Several viruses in the herpes family can cause stomach and abdominal pain, though the routes vary widely depending on which virus is involved and where in the body it becomes active. Herpes simplex virus (HSV-1 and HSV-2), varicella-zoster virus (VZV, the cause of chickenpox and shingles), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) have all been documented as causes of abdominal pain through mechanisms ranging from direct tissue damage to nerve inflammation. The connection is more common in people with weakened immune systems, but it can happen in otherwise healthy individuals too, and it is frequently missed or misdiagnosed.
HSV and the Esophagus
One of the more direct ways a herpes simplex infection produces stomach-area pain is through herpes esophagitis, where HSV-1 infects the lining of the esophagus and creates shallow ulcers. These ulcers typically cause pain behind the breastbone during swallowing, but they can also produce what feels like upper-stomach pain. A published case report described a patient whose main symptom was epigastric pain, the kind of discomfort you’d associate with an ulcer or acid reflux rather than a viral infection.1PubMed Central. Epigastric pain associated with herpes esophagitis: case report The overlap with common gastrointestinal complaints is part of what makes herpes esophagitis easy to overlook.
Diagnosing herpes esophagitis usually requires an endoscopy with a biopsy. HSV tends to produce characteristic round, shallow ulcers on mucosa that otherwise looks fairly normal. A real-time PCR assay tested on esophageal biopsy specimens detected HSV-1 in nearly all histologically confirmed cases of herpetic esophagitis, with a negative predictive value above 95%, meaning a negative result is quite reliable for ruling the virus out.2PubMed Central. Virological diagnosis of herpes simplex virus 1 esophagitis by quantitative real-time PCR assay Varicella-zoster virus can also infect the upper gastrointestinal tract but tends to look different on endoscopy, producing hemorrhagic ulcers with prominent bleeding and unusual cell damage deep in the stomach glands, a pattern not typically seen with HSV.3The American Journal of Surgical Pathology. Clinicopathologic Features of Varicella Zoster Virus Infection of the Upper Gastrointestinal Tract
How Herpes Reaches the Gut’s Nervous System
Beyond directly infecting the lining of the esophagus or stomach, herpes viruses can cause gastrointestinal problems by targeting the enteric nervous system, the vast network of neurons embedded in the walls of your digestive tract. This network controls everything from the rhythmic contractions that push food along to the regulation of blood flow and secretions. When herpes viruses infect those neurons, things can go seriously wrong.
Animal research has shown that after being swallowed, HSV-1 can infect neurons in the myenteric plexus, a key part of the enteric nervous system. The infected neurons produce chemical signals that recruit immune cells called macrophages. Those macrophages then release reactive molecules that damage the neurons themselves, leading to disordered gut motility, essentially making the intestines unable to contract and move contents properly.4PubMed Central. Herpes Simplex Virus Type 1 Infects Enteric Neurons and Triggers Gut Dysfunction via Macrophage Recruitment Separately, research has found that HSV-1 can also reach the enteric nervous system through a less intuitive path: spreading from a genital infection through the dorsal root ganglia (nerve clusters near the spine) into the autonomic nerves supplying the colon. In mouse models, this caused an intense inflammatory response, destruction of enteric neurons by immune cells, and permanent loss of the rhythmic contractions the colon needs to function.5PubMed Central. Viral Spread to Enteric Neurons Links Genital HSV-1 Infection to Toxic Megacolon and Lethality
Even when the virus appears to enter a dormant state in gut neurons, the immune system’s ongoing surveillance can continue to cause trouble. Research has demonstrated that HSV-1 persisting in enteric neurons leads to ongoing expression of viral proteins, which in turn draws in immune cells that attack the neurons and can predispose the gut to long-lasting muscle and nerve dysfunction.6FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY. Persistent Herpes Simplex Virus Type 1 Infection of Enteric Neurons Triggers CD8(+) T Cell Response and Gastrointestinal Neuromuscular Dysfunction Another study found that after HSV-1 reached the gut neurons of rats, there were measurable changes in intestinal muscle contractions and chemical signaling for weeks, even when no visible damage appeared on tissue examination.7Gastroenterology. Herpes Simplex Virus Type 1 Infection of the Rat Enteric Nervous System Evokes Small-Bowel Neuromuscular Abnormalities
Most of these enteric nervous system findings come from animal studies, and translating them to humans requires some caution. But they offer a plausible explanation for why some people with herpes infections develop gastrointestinal complaints that are hard to pin down with standard testing: the virus may be disrupting the gut’s own nervous system without leaving an obvious footprint on the tissue surface.
Shingles and Abdominal Pain, Sometimes Without a Rash
Varicella-zoster virus deserves special attention because its reactivation as shingles is one of the most common herpes-related causes of abdominal pain, and one of the most commonly misdiagnosed. When shingles affects nerve roots that supply the abdominal wall (thoracic dermatomes roughly from the mid-back to the waist), it can produce intense pain in the chest, flank, or abdomen that arrives days before any rash appears, or in some cases, with no rash at all.
