found a slight male predominance (51.5%), but the difference is small enough to be essentially even.
Pregnant women are a notable exception. The frequency of Bell’s palsy during pregnancy is about three times that of the general population, with the highest risk occurring in the third trimester and the first two weeks after delivery. This is thought to be related to fluid retention and swelling that can compress the facial nerve in the narrow bony canal it passes through.
Risk Factors That Increase Your Odds
The strongest known risk factor is herpes simplex virus, the same virus responsible for cold sores. A large real-world analysis of over 281,000 patients found that people with herpes simplex were about 6.5 times more likely to develop Bell’s palsy. The leading theory is that the virus lies dormant in the facial nerve and can reactivate, causing inflammation and swelling that disrupts nerve function. Many people carrying the virus never realize it, which means a significant number of Bell’s palsy cases may stem from viral reactivation that was never detected.
Diabetes is another well-established risk factor. In one clinical series of 126 Bell’s palsy patients, 39% had either overt or undiagnosed diabetes. The connection likely involves nerve damage from chronically elevated blood sugar, which makes the facial nerve more vulnerable to compression and inflammation. Depression and other immune-modulating conditions have also been flagged as associated risks, though the evidence is less robust.
Seasonal Patterns
Bell’s palsy is more common in cold weather. Multiple studies have found the highest incidence during winter months (December through February), with one finding that 35% of cases occurred in winter compared to just 20% in spring and 22% in summer. Cold, dry air and the respiratory infections that come with winter are the suspected drivers, though a large meta-analysis noted that while winter proportions are consistently the highest, the absolute seasonal difference is only about 5 percentage points. You can develop Bell’s palsy at any time of year.
Recurrence and Bilateral Cases
Most people who get Bell’s palsy experience it once and never again. Recurrence rates range from about 3% to 15% across different studies, with 7% being a commonly reported middle figure. When the condition does come back, it can affect the same side or the opposite side of the face.
Bilateral Bell’s palsy, where both sides of the face are paralyzed simultaneously, is genuinely rare. It accounts for about 2% of all facial nerve paralysis cases, affecting roughly 1 in 5 million people. When facial paralysis does show up on both sides at once, doctors typically investigate more aggressively because bilateral cases are more likely to have an identifiable underlying cause rather than being truly idiopathic.
Recovery Outlook
The 1 in 60 lifetime risk sounds alarming, but the prognosis is reassuring. The majority of people with Bell’s palsy recover fully, typically within three to six months. Younger patients and those with incomplete paralysis (some movement preserved from the start) tend to recover fastest and most completely. A smaller percentage, generally estimated at 15% to 20%, are left with some degree of residual weakness or involuntary facial movements. Severe cases with total paralysis at onset carry a higher risk of incomplete recovery, but even among these patients, many regain functional movement over time.