What Is Sprue? Types, Symptoms, and Treatment

Sprue is a general term for conditions in which the lining of the small intestine becomes damaged and loses the tiny finger-like projections (villi) that absorb nutrients from food. The result is malabsorption, meaning your body struggles to take in fats, vitamins, minerals, and other essentials even when your diet is adequate. There are several distinct diseases that fall under the sprue umbrella, and they differ sharply in their causes and treatment even though their intestinal damage can look remarkably similar under a microscope.

Where the Word Comes From

The term has odd roots. “Sprue” entered English medical writing in 1880, adapted from the Dutch word “spruw,” which had been used since at least the seventeenth century to describe a mouth condition in the Netherlands and Belgium similar to thrush.¹ An even earlier Dutch physician, Vincent Ketelaer, described “sprouw” in 1669 as an oral condition accompanied by extraordinarily copious stools.² Over the following centuries, doctors in tropical colonies noticed chronic diarrhea and wasting among residents and travelers, calling it “tropical sprue.” When a similar intestinal picture was recognized in temperate climates and linked to grain-based diets, it became “nontropical sprue” or celiac sprue. Today the word is mostly used by gastroenterologists as a shorthand for villous atrophy in the small bowel, regardless of cause.

Celiac Sprue

Celiac sprue, now more commonly called celiac disease, is the most familiar form. It is an autoimmune disorder triggered by gluten, the protein found in wheat, rye, and barley.³ When someone with celiac disease eats gluten, their immune system attacks the small intestinal lining, flattening the villi and deepening the crypts between them. This damage progressively shrinks the surface area available to absorb nutrients.

Genetics play a central role. Celiac disease is tightly linked to specific immune-system genes (HLA-DQ2 and HLA-DQ8), and without at least one of those gene variants, the disease essentially does not develop.³ But carrying the gene is not enough on its own; plenty of people have DQ2 or DQ8 and never develop the condition. The trigger is gluten, and a key player in the process is an enzyme called tissue transglutaminase (TG2). This enzyme chemically modifies fragments of gluten in a way that makes them far more provocative to the immune system.⁴ The body also produces antibodies against TG2 itself, which is why a blood test for those antibodies is one of the main ways doctors screen for the disease.

Symptoms of Celiac Sprue

The classic picture is chronic diarrhea, bloating, and weight loss driven by poor nutrient absorption.⁵ But celiac disease is often called a clinical chameleon because it can show up in ways that seem to have nothing to do with the gut. Iron-deficiency anemia that does not respond to supplements, bone thinning, a blistering skin rash known as dermatitis herpetiformis, nerve problems including a form of balance impairment called gluten ataxia, and liver enzyme abnormalities can all be the first sign. Some of these problems, particularly gluten ataxia, can become permanent if the disease is not caught in time.⁶

In children, the presentation can be different still. Growth failure, short stature, and delayed puberty are well-recognized complications of undiagnosed celiac disease in young people. Delayed puberty affects roughly one in five untreated pediatric celiac patients, though puberty typically begins within several months of starting a gluten-free diet.⁷ Because symptoms can be subtle or atypical at any age, many people go years before receiving a diagnosis.

Diagnosing Celiac Sprue

Screening typically starts with a blood test measuring antibodies to tissue transglutaminase (anti-tTG IgA). If those antibodies are elevated, the next step has traditionally been a small-bowel biopsy, which remains the gold standard. Pathologists grade the intestinal damage using the Marsh classification, a scale that ranges from mild increases in immune cells within the lining (Marsh I) through partial villous atrophy (Marsh II) to the severe flattening seen in advanced disease (Marsh III).⁸ In some cases, particularly in children, guidelines now allow a no-biopsy diagnosis when antibody levels are very high, but biopsy confirmation is still widely used in adults.⁹

Treatment and Mucosal Healing

A strict, lifelong gluten-free diet is the only established treatment. It sounds simple, but in practice it demands constant vigilance: gluten hides in sauces, processed foods, medications, and even lip balms. The good news is that for most people, the intestinal lining recovers substantially on this diet. A long-term follow-up study found that after a median of about eight years on a gluten-free diet, roughly four out of five patients achieved full mucosal healing, and about nineteen out of twenty showed at least partial recovery of their villi.¹⁰

That said, healing is not always complete at the microscopic level. Research in children on a long-term gluten-free diet has shown that while the overall shape of the villi normalizes, certain immune markers in the intestinal lining remain elevated compared to people without celiac disease.¹¹ These lingering immune signatures persist regardless of how long the diet is maintained, suggesting the gut retains a kind of memory of the disease. Practically, this reinforces why even small amounts of gluten can reignite the inflammatory process.

