Celiac Disease: Unmasking the Great Imitator

This transcript has been edited for clarity.

Let's start with a patient whom we might all see in primary care. Lucy is a 40-year-old lady who attends for an adoption medical after years, sadly, of unsuccessful attempts at natural conception. She's feeling stressed and anxious about the prospect of adoption, and this has worsened her symptoms of irritable bowel syndrome (IBS), with some associated weight loss.

Lucy has been living with IBS for several years now and struggles with intermittent cramping, abdominal pain, and diarrhea. She also recently fractured her wrist while snowboarding but otherwise has no past medical history of note. She's not on any prescribed medication and denies any illicit drug use. Of note, her father also has a history of IBS. Lucy is a married primary school teacher. She's a nonsmoker and drinks alcohol within recommended limits.

So, what are your thoughts here? Do you suggest talking therapies or pharmacotherapy for anxiety and stress? Do you discuss a low FODMAP diet for IBS symptoms and offer appropriate pharmacotherapy, such as antispasmodics? For those unfamiliar with FODMAP, it is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. They are basically short-chain carbohydrate sugars that are poorly absorbed in the small intestine, causing wind, bloating, and pain, particularly in people living with IBS. Importantly, FODMAPs are found in a variety of everyday foods in a normal healthy diet. Identifying them is not intuitive, but the list is not long, and dietary modification is quite straightforward.

Going back to Lucy, with her history of weight loss, would you want to exclude any lower gastrointestinal (GI) malignancy and consider further investigation, perhaps some blood work or even a colonoscopy? Or would you do something entirely different?

What Lucy has is celiac disease, which is often referred to as the great imitator. As a reminder, celiac disease is an abnormal gut mucosal response to glutens found in wheat, rye, and barley. This abnormal immune response leads to chronic inflammation of the small intestine with intestinal villous atrophy and lymphocyte infiltration. This can lead to malabsorption of nutrients such as vitamin D, vitamin B₁₂, folate, and iron, leading to clinical symptoms.

Celiac disease is common. Global prevalence is around 1.4%. There's a female preponderance, and the average age of diagnosis is in the fourth to sixth decade. Prevalence is higher in those with a background of autoimmune conditions such as thyroid disease or type 1 diabetes, or those with a family history of celiac disease. Going back to Lucy, her father's symptoms of IBS are likely also celiac disease.

Celiac disease is often undiagnosed or misdiagnosed in general practice unless we're actively considering the condition. Celiac disease should be excluded before a diagnosis of IBS is made in any individual, and all individuals with chronic GI symptoms should be considered for celiac screening. Around 75% of individuals remain undiagnosed, with an average diagnostic delay of around 10 years.

Importantly, the mode of presentation in older individuals tends to be nonclassical. In older individuals, those classic malabsorptive symptoms are often absent or mild. Anemia is more common in older individuals with celiac disease. Of course, this diagnosis may be overlooked when our attention in primary care is inevitably diverted to excluding any underlying GI malignancy.

However, in all age groups actually, the presentation of celiac disease has evolved over the past few decades. Overall, we are seeing fewer of those classic malabsorptive symptoms such as weight loss and diarrhea, and more nonclassic manifestations such as fatigue, bloating, and anemia. These are thought to be the more common presenting complaints these days.

Recent United Kingdom NICE (National Institute for Health and Care Excellence) guidance on celiac disease provides three key messages for us all working in primary care: Firstly, we should consider testing for celiac status in a much wider range of clinical scenarios. Secondly, we should refer all adults with positive serology for celiac disease to a GI specialist for endoscopic intestinal biopsy to confirm or exclude celiac disease. Thirdly, everyone living with celiac disease requires an annual review. I appreciate that there are workload implications for us here, but let me talk you through these three key messages.

What symptoms and signs might prompt us in primary care to check a celiac screen? GI features of celiac disease include indigestion, diarrhea, constipation, abdominal pain, bloating, and abdominal distension. Non-GI features include fatigue and dermatitis herpetiformis. Dermatitis herpetiformis is an intensely itchy rash with a symmetrical distribution over the scalp, the shoulders, the buttocks, and elbows and knees. It appears as a cluster of vesicles resembling herpes simplex viral infection. Other non-GI manifestations include anemia, osteoporosis, neuropathy, ataxia, short stature and delayed puberty in children, and importantly, infertility, which is very relevant to our patient Lucy.

