Viral Infection and Immune Response Behind the Surge in Facial Paralysis Cases Worldwide
Nikhil Prasad Fact checked by:Thailand Medical News Team May 19, 2025 17 hours, 26 minutes ago
Medical News: Rising Cases of Facial Palsy Linked to Hidden Viral Triggers
In a groundbreaking new medical review, researchers from the Quzhou Hospital of Traditional Chinese Medicine in China have uncovered in great detail how various viral infections—especially herpes viruses and even SARS-CoV-2—can trigger facial paralysis through complex interactions with the body’s immune system. Their study offers new hope for better diagnostic and treatment strategies that could help millions affected by this debilitating condition.
Viral Infection and Immune Response Behind the Surge in Facial Paralysis Cases Worldwide
Facial palsy, commonly known as facial paralysis, affects the muscles responsible for expressions such as smiling, blinking, and frowning. It often comes on suddenly and usually affects only one side of the face. Bell’s palsy is the most well-known form, accounting for 60 to 75 percent of all facial palsy cases.
What many may not realize is that viral infections are now believed to be one of the main culprits behind this disorder. According to this
Medical News report, facial palsy can be triggered when certain viruses invade the body, lie dormant for years, and suddenly reactivate, unleashing inflammation and nerve damage that leads to partial or complete facial paralysis.
Viruses That Hide Then Strike
The researchers examined a host of viruses including herpes simplex virus type 1 (HSV-1), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), HIV, and SARS-CoV-2. These viruses have the dangerous ability to infect nerve tissues and remain hidden for long periods, only to reactivate later when the immune system is weakened.
For instance, HSV-1, the virus known for causing cold sores, travels through sensory nerves and hides in nerve ganglia. When reactivated, it can travel backwards along nerve fibers, inflaming and compressing the facial nerve, causing the classic signs of facial palsy such as drooping of the mouth or an inability to close one eye.
Varicella-zoster virus—the same virus responsible for chickenpox and shingles—is particularly notorious. After the initial infection, it remains dormant in the cranial nerves. When it flares up again, it can cause Ramsay Hunt Syndrome, a severe form of facial palsy that may come with hearing loss and severe pain.
SARS-CoV-2, the virus responsible for COVID-19, is also now being implicated. Researchers found that the virus might cause facial nerve damage through widespread inflammation, abnormal blood clotting, and direct invasion of nerve tissues, although the exact mechanisms are still being studied.
Immune System Gone Rogue
What makes these infections particularly devastating is not just the virus itself—but the body’s own immune system response to it. When these viruses attack, immune cells like T-cells, B-cells, macrophages, and natural killer cells rush to the site to destroy infected cells. This reaction
is meant to protect the body, but when it becomes too intense or misdirected, it can backfire.
Inflammatory chemicals called cytokines flood the area, causing swelling and pressure on the delicate facial nerves. In some cases, the immune system gets confused and starts attacking healthy nerve cells, mistaking them for virus-infected tissue. This autoimmune reaction can lead to nerve demyelination—a loss of the protective covering around nerves—and permanent damage.
The researchers warn that people with weakened immune systems, such as those with HIV or undergoing cancer treatments, are especially at risk for recurrent or severe facial palsy due to their inability to regulate viral infections and immune overactivation effectively.
Different Viruses Different Mechanisms
The study breaks down how each virus affects the nervous system differently:
-HSV-1 causes retrograde nerve inflammation, leading to swelling and facial nerve compression.
-VZV reactivates after years of dormancy, leading to inflammation, vesicular rash, and possible permanent facial nerve injury.
-SARS-CoV-2 disrupts the blood supply to the nerves and causes systemic inflammation that may impair nerve function.
-HIV weakens the immune system, making the nerves vulnerable to opportunistic infections.
-EBV causes immune-mediated nerve damage by stimulating excessive cytokine release.
Why the Immune Response Matters
One of the key findings is that timing matters. A properly regulated immune response in the early stages of viral infection can help neutralize the virus and reduce nerve inflammation. However, if the immune response is delayed, excessive, or misdirected, it can cause more harm than good.
Interestingly, memory immune cells—designed to “remember” past infections—may also contribute to repeat episodes of facial palsy. Upon reinfection, they rapidly produce inflammatory substances that can unintentionally harm nerve tissues.
Another concerning factor is the phenomenon known as “cytokine storm”—an overwhelming immune response that can damage multiple organs, including the brain and nerves. This was seen in some severe COVID-19 cases, where patients developed neurological complications like facial paralysis.
What This Means for the Future
The research emphasizes that diagnosing facial palsy should go beyond simply looking at symptoms. Doctors should also investigate whether a viral infection or immune disorder might be at play. This could involve checking for viral markers in the blood or testing for overactive immune responses.
Furthermore, personalized treatments that target both the virus and the immune system might offer better results than conventional therapies. For example, corticosteroids, which are already used to reduce inflammation, may be most effective when administered early. In the future, immune-modulating drugs, antiviral therapies, and even gene-based treatments could be used to both stop the virus and regulate the immune response more precisely.
A Call for More Research and Innovation
The researchers from Quzhou Hospital of Traditional Chinese Medicine—Aijun Wang, Wei Xie, and Jian Zhang—call for more in-depth studies into how different viruses trigger immune responses and how these interactions result in facial nerve damage. They also highlight the importance of integrating genetics, immunology, and advanced imaging technologies to identify new treatment targets.
In conclusion, this new understanding of the combined role of viruses and immune responses in facial palsy paves the way for better prevention, earlier diagnosis, and more effective treatments. It shows that facial palsy is not always “idiopathic” or without cause—in many cases, it is the result of a silent viral invasion and a misguided immune attack. With continued research, there is hope that this once mysterious condition can be tamed and even prevented.
The study findings were published in the peer reviewed Journal of NeuroVirology
https://link.springer.com/article/10.1007/s13365-025-01258-7
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Medical News.
Read Also:
https://www.thailandmedical.news/news/covid-19-infection-triggers-eye-nerve-damage
https://www.thailandmedical.news/news/covid-19-news-insights-from-a-polish-case-report-shows-that-sars-cov-2-infections-can-cause-femoral-nerve-palsy-due-to-coagulopathy-issues
https://www.thailandmedical.news/news/covid-19-symptoms-new-documented-case-shows-that-sars-cov-2-can-cause-cranial-nerve-palsy-with-resulting-double-eye-vision-diplopia
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/pages/thailand_doctors_listings
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