The rash-free version is called zoster sine herpete, and it presents as nerve pain without the telltale blisters. Patients can experience neuralgia in the distribution of cranial nerves, spinal nerves, or even visceral and autonomic nerves, all without visible skin involvement, which makes clinical diagnosis extremely difficult.8PubMed Central. Zoster sine herpete: a review A case report described two patients who experienced severe, intractable abdominal pain without any rash or visible herpes, and standard abdominal imaging found no tumors or organ abnormalities.9PubMed Central. Diagnosis and treatment of varicella-zoster virus infection with herpetic visceral neuralgia without rash: A case report One of those patients had been dealing with the pain for two months before the actual cause was identified.
This diagnostic blind spot has real consequences. A published case described a 62-year-old woman who came to the emergency room with right upper quadrant abdominal pain and no rash. She was diagnosed with acute cholecystitis and underwent a laparoscopic gallbladder removal. Only afterward, when clusters of blisters appeared on her right abdominal skin, was the true diagnosis of herpes zoster made clear. The surgery had been unnecessary.10PubMed Central. Herpes zoster as a diagnostic pitfall leading to an unwarranted cholecystectomy: a case report
Shingles can also affect the gut itself, not just the nerves of the abdominal wall. A case of a 75-year-old woman documented how herpes zoster caused acute colonic pseudo-obstruction, a condition where the large intestine stops working even though there is no physical blockage. The mechanism is thought to involve the virus interfering with the autonomic nervous system or even directly invading the gut’s muscle layers and nerve plexus.11Journal of Neurogastroenterology and Motility. A Rare Cause of Acute Colonic Pseudo-obstruction: Ogilvie’s Syndrome Caused by Herpes Zoster
Other Herpesviruses That Cause Abdominal Pain
HSV and VZV get most of the attention when it comes to gut involvement, but the herpes virus family includes eight human viruses, and several of the others can produce abdominal symptoms too.
Cytomegalovirus, or CMV, is a leading cause of colitis in immunocompromised patients, and abdominal pain is a core symptom. CMV replicates in the cells lining blood vessels in the gut, which can trigger inflammation, ulcer formation, and in severe cases, blood clots that cut off blood supply to sections of the intestine.12Journal of Acute Care. Case of Cytomegalovirus Colitis: A Rare Cause of Abdominal Pain and Diarrhea in an Adult Patient While CMV colitis has traditionally been considered a problem for transplant recipients and people with advanced HIV, it can occasionally affect people with no obvious immune deficiency. A case of a 15-year-old boy who had recently recovered from a COVID-19 infection documented CMV colitis causing fever, abdominal pain, and bloody stools, confirmed by tissue biopsy.13PubMed Central. Cytomegalovirus colitis as intestinal obstruction in an immunocompetent adolescent: a case report and literature review
Epstein-Barr virus, the cause of infectious mononucleosis, is another common herpesvirus that can produce abdominal pain. Most people associate mono with a sore throat and fatigue, but the virus frequently causes the spleen to swell, which leads to left-sided upper abdominal discomfort. Less commonly, EBV can cause acute hepatitis, and case reports have described patients presenting with right upper quadrant pain, a tender enlarged liver, and abnormal liver function tests as their primary mono symptoms.14PubMed Central. Abdominal pain in acute infectious mononucleosis
Human herpesvirus 8, which causes Kaposi’s sarcoma, rounds out the list. Though the condition is rare and mainly affects people with HIV, Kaposi’s sarcoma can develop in the gastrointestinal tract and cause pain, bleeding, or bowel obstruction. A documented case involved a patient who presented with acute right lower quadrant pain and was found to have Kaposi’s sarcoma causing a small bowel obstruction with perforation.15PubMed Central. Kaposi’s Sarcoma Presenting as Acute Small Bowel Obstruction Diagnosed on Multidetector Computed Tomography with Histopathological Correlation
HSV-2 and Pelvic or Lower Abdominal Pain
Genital herpes caused by HSV-2 can produce lower abdominal or pelvic pain through a different route than the gut-nerve mechanisms described above. HSV-2 has a well-documented association with inflammation of the nerve roots and spinal cord at the sacral level, a condition called radiculomyelitis. Symptoms include pain, weakness, bladder and bowel dysfunction, and sensory loss in the lower body.16PubMed Central. Herpes Simplex Virus Type 2 Radiculomyelitis Disguised as Conversion Disorder The pain from sacral radiculomyelitis can radiate into the pelvis, lower abdomen, and lower back. In at least one documented case, a recurrent HSV-2 outbreak caused sacral nerve inflammation severe enough to paralyze the bladder, leading to urinary retention.17Austin Journal of Obstetrics and Gynecology. Elsberg Syndrome in Pregnancy: A Case of Acute Urinary Retention Due to Sacral Myeloradiculitis Resulting From a Recurrent Herpes Simplex Virus-2 Infection
Because the sacral nerves control both the pelvic organs and sensation in the lower abdomen, HSV-2 flares that involve these nerve roots can produce deep pelvic aching, cramping, or stabbing pain that may not obviously connect to a genital herpes outbreak. Patients and even clinicians sometimes attribute this pain to urinary tract infections, ovarian cysts, or functional bowel disorders before considering the virus as a cause.
