Coeliac disease: the atypical presentations that get missed

Coeliac Disease: The Atypical Forms Often Overlooked

Coeliac disease is no longer solely a childhood illness characterised by diarrhoea and weight loss. Today, it's diagnosed just as frequently in adults, and a significant proportion of these individuals lack the classic gastrointestinal symptoms entirely. This is one reason why, in Denmark, many years often pass between the onset of initial signs and a confirmed diagnosis. It's estimated that about 1% of the population has coeliac disease, but only a small fraction are diagnosed and treated.

You've probably heard of coeliac disease referred to as a gluten allergy. This isn't entirely accurate. It's an autoimmune disease where your own immune system reacts to gluten by attacking the lining of the small intestine. This damage can persist for years without causing the symptoms you might expect.

The Classic Symptoms Everyone Knows

The classic description remains valid: chronic diarrhoea, bloating, fatty stools, weight loss, and, in children, failure to thrive. However, in Denmark, only one-third of newly diagnosed adults present in this way. The other two-thirds have what we call atypical or silent forms.

The Atypical Forms Often Missed

You can have coeliac disease without any abdominal symptoms at all. Here are the signs we've learned to recognise in clinical practice, as they are often the only clue leading to a diagnosis:

• Iron deficiency anaemia that doesn't resolve. If you take iron supplements without effect, the cause might be that your intestinal lining isn't absorbing iron properly.
• Osteoporosis at an unusually young age. Coeliac disease can lead to vitamin D deficiency and poor calcium absorption.
• Elevated liver enzymes without another explanation.
• Unexplained fatigue and brain fog.
• Recurrent mouth ulcers (aphthae).
• Headaches, depression, or anxiety.
• Infertility or recurrent miscarriages.
• Peripheral neuropathy (tingling and burning in the feet).
• Itchy skin rash (dermatitis herpetiformis).

If you experience any of these without another good explanation, it's worth getting tested for coeliac disease, even if your stomach feels completely normal.

Why Does It Occur?

Coeliac disease develops when the immune system of genetically predisposed individuals reacts to gluten. Gluten is the protein fraction found in wheat, rye, and barley. This reaction damages the small villi (finger-like projections) that line the inside of the small intestine and are responsible for nutrient absorption. When the villi are damaged, the intestine cannot properly absorb iron, calcium, fat-soluble vitamins, or folic acid.

Almost everyone with coeliac disease carries a specific gene variant (HLA-DQ2 or HLA-DQ8). However, this is only a predisposing factor. Approximately one-third of Danes have one of these gene variants, and only a small fraction develop the disease. What triggers it precisely is not fully understood. An intestinal infection, pregnancy, or other stressor might be a trigger.

How Is the Diagnosis Made?

Diagnosis requires two things, and the order is important:

1. Blood tests while you are still eating gluten. The most important is anti-transglutaminase IgA (TTG-IgA) along with total IgA. If you have already started a gluten-free diet, the test results will normalise, and the diagnosis cannot be made.
2. Gastroscopy with biopsies from the small intestine. We take four to six small tissue samples from the duodenum (the first part of the small intestine). A pathologist assesses whether there is villous atrophy according to the Marsh classification.

In children with classic symptoms and very high antibody levels, a biopsy can sometimes be omitted, but in adults, it is almost always recommended to establish a baseline for comparison during follow-up.

Treatment

There is only one effective treatment: a lifelong gluten-free diet. This sounds simple but is challenging in practice because gluten hides everywhere – in soy, spice mixes, medicines, and supplements. A dietitian is invaluable during the first year.

Within six to twelve months, most people begin to experience:

• Return of energy
• Normal blood count (if iron supplements are also given)
• Weight gain for those who were underweight
• Normalisation of antibodies in the blood
• Regrowth of villi in the intestine, confirmed by a follow-up biopsy after one to two years

It's important to know that even small amounts of gluten can maintain the inflammation. There's no such thing as a "little cheat day" with coeliac disease.

When Should You See a Doctor?

Contact your GP for a coeliac disease test if:

• You have iron deficiency anaemia that doesn't improve with iron supplements.
• You have persistent abdominal symptoms similar to irritable bowel syndrome, especially if they started in adulthood.
• You have a first-degree relative with coeliac disease (the risk is 10%).
• You have type 1 diabetes, autoimmune thyroid disease, or Down syndrome.
• You have unexplained osteoporosis, infertility, or elevated liver enzymes.

For most, a diagnosis brings relief, as they suddenly have an explanation for years of puzzling symptoms.

Frequently Asked Questions

Can I have non-coeliac gluten sensitivity instead of coeliac disease? Yes, this exists. However, the diagnosis first requires that coeliac disease is ruled out with blood tests and a biopsy while you are still eating gluten. Otherwise, you won't know if you have a more serious autoimmune condition.

Does coeliac disease go away? No. It is lifelong. Children diagnosed who later resume eating gluten will experience symptoms again and develop damage.

Does coeliac disease increase the risk of cancer? Treated and controlled coeliac disease carries only a slightly increased risk of intestinal lymphoma. The risk is highest for those who do not adhere to the diet or have a rare, refractory form. This is one reason for follow-up with your GP.

Should my children be tested? First-degree relatives should be tested. This is done with a blood test, and if there is suspicion, a referral for gastroscopy follows.

References

1. Husby S, Koletzko S, Korponay-Szabó I, et al. European Society Paediatric Gastroenterology, Hepatology and Nutrition Guidelines for Diagnosing Coeliac Disease 2020. J Pediatr Gastroenterol Nutr. 2020;70(1):141-156. PubMed
2. Lebwohl B, Sanders DS, Green PHR. Coeliac disease. Lancet. 2018;391(10115):70-81. PubMed
3. Sundhed.dk. Cøliaki (lægehåndbogen).
4. Al-Toma A, Volta U, Auricchio R, et al. European Society for the Study of Coeliac Disease (ESsCD) guideline for coeliac disease and other gluten-related disorders. United European Gastroenterol J. 2019;7(5):583-613. PubMed

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This article provides general information and does not replace medical consultation. Contact your GP if you experience symptoms.