Beyond the gut, the psychological burden of managing celiac disease is real. Anxiety, depression, and persistent fatigue are common before diagnosis and contribute to reduced quality of life. While many patients feel substantially better within months of eliminating gluten, a portion continue to struggle with psychological symptoms, which in turn can erode dietary adherence and set up a frustrating cycle.¹²

Tropical Sprue

Tropical sprue produces villous atrophy that looks a lot like celiac disease under a microscope, yet its cause is entirely different.¹³ Rather than an autoimmune reaction to gluten, tropical sprue is thought to begin with an intestinal infection, whether bacterial, viral, or parasitic, that kicks off a cycle of gut damage and bacterial overgrowth.¹⁴ The exact cause has never been pinned down to a single organism, which is one reason the disease remains poorly understood compared to celiac disease.¹⁵

The condition is seen mainly in people living in or returning from tropical regions, particularly South and Southeast Asia, the Caribbean, and parts of Central America. It tends to start with an acute episode of diarrhea that never fully resolves, then slowly progresses to chronic malabsorption. Because the damaged intestine has trouble absorbing folic acid and vitamin B12, anemia is especially common and can become severe, producing fatigue, mouth sores, and neurological symptoms.¹⁶

Telling Celiac and Tropical Sprue Apart

This distinction matters a great deal because the treatments are completely different. Clinically, the two conditions share many features: chronic diarrhea, bloating, weight loss, and abnormal fat in the stool occur at similar rates in both. A systematic review found that no single symptom reliably separates them, though celiac patients were more likely to present with short stature and dyspepsia, while tropical sprue patients were more likely to have anemia and abnormal results on nutrient absorption tests.¹⁷

The most useful differentiator is serology. Antibodies against tissue transglutaminase and endomysium are present in most celiac patients but absent in tropical sprue.¹⁸ Biopsy patterns also differ: celiac disease tends to produce more severe, uniform villous damage (higher Marsh grades), while tropical sprue more often shows milder, patchy changes with an increase in certain immune cells that taper off deeper in the intestine rather than intensifying.¹⁷

Treating Tropical Sprue

Unlike celiac disease, tropical sprue is treated with antibiotics and nutritional supplementation rather than a restricted diet. Tetracycline (or a related antibiotic) is the traditional mainstay, aimed at clearing the bacterial overgrowth that perpetuates the intestinal damage. Alongside the antibiotic, folic acid replacement is given to correct the deficiency and help the intestinal lining regenerate. Studies have shown that this combination produces clinical improvement and restoration of normal nutrient absorption.¹⁹ Vitamin B12 injections may also be needed when deficiency is severe. Most patients recover fully with treatment, though some require a prolonged course of antibiotics lasting several months.

Refractory Celiac Disease

A small minority of celiac patients do not improve on a strict gluten-free diet, or they improve initially and then relapse despite continued adherence. This is called refractory celiac disease, and it comes in two forms. Type 1 looks like ordinary celiac disease at the cellular level but simply does not respond to dietary measures. Type 2 is more ominous: it involves the expansion of abnormal, clonal immune cells in the intestinal lining, which makes it a precancerous condition.²⁰

The distinction between the two types requires specialized lab testing on biopsy tissue to identify whether the immune cells in the gut lining have an abnormal pattern or show evidence of clonal expansion.²¹ This matters because type 2 refractory celiac disease carries a real risk of progressing to a rare but aggressive cancer called enteropathy-associated T-cell lymphoma. In one treatment series, about one in six patients with type 2 disease developed this lymphoma, and all of those patients died.²²

For both types, corticosteroids, most commonly budesonide, are used as first-line therapy.²³ For type 2, more aggressive immunosuppressive drugs may be added to try to eliminate the abnormal cell population before it transforms into lymphoma. This is one of the areas where celiac disease stops being a “just avoid gluten” condition and becomes a serious medical challenge requiring specialist care.

