COVID-19 can damage nerves through several distinct routes, from direct viral invasion of nerve cells to runaway immune responses that attack nerve fibers long after the initial infection clears. Neurological complications range from temporary loss of smell to lasting pain syndromes and conditions like Guillain-Barré syndrome. A systematic review comparing COVID-19 to other viral infections found that SARS-CoV-2 stands out for both the breadth and severity of its neurological effects, as well as the persistence of symptoms in many survivors. The picture is more layered than a single mechanism or a single type of nerve injury, which is part of why so many patients and clinicians find it confusing.
How SARS-CoV-2 Gets Into Nerve Cells
One of the first questions researchers needed to answer was whether the virus could infect neurons at all, or whether nerve symptoms were purely collateral damage from inflammation. The answer turned out to be both. The virus can directly enter certain nerve cells, and it also triggers immune reactions that harm nerves independently.
The main entry point for SARS-CoV-2 into most cells is the ACE2 receptor. Researchers found that sensory neurons in the dorsal root ganglia, the clusters of nerve cell bodies that relay pain and touch signals from your body to your spinal cord, express ACE2 at both the genetic and protein level. A specific subset of pain-sensing neurons that form free nerve endings in the outermost layers of skin and the lining of hollow organs appear particularly vulnerable, because they co-express the receptor along with markers identifying them as nociceptors, the neurons responsible for detecting painful stimuli.1PubMed Central. ACE2 and SCARF expression in human dorsal root ganglion nociceptors: implications for SARS-CoV-2 virus neurological effects
Animal studies confirmed that the virus does not just dock on these receptors passively. Experiments in mice and hamsters showed viral RNA, viral proteins, and infectious virus in peripheral sensory and autonomic neurons, as well as in satellite glial cells (the support cells surrounding neurons) and connected central nervous system tissues. The virus also uses a second molecular doorway called neuropilin-1 to facilitate entry into neurons.2PubMed Central. SARS-CoV-2 Rapidly Infects Peripheral Sensory and Autonomic Neurons, Contributing to Central Nervous System Neuroinvasion before Viremia This means the virus can potentially reach the central nervous system by traveling along peripheral nerves before it even reaches high levels in the bloodstream, a route that helps explain why neurological symptoms sometimes appear very early in infection.
The Immune System Turns on Nerves
Direct viral invasion is only part of the story. In many patients, the immune response itself does more lasting damage to nerves than the virus. COVID-19 triggers a surge of inflammatory signaling molecules, and several of these same molecules are well-established drivers of nerve pain and nerve injury. TNF-alpha, IL-1-beta, and IL-6 are elevated during both the acute infection and the post-COVID phase, and all three overlap with the inflammatory mediators known to promote neuropathic pain.3Frontiers in Neurology. Guillain–Barre syndrome and link with COVID-19 infection and vaccination: a review of literature
This inflammatory cascade can strip the protective myelin coating from nerve fibers, damage the small blood vessels that feed nerves, or trigger autoimmune attacks where the body’s own antibodies target nerve components. Micro-thrombotic events, tiny blood clots forming in the vessels supplying nerves, have also been identified as a mechanism behind some peripheral nerve complications during COVID-19.4Journal of the Neurological Sciences. Peripheral neurological complications during COVID-19: A single center experience
Guillain-Barré Syndrome and Acute Nerve Emergencies
Guillain-Barré syndrome, or GBS, is an acute condition where the immune system attacks peripheral nerves, causing rapidly progressing weakness that can become life-threatening if it reaches the muscles controlling breathing. It has been reported in association with several infections over the decades, and COVID-19 joined that list early in the pandemic.
A systematic review found that the inflammatory cascade triggered by SARS-CoV-2 actively contributes to the kind of immune dysregulation that can precipitate GBS.5PubMed Central. Guillain–Barré syndrome associated with COVID-19: A systematic review Based on electrophysiological data, COVID-associated GBS tends to present as an acute inflammatory demyelinating polyneuropathy, meaning the immune attack targets the myelin sheath rather than the nerve fiber itself.6PubMed Central. Is there a causal nexus between COVID-19 infection, COVID-19 vaccination, and Guillain-Barré syndrome? The good news is that GBS remains uncommon even among COVID-19 patients, but it is serious enough that sudden onset of limb weakness after a recent infection warrants urgent medical evaluation.
