When a Blood Pressure Medication Mimics Celiac Disease

A blood pressure medication that millions of people take every day can cause intestinal damage so similar to celiac disease that even biopsies look nearly identical. A new case report published in Cureus documents yet another patient whose severe gastrointestinal symptoms and villous atrophy were caused not by gluten, but by olmesartan—a widely prescribed drug for hypertension.

For celiac families, this matters more than it might seem at first glance. Understanding that celiac-like intestinal damage can have other causes is crucial, both for those navigating their own diagnostic journeys and for anyone in the celiac community who takes blood pressure medication.

The Case: Celiac Disease Without the Celiac

The patient was a 53-year-old man who arrived at the hospital with profuse watery diarrhea, severe dehydration, and acute kidney injury. Doctors ran the standard workup: imaging, blood tests, stool cultures, and serological testing for celiac disease. Everything came back negative.

Then they performed duodenal biopsies. What they found looked textbook for celiac disease: villous blunting with marked intraepithelial lymphocytosis. These are the hallmark findings that gastroenterologists use to confirm a celiac diagnosis—flattened intestinal villi and an abnormal accumulation of immune cells in the intestinal lining.

But the celiac blood tests were negative. The patient wasn’t eating gluten. Something else was destroying his intestinal lining.

The culprit turned out to be olmesartan, a blood pressure medication the patient had been taking. After discontinuing the drug, his gastrointestinal symptoms resolved completely within two weeks, and his kidney function returned to normal.

Here’s where the case becomes especially compelling: the patient was later inadvertently re-exposed to olmesartan, and his symptoms came roaring back. This “rechallenge” strongly confirmed that the drug itself was causing the enteropathy.

What Is Olmesartan-Associated Enteropathy?

Olmesartan is an angiotensin II receptor blocker (ARB), a class of medications commonly prescribed for high blood pressure. It’s sold under brand names like Benicar and is used by millions of patients worldwide.

Olmesartan-associated enteropathy (OAE) is a rare but serious adverse reaction to this specific drug. What makes it particularly tricky is that it can develop years after a patient starts taking the medication—sometimes after a decade or more of use without any problems.

The symptoms are identical to active celiac disease: chronic diarrhea, weight loss, malabsorption, fatigue, and in severe cases, hospitalization for dehydration and electrolyte imbalances. The biopsy findings—villous atrophy and increased intraepithelial lymphocytes—are indistinguishable from celiac disease under the microscope.

The key difference? OAE is reversible. Stop the drug, and the intestines heal. The immune attack on the gut lining ceases.

Why This Matters for Celiac Families

As the parent of a child with celiac disease, I spend a lot of mental energy thinking about diagnosis—about what it means to have celiac confirmed, about the blood tests and biopsies that led to my son’s diagnosis, and about the vigilance required to keep him healthy.

This case report is a reminder that the diagnostic process is more complicated than it sometimes appears. Villous atrophy is not unique to celiac disease. Several conditions can cause the same intestinal damage, including:

• Olmesartan-associated enteropathy (as in this case)
• Tropical sprue (common in certain geographic regions)
• Autoimmune enteropathy (more common in children)
• Common variable immunodeficiency
• Giardiasis and other infections
• Collagenous sprue

For celiac patients who have been properly diagnosed and are following a strict gluten-free diet but still experiencing symptoms, this case raises an important consideration: Could a medication be contributing to ongoing intestinal damage?

The Diagnostic Challenge

One of the frustrating realities of celiac disease is that it can take years to diagnose. The symptoms overlap with so many other conditions, and not every physician thinks to test for it.

OAE presents the opposite problem: a patient with clear intestinal damage who tests negative for celiac disease. The researchers in this case emphasize that physicians need “high clinical suspicion” of OAE in patients with unexplained chronic diarrhea who are taking olmesartan.

The problem is that olmesartan is just one of many ARBs on the market. Others in the same drug class—like losartan, valsartan, and irbesartan—have not been associated with enteropathy to the same degree. This makes OAE a drug-specific reaction rather than a class effect, which can make it harder for physicians to recognize.

According to the case report authors, early recognition is essential. Delayed diagnosis means prolonged suffering, unnecessary invasive investigations, and potentially serious complications like the acute kidney injury seen in this patient.

What Should Celiac Patients and Families Know?

If you or a family member has celiac disease and also takes olmesartan for blood pressure, this case report is worth discussing with your healthcare provider. A few scenarios to consider:

For those with confirmed celiac disease: If you’re strictly gluten-free but still experiencing persistent gastrointestinal symptoms, and you happen to be taking olmesartan, it may be worth exploring whether the medication could be contributing. This doesn’t mean you should stop your blood pressure medication on your own—always consult with your doctor—but it’s a conversation worth having.

For those in the diagnostic process: If biopsy results show villous atrophy but celiac serologies are negative, OAE should be considered, especially if the patient is taking olmesartan. This could prevent a misdiagnosis and years of unnecessary dietary restriction.

For family members of celiac patients: Celiac disease has a strong genetic component, which means first-degree relatives are at higher risk. If a parent or sibling of someone with celiac disease develops chronic diarrhea and their biopsy shows villous atrophy, it might seem like an open-and-shut case. But negative celiac serology combined with olmesartan use should prompt consideration of OAE.

The Broader Lesson

This case report illustrates something I think about often as a celiac parent: medicine is complicated, and diagnosis is as much art as science.

Celiac disease is underdiagnosed. Studies consistently show that many people with celiac disease remain undiagnosed for years, suffering from symptoms that get attributed to irritable bowel syndrome, stress, or other causes.

But the opposite error—diagnosing celiac disease when something else is causing the intestinal damage—can also happen. A strict gluten-free diet is demanding. It affects every meal, every social event, every moment of food-related decision-making. Asking someone to follow that diet for life when they don’t actually have celiac disease is a significant burden.

For the celiac community, cases like this one are a reminder that we need both better awareness of celiac disease among physicians and better awareness of celiac mimics. The goal isn’t just more diagnoses—it’s accurate diagnoses.

Practical Takeaways

1. Know your medications. If you or a family member is on olmesartan (brand name Benicar), be aware that enteropathy is a rare but possible side effect.

2. Don’t stop medications without medical guidance. If you suspect a medication might be causing gastrointestinal problems, talk to your healthcare provider before making any changes.

3. Understand that villous atrophy has multiple causes. A biopsy showing intestinal damage is not automatically proof of celiac disease. Serology, clinical history, and response to dietary changes all factor into diagnosis.

4. Advocate for thorough evaluation. If celiac serologies are negative but symptoms persist, push for further investigation. OAE is rare, but it’s treatable—and treatment means simply switching to a different blood pressure medication.

5. Share this information. If you know someone with unexplained chronic diarrhea who takes olmesartan, this case report might be relevant to their care.

The good news in this case is that the patient recovered fully once the drug was stopped. His intestinal lining healed, his kidney function normalized, and his symptoms resolved. That’s the best possible outcome—and it only happened because someone thought to consider OAE as a possibility.

References

Nikolaeva A, Della Vecchia A. Olmesartan-Associated Enteropathy With Severe Diarrhoea and Acute Kidney Injury. Cureus. 2026;18(3):e104862. doi:10.7759/cureus.104862. Available at: https://pubmed.ncbi.nlm.nih.gov/41952938/