Drug-Induced Sprue-Like Enteropathy

Not all sprue is caused by gluten or tropical infections. Certain medications can produce intestinal damage that mimics celiac disease. The best-documented culprit is olmesartan, a blood pressure drug in the angiotensin receptor blocker class. Patients on olmesartan can develop severe diarrhea, weight loss, and nausea, with biopsies showing villous atrophy and increased immune cells that are essentially indistinguishable from celiac disease.²⁴ The key difference is that celiac antibody tests come back negative and a gluten-free diet does not help.²⁵

The fix is straightforward: stop the drug. Case reports have documented that sprue-like symptoms resolve when olmesartan is replaced with a different blood pressure medication.²⁶ The tricky part is thinking of it in the first place. If you or your doctor do not consider the medication as a possible cause, you can end up going through extensive and unnecessary testing, possibly even being misdiagnosed with celiac disease. This is a good reminder that any new or worsening digestive symptoms in someone on long-term medications deserve a look at the drug list.

Other Rare Causes of Villous Atrophy

A handful of other conditions can produce sprue-like intestinal changes. Autoimmune enteropathy is one, where the immune system attacks the gut lining in a pattern that can resemble celiac disease but is not triggered by gluten. Common variable immunodeficiency (CVID), a condition where the body cannot produce enough antibodies, can also cause chronic diarrhea with villous atrophy and increased immune cells in the gut. The intestinal damage in CVID has its own distinguishing features, particularly a near-absence of a specific type of immune cell called plasma cells, along with enlarged clusters of immune tissue in the gut wall.²⁷

Clinically, these conditions can be hard to separate without specialized testing. Patients with CVID tend to have a history of recurrent respiratory infections and very low levels of multiple antibody types in their blood, which helps point toward the right diagnosis.²⁸ The takeaway is that when someone presents with chronic diarrhea and villous atrophy on biopsy but celiac serology is negative and a gluten-free diet does not work, the diagnostic net needs to widen considerably.

Therapies Beyond the Gluten-Free Diet

For celiac disease, the gluten-free diet works well when it is followed strictly, but strict adherence is hard. Gluten contamination is common in restaurants and packaged foods, and some patients remain symptomatic despite doing everything right. This has driven substantial interest in non-dietary treatments. Research is moving along several fronts: enzymes that break down gluten in the stomach before it reaches the small intestine, drugs that tighten the intestinal barrier to prevent gluten fragments from slipping through, and approaches aimed at reprogramming the immune response so it no longer reacts to gluten at all.²⁹

None of these have yet reached the point where they can replace the gluten-free diet, but the hope is that they could eventually serve as an adjunct, protecting against accidental exposure or perhaps one day allowing patients to eat gluten-containing foods safely.³⁰ Several candidates are in clinical trials, and this is arguably the most actively researched area in celiac disease right now. For tropical sprue, the existing antibiotic-plus-folate approach is effective enough that there is far less urgency to develop alternatives.

Monitoring Recovery Without a Biopsy

Repeat biopsies to confirm that the gut has healed are informative but invasive. Researchers have long looked for simpler ways to track how the intestinal lining is doing. One approach measures how the gut handles two different sugars: one that should pass through damaged areas (lactulose) and one absorbed through intact villi (mannitol). The ratio between them in urine correlates well with histological grading of the intestinal mucosa, and it tracks reliably as people improve on a gluten-free diet.³¹ While this particular test is not yet standard practice everywhere, it illustrates the broader push toward noninvasive monitoring tools that could spare patients from repeated endoscopies. Blood antibody levels also tend to fall on a successful gluten-free diet and are used routinely to gauge dietary adherence, though they do not always perfectly mirror what is happening at the tissue level.