Small Fiber Neuropathy and Persistent Pain
While GBS grabs headlines because of its severity, the far more common nerve problem after COVID-19 involves small fiber neuropathy, or SFN. Small fibers are the thinnest nerve endings in your skin and organs, responsible for sensing pain, temperature, and light touch, as well as controlling involuntary functions like sweating and blood vessel tone. When these fibers are damaged, the result is a distinctive and often miserable set of symptoms.
People with post-COVID small fiber neuropathy describe burning pain, pins-and-needles sensations, painful cold feelings, electric shock-like jolts, itchiness, numbness, and heightened skin sensitivity called allodynia, where even light contact feels painful. These symptoms can appear in the limbs, trunk, and neck. Less commonly reported but still documented are burning sensations in the eyes or mouth.7PubMed Central. A clinical approach to the investigation and management of long COVID associated neuropathic pain
Skin biopsy studies of patients with persistent neuropathic skin pain after COVID-19 have revealed abnormal nerve fiber changes at the tissue level. One investigation found hypertrophy of small nerve endings, a condition described as “dermal hyperneury,” along with disturbances in the specific nerve fiber types responsible for pain and temperature sensation. These structural changes help explain why patients experience dysesthesia, unpleasant abnormal sensations triggered by ordinary stimuli.8PubMed Central. The Pathological Culprit of Neuropathic Skin Pain in Long COVID-19 Patients: A Case Series
A case-control study of 16 patients diagnosed with SFN by skin biopsy after COVID-19 found a striking overlap with chronic fatigue: 92% reported the kind of post-exertional malaise characteristic of myalgic encephalomyelitis/chronic fatigue syndrome, and testing demonstrated neurovascular dysregulation and autonomic dysfunction. Nine of these patients were treated with intravenous immunoglobulin, or IVIG, and all nine showed clinical improvement in their neuropathic symptoms, with six experiencing complete resolution.9PubMed Central. Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19 That response rate, though from a small group, suggests an immune-mediated mechanism that can be interrupted with the right treatment, which is encouraging for patients stuck in prolonged pain.
Diagnosing Small Fiber Damage
One frustration patients often encounter is that standard nerve conduction studies, the electrical tests a neurologist typically orders, come back normal. That is because those tests only measure large-diameter nerve fibers. Small fiber neuropathy, by definition, involves fibers too small to show up on routine testing. Patients are sometimes told there is nothing wrong with their nerves when the real issue is that the wrong test was used.
Proper evaluation for suspected post-COVID SFN requires specialized tools. A cohort study of long-COVID patients with neuropathic pain lasting at least 90 days and normal nerve conduction studies used a multimodal approach: skin biopsy to count small nerve fiber density, quantitative sensory testing, laser-evoked potentials, and electrochemical skin conductance measurement.10European Neurology. Small Fiber Neuropathy in Long COVID: A Cohort Study with Multimodal Assessment and Follow-Up Skin biopsy remains the most definitive diagnostic tool, since it directly visualizes the density of small nerve fibers in the skin. If you are dealing with persistent pain or burning sensations after COVID and your standard nerve test was normal, asking about a skin biopsy is a reasonable next step.
When the Autonomic Nervous System Goes Haywire
Small fiber damage does not just cause pain. Because small fibers also regulate involuntary functions like heart rate, blood pressure, digestion, and sweating, damage to these fibers can produce a constellation of autonomic symptoms collectively called dysautonomia. The most recognized form after COVID-19 is postural orthostatic tachycardia syndrome, or POTS, where standing up causes an excessive rise in heart rate along with lightheadedness, brain fog, and fatigue.
One proposed mechanism is that the virus triggers autoantibodies directed against autonomic nerve fibers and key receptors, including adrenergic and acetylcholine receptors.11PubMed Central. COVID-19 Induced Postural Orthostatic Tachycardia Syndrome (POTS): A Review A study comparing post-COVID patients with those diagnosed with myalgic encephalomyelitis/chronic fatigue syndrome found POTS in roughly 14% of post-COVID patients and abnormal sweat gland function, another marker of small fiber autonomic damage, in about 20%.12PubMed Central. Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome
A large study of long-COVID patients found that central sensitization, a state where the nervous system amplifies pain and sensory signals, was present in 81% of participants. Those with central sensitization had higher rates of anxiety, depression, fibromyalgia, and headaches, a greater burden of autonomic and sensory symptoms, more pronounced drops in brain blood flow on standing, and higher levels of the inflammatory marker IL-6.13PubMed Central. Central sensitization in long COVID: Associations with autonomic symptom burden, cerebral hypoperfusion, and neuroinflammation The interplay between autonomic dysfunction, neuroinflammation, and central sensitization creates a feedback loop that can make symptoms feel far out of proportion to what any single test reveals.