The Immunocompromised Are Hit Hardest
Nearly all of the more severe gastrointestinal herpes presentations cluster in people whose immune systems are suppressed, whether from HIV, organ transplant medications, cancer chemotherapy, or autoimmune treatments. People undergoing chemotherapy for lymphoma, for instance, appear to be at particular risk for disseminated varicella-zoster infections that begin with abdominal pain. A report of three lymphoma patients described how all of them initially presented with abdominal pain before any skin eruption appeared, and two also developed liver inflammation. All had severely low immune-cell counts at the time of diagnosis.18PubMed Central. Disseminated herpes zoster infection initially presenting with abdominal pain in patients with lymphoma undergoing conventional chemotherapy: A report of three cases
VZV can directly infect the stomach lining in immunocompromised patients, producing painful gastric ulcers. Two cancer patients, one with chronic lymphocytic leukemia and one with non-Hodgkin lymphoma, presented with upper abdominal pain and vomiting. Endoscopy revealed multiple round ulcers in the stomach, and PCR testing confirmed varicella-zoster virus as the cause in both cases.19Revista Española de Enfermedades Digestivas. Gastric varicella: two cases in cancer patients
People with inflammatory bowel disease who take immunosuppressive medications face a double bind. HSV colitis in this population often mimics the symptoms of an IBD flare, presenting as fever, abdominal pain, diarrhea, and rectal bleeding, typically without any telltale cold sores or genital lesions to suggest a viral cause.20PubMed Central. Concomitant herpes simplex virus colitis and hepatitis in a man with ulcerative colitis A clinician seeing those symptoms in someone with known ulcerative colitis or Crohn’s disease would naturally think the underlying disease is worsening and might escalate immunosuppressive therapy, which is exactly the wrong move if the real problem is a viral infection that thrives when immunity is suppressed.
Why Herpes-Related Abdominal Pain Gets Missed
A recurring theme across these cases is diagnostic delay. Herpes viruses are simply not high on the list of suspects when someone walks into a clinic or emergency room with stomach pain. The diagnostic framework for abdominal pain tends to start with the most common mechanical and inflammatory causes: appendicitis, gallstones, ulcers, bowel obstruction, kidney stones, pancreatitis. Viral infections of the gut lining or gut nerves are considered uncommon enough that they rarely enter the workup unless other explanations have been exhausted or specific clues emerge.
The biggest pitfall is shingles presenting before the rash, or without a rash entirely. The pain from abdominal-wall shingles can perfectly mimic gallbladder disease, kidney stones, or even a heart attack depending on the dermatome involved. The cholecystectomy case described earlier is not unique; the medical literature contains multiple reports of unnecessary surgeries triggered by herpes zoster pain in the absence of visible skin lesions.10PubMed Central. Herpes zoster as a diagnostic pitfall leading to an unwarranted cholecystectomy: a case report
For HSV and CMV, the diagnosis almost always requires tissue biopsy from an endoscopy. Blood tests for these viruses are common, but a positive antibody result just means someone has been exposed at some point, which is true for the majority of adults worldwide. Proving that the virus is actively causing a gastrointestinal problem means demonstrating its presence in the affected tissue. That is a higher bar than most patients or even many primary care physicians expect, and it means herpes-related gut involvement may only be identified when someone is sick enough to warrant invasive testing.
Shingles Pain That Outlasts the Infection
Even after the acute infection resolves, herpes zoster can leave behind persistent pain known as postherpetic neuralgia. The underlying cause involves lasting damage to both the peripheral nerves and the spinal cord itself. Skin biopsies in people with postherpetic neuralgia have shown severe loss of pain-sensing nerve fibers, and autopsy studies have found shrinkage of the part of the spinal cord that processes sensory input from the affected area.21Gastroenterology. Mechanisms of pain and itch caused by herpes zoster (shingles) When the affected dermatome is in the abdominal region, this means ongoing stomach-area pain that can last months or years after the shingles rash has healed. The pain is often burning, stabbing, or electric in character, and it can be triggered or worsened by light touch on the skin overlying the affected nerve, a frustrating feature that ordinary painkillers do little to relieve.
For someone who had abdominal shingles and continues to have pain long after, the challenge is that repeated imaging and blood work will keep coming back normal. The problem is in the nerves themselves, not in the organs they sit near. Recognizing the pattern and connecting it to a prior shingles episode is the key to getting appropriate treatment, which typically involves nerve-pain medications rather than the standard toolkit for stomach complaints.