Who should we be directly offering screening for celiac disease? Any of our patients with persistent, unexplained abdominal or GI symptoms should be screened for celiac disease. Similarly, children with faltering growth, our patients with prolonged fatigue, unexplained weight loss, severe or persistent mouth ulcers, or indeed those with unexplained iron, vitamin B₁₂ or folate deficiency, too. As mentioned already, anyone with an autoimmune background, type 1 diabetes, or autoimmune thyroid disease should also be screened, certainly at diagnosis. Anyone, of course, with IBS, as I've mentioned, should also be screened for celiac disease. Finally, first-degree relatives of people with celiac disease should also be screened.

What groups of individuals should perhaps we consider screening for celiac disease? If you have patients with a background of metabolic bone disorders (for example, osteoporosis or osteomalacia), consider screening for celiac disease. We should also consider screening those with unexplained neurologic symptoms, particularly peripheral neuropathy or ataxia. This has definitely changed my practice. I now add a celiac screen to my routine peripheral neuropathy screen.

For our patients like Lucy with unexplained subfertility or recurrent miscarriage, consider screening for celiac disease. Similarly, in patients with unexplained elevated liver function tests, dental enamel effects, or our patients living with Down or Turner syndrome, we should also consider screening for celiac disease. You can see we should be considering testing for celiac status in a much wider range of clinical scenarios.

When testing for celiac disease, we need to advise individuals to reintroduce gluten before testing: around 3 g of gluten daily for 2-4 weeks. This is equivalent, roughly, to about two slices of bread daily. We should check blood work then for total IgA and tissue transglutaminase (tTg)-IgA as our first-line test.

If individuals are IgA deficient, then we should consider checking IgG endomysial antibody. This is usually done automatically by our labs. IgA deficiency is 10 times more common in people living with celiac disease. We should also consider checking IgG endomysial antibodies if the tTg test is weakly positive.

As I've mentioned already, we should refer all patients with a positive tTg or endomysial antibody to gastroenterology for duodenal biopsies to confirm or exclude a diagnosis of celiac disease. Remember, this is a lifelong condition with potentially significant complications. Also, consider other blood work (such as full blood count, urea and electrolytes, liver blood tests, iron studies, calcium, and vitamin D) to rule out other sequelae of malabsorption.

Finally, let’s discuss management. A gluten-free diet is the definitive treatment for celiac disease. Most individuals report improvement within 2-6 months of excluding gluten. Ideally, all individuals should be referred to a specialist dietitian, though I appreciate that dietetic resources are disparate globally.

Patients with celiac disease were traditionally advised against oat consumption, owing to the resemblance between the peptide sequences in oats and gluten. But recent evidence suggests that oats are okay for the majority of people with celiac disease. Oats do not contain gluten but do contain the protein avenin, which may cause symptoms in a minority of people with celiac disease. Oats are often processed in the same environment as gluten-containing products, thus risking contamination. Gluten-free oats are available and can be introduced into a gluten-free diet.

UK guidance now recommends that gluten-free oats (50 g/day, equivalent to a bowl of porridge) can be introduced at diagnosis, and we can monitor individuals for symptoms. This is important, as oats are highly nutritious, providing a rich source of vitamins, minerals, and soluble fiber.

Finally, everyone living with celiac disease should be offered an annual review by a general practitioner or a dietitian, though I appreciate that there are workload and resource implications here. At this review, height and weight should be assessed. And review any ongoing symptoms alongside a dietary assessment. Also, at this annual review, we should consider assessing fracture risk using a tool, such as QFracture or FRAX, and assess the need for DEXA scanning.

We should assess calcium intake and recommend vitamin D supplementation as per public health guidance. We should consider additional blood tests to assess for nutritional deficiencies and associated autoimmune disorders, as I've mentioned already. We should also assess the risk of long-term complications. Lymphoproliferative and small bowel malignancies are more common in people with celiac disease, and, importantly, dietary adherence reduces this risk.

We should also discuss immunization. Additional immunization is recommended for people with celiac disease against pneumococcal disease. They also require an annual flu and COVID vaccination. Meningococcal vaccination may also be indicated in those with celiac disease known to have hyposplenism, which can be a complication of celiac disease.

Going back to Lucy, her underlying diagnosis is celiac disease, and this may have been driving her history of infertility as well as a recent wrist fracture. Her father has IBS-type symptoms and should also be screened for celiac disease.

A few quality improvement activities to close with: Audit your patients with IBS. Have they had serological testing for celiac disease? Looking at your registers of patients with type 1 diabetes and autoimmune thyroid disease, have they been offered serological testing for celiac disease? Finally, form a register of your patients with celiac disease and ensure at least annual recall to discuss adherence to a gluten-free diet and assess their risk of malabsorption and complications.

Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Medscape Family Medicine © 2025 WebMD, LLC

Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Cite this: Celiac Disease: Unmasking the Great Imitator - Medscape - Dec 05, 2025.