Loss of Smell as Nerve Damage
Early in the pandemic, sudden loss of smell became one of the signature symptoms of COVID-19. The mechanism turns out to be a form of nerve damage, though the virus gets at the olfactory system somewhat indirectly. SARS-CoV-2 enters the nasal lining through ACE2 receptors on sustentacular cells, the support cells that maintain the olfactory epithelium. Damage to these support cells, disruption of the tiny hair-like projections on olfactory neurons called cilia, and local inflammatory signaling all contribute to anosmia.14Korean Intraoperative Neuromonitoring Society. Neurophysiological mechanisms of anosmia: shared pathways in traumatic brain injury, chronic rhinosinusitis, COVID-19, and neurodegenerative disease
For most people, smell returns within weeks. But a subset of patients experience persistent smell loss lasting months or longer. Biopsies of the olfactory lining in these patients revealed something striking: even though no detectable SARS-CoV-2 virus remained, the tissue showed ongoing T-cell-mediated inflammation and a reduced number of olfactory sensory neurons relative to support cells.15Science Translational Medicine. Persistent post-COVID-19 smell loss is associated with immune cell infiltration and altered gene expression in olfactory epithelium The virus was gone, but the immune response it provoked kept damaging the tissue long afterward, a pattern that mirrors what happens in other post-COVID nerve problems.
Facial Nerve Palsy and Cranial Neuropathies
COVID-19 has also been linked to cranial nerve problems, the nerves that control the face, eyes, and parts of the head. Bell’s palsy, a sudden weakness or paralysis of the muscles on one side of the face, has been reported in three different clinical windows: as the very first sign of COVID-19 before any respiratory symptoms appear, during the acute phase of illness, or during recovery two to three weeks after other symptoms resolve.16PubMed Central. Facial nerve palsy: An early sign of COVID-19 Most cases of Bell’s palsy resolve on their own, but the association with COVID-19 means that a new facial droop during or shortly after a SARS-CoV-2 infection should be evaluated promptly.
When Other Viruses Wake Up
COVID-19 can also cause nerve damage indirectly by reactivating dormant viruses already living in your body. Herpes zoster, the virus responsible for shingles, lies dormant in nerve cells after a childhood chickenpox infection. When the immune system is stressed or suppressed, the virus can reactivate and cause painful blistering rashes along a nerve distribution. COVID-19 appears to trigger this reactivation in some patients, likely through transient depression of cell-mediated immunity.17PubMed Central. Herpes zoster might be an indicator for latent COVID 19 infection
In some cases, this goes beyond a typical shingles rash. Ramsay Hunt syndrome, a reactivation of herpes zoster affecting the facial nerve and ear, has been reported as the presenting symptom of COVID-19, sometimes appearing before any cough or fever.18PubMed Central. Zoster Cranial Polyneuropathy in a COVID-19 Patient For clinicians, this is a reminder that shingles flare-ups or new cranial nerve palsies during the pandemic era may signal an underlying or recent SARS-CoV-2 infection worth investigating.
Nerve Injuries in ICU Patients
Not all nerve damage from COVID-19 comes from the virus itself. Patients with severe illness who require intensive care face a separate risk: mechanical nerve compression from prolonged prone positioning. Placing patients face-down improves oxygen exchange in the lungs but puts sustained pressure on nerves that are vulnerable to compression, especially in the arms.
One rehabilitation center found that among 83 patients admitted after hospitalization for COVID-related respiratory failure, about 15% were diagnosed with peripheral nerve injuries. Nearly all had been placed in prone position during acute care. Across these patients, there were 21 focal nerve injury sites, with the majority in the upper limbs. The ulnar nerve was injured most often, followed by the radial nerve, sciatic nerve, brachial plexus, and median nerve.19PubMed Central. Injury-prone: peripheral nerve injuries associated with prone positioning for COVID-19-related acute respiratory distress syndrome These injuries are not caused by the virus at all but by the treatment necessary to keep severely ill patients alive. Awareness has improved positioning protocols in ICUs, but the risk remains real for patients requiring prolonged ventilation.
Autoantibodies That Persist
One of the more compelling recent findings helps explain why nerve symptoms linger for months or years in some long-COVID patients. Acute SARS-CoV-2 infection triggers the production of diverse autoantibodies, and individuals with neurocognitive symptoms show increased autoantibodies targeting both central and peripheral nervous system proteins.20Cell. A causal link between autoantibodies and neurological symptoms in Long COVID
A study of 977 long-COVID patients found that roughly one in four of those with neuropathy had elevated anti-ganglioside antibodies, which are antibodies that attack components of nerve cell membranes. None of the control long-COVID patients without neuropathy had these antibodies. When researchers tracked patients over time, they found that these antibody levels persisted in every subsequent blood sample, some extending more than a year and a half apart.21PubMed Central. Analysis of 977 Long COVID Patients Reveals Prevalent Neuropathy and Association with Anti-Ganglioside Antibodies The persistence of these antibodies offers one explanation for why neuropathic symptoms do not simply fade: the immune attack on nerves continues even after the virus is gone.
How COVID-19 Compares to Other Viral Nerve Damage
Viruses causing nerve problems is not a new phenomenon. Influenza, dengue, Zika, and various herpes viruses have all been associated with neurological complications. But a systematic review comparing COVID-19 to influenza and dengue across 24 studies concluded that COVID-19 exhibits the widest and most severe spectrum of neurological involvement. Influenza-associated neurological problems were less frequent and mostly involved encephalitis, seizures, meningitis, or GBS, with generally low mortality. Dengue caused a similar range of immune-mediated syndromes, but most patients recovered. COVID-19, by contrast, was distinguished by the breadth of its complications (spanning everything from anosmia to chronic inflammatory polyneuropathy to persistent nerve-conduction abnormalities) and, critically, by the persistence of symptoms in many survivors.22PubMed Central. Neurological Complications Associated With COVID-19 Compared to Other Viral Infections: A Systematic Review of Current Evidence
Vaccination and Nerve Damage
A fair question many people ask is whether COVID-19 vaccines can cause similar nerve problems. A prospective case-control study compared patients who developed small fiber neuropathy symptoms after COVID-19 infection with those who developed similar symptoms after vaccination. Both groups showed significant decreases in small nerve fiber density on skin biopsy compared to healthy controls. The infection group had a slightly higher rate of confirmed SFN (94% versus 79%), though the difference was not statistically significant.23PubMed Central. Small fiber neuropathy associated with COVID‐19 infection and vaccination: A prospective case–control study Vaccine-associated SFN exists but appears to be less common than infection-associated SFN. Both likely involve immune-mediated mechanisms rather than direct viral injury, since vaccines do not contain live virus. For most people, the overall neurological risk from the infection still outweighs the risk from vaccination.
Treatment Approaches and What Helps
Treatment for COVID-related nerve damage depends on the type and severity. For Guillain-Barré syndrome, standard treatments like plasma exchange and IVIG remain the frontline approach, applied the same way they would be for GBS triggered by any other cause. The earlier treatment begins, the better the outcomes tend to be.
For small fiber neuropathy and neuropathic pain, the picture is more individualized. The IVIG results mentioned earlier, where all nine treated patients improved and six had complete resolution of neuropathic symptoms, are promising but come from a small retrospective series.24PubMed Central. Post-COVID Small Fiber Neuropathy, Implications of Innate Immunity, and Challenges on IVIG Therapy IVIG is expensive and requires repeated infusions, and larger controlled trials are still needed before it becomes a standard recommendation. In the meantime, many clinicians use medications that are already established for neuropathic pain management, including certain antidepressants and anticonvulsants that calm overactive nerve signaling.
For dysautonomia and POTS, non-drug measures like compression garments, increased salt and fluid intake, and graded exercise programs are typically tried first, sometimes supplemented with medications that help stabilize heart rate or blood pressure. Persistent smell loss has been treated with olfactory training, where patients repeatedly sniff a set of strong odors to encourage regeneration of olfactory neurons, though recovery can be slow.
Emerging research has explored antioxidant supplementation and anti-inflammatory strategies aimed at reducing oxidative stress, which appears to play a role in both the severity and persistence of post-COVID neurological symptoms. These approaches remain experimental, and robust clinical trial data are limited. What is clear is that the diversity of nerve involvement after COVID-19 means there is no single treatment. The most effective path usually starts with getting the right diagnosis, particularly distinguishing small fiber neuropathy from large fiber problems, and then tailoring treatment to the specific mechanism at work.