Gluten intolerance, allergy or something else? Diagnosing coeliac disease

The symptoms of coeliac disease vary between individuals, but usually include diarrhoea, vomiting, stomach cramps and skin rashes.

It’s a common condition, thought to affect around one in every 100 people in the UK. However, the actual figure is estimated to be a lot larger, as some people with symptoms do not think they’re severe enough to see their doctor.

If you have unexplained gastric symptoms and/or regular skin rashes, you may have heard of coeliac disease when researching your symptoms. In this article, we explain what coeliac disease is, how you can be tested for it and how you can manage it.

What is coeliac disease?

Coeliac disease is an autoimmune disease, which means that the immune system attacks innocent substances or healthy parts of the body by mistake.

In the case of coeliac disease, the immune system mistakenly thinks that a substance within gluten, called gliadin, is a threat.

Gluten is a type of protein that gives certain foods a chewy texture. It’s found in wheat, barley and rye, and naturally occurs in foods such as bread, pasta, cakes, biscuits, pastry goods and breakfast cereals.

It can also be found in foods you may not always associate with wheat, barley or rye, such as sauces, soups and condiments, where they’re often used as thickeners.

Gluten can also enter the body through “cross-contamination”, where utensils or foods come into contact with gluten.

If a person with coeliac disease eats food containing gluten, or food that has been contaminated by utensils or other gluten-containing food, the immune system starts to attack this perceived threat. It produces antibodies against gliadin that cause the small intestine to swell and become red and inflamed. Over time, this damages the lining of the small intestine.

In a healthy person, the small intestine is lined with millions of structures called villi and microvilli. These are tiny hair-like protrusions that increase the surface area of the small intestine, allowing more nutrients to be absorbed.

These structures flatten when they become damaged, decreasing the surface area making it harder for the small intestine to absorb essential nutrients.

Is coeliac disease an intolerance or an allergy? What’s the difference?

There are certain foods or substances in foods that can cause an intolerance or an allergy in certain people. They often cause gastrointestinal complaints such as diarrhoea, nausea, sickness, bloating and abdominal pain.

As the symptoms can be similar, it’s easy to confuse the two. But a food allergy is more severe than a food intolerance.

Food allergies can cause severe reactions called anaphylaxis, which causes breathing difficulties and swollen lips. Foods that commonly cause allergies include peanuts and shellfish. Allergies can be life-threatening even if only a small amount of the offending food is eaten.

A food intolerance can cause mild or severe gastrointestinal symptoms, but they’re not life-threatening. Sufferers may be able to tolerate a small amount of offending food without experiencing symptoms. Lactose intolerance, for example, is an intolerance to the natural sugar found in cow’s milk and dairy products that is not life-threatening.

Although some people can be intolerant or allergic to gluten, coeliac disease is different.

Coeliac disease is not an intolerance or an allergy to gluten. Instead, it is an abnormal reaction by the immune system to gluten in foods.

What are the signs and symptoms of coeliac disease?

Coeliac disease causes the following gastrointestinal symptoms:

• Diarrhoea
• Oily stools with an offensive smell that are difficult to flush
• Pain in the abdomen
• Bloating
• Excess wind
• Indigestion
• Vomiting
• Constipation

You may experience all or some of these symptoms and they may vary from mild to severe.

It can also cause a skin condition called dermatitis herpetiformis. This is caused by the immune system reacting to gluten and results in an itchy skin rash. It’s most common on the buttocks and joints such as the elbows and knees, but can appear anywhere on the body.

It can be difficult knowing whether your symptoms are caused by IBS, a food intolerance, coeliac disease or something else.

This short online assessment from Coeliac UK will help to make things clearer. It won’t diagnose you, but it will help to inform you as to whether or not you should speak to your doctor about getting tested.

How is coeliac disease diagnosed?

If your doctor suspects that you may have coeliac disease, they will run some specific tests or refer you to a specialist.

First off, you will have a blood test. This test is looking for the presence of antibodies to gliadin in your blood. If the results are positive, or if your doctor still thinks you have coeliac disease despite your blood tests being negative, you will have a biopsy.

In order to take biopsies of the small intestine, you will need to have a procedure called an endoscopy, carried out by a gastroenterologist.

This involves passing a small tube down your throat into your small intestine whilst you’re sedated to make you relaxed.

During the diagnosis phase, you will need to continue to eat foods containing gluten so that the tests see a true representation of how your body reacts to gluten.

If your results prove that you have coeliac disease, you will be tested further to see if you’re suffering from any nutrient deficiencies. This involves a further blood test. You may also have scans to see if your bones have started to become weak from malnutrition.

You may also be referred to a nutritionist who can help you find the right diet to support your symptoms and diagnosis.

What causes coeliac disease? Does it run in the family?

Currently, doctors and scientists are unsure exactly what causes coeliac disease, but they think there are links to our genetics and possibly our environment.

If you have a close family member with coeliac disease (a parent or brother or sister), you have around a 10% higher risk of having the condition yourself.

It’s recommended that family members get tested for coeliac disease if a family member is diagnosed.

Coeliac disease can be triggered by feeding babies foods containing gluten before they are six months old. This is also the recommended age for weaning babies onto any solid food.

There is also a small risk that babies can develop the condition if they’re not being fed breast milk when they do start to consume gluten.

How is coeliac disease treated?

Coeliac disease cannot be cured, but it can be managed. At the moment, the only and best way to manage coeliac disease is to avoid all foods and drinks containing gluten.

Completely eliminating gluten from your diet will allow your gut to recover. By not eating gluten, your immune system will no longer be producing antibodies to gluten.

If you get your condition under control and have a blood test to check for gliadin antibodies, it will come back negative. This does not mean that your condition has gone away. It simply means it’s under control and being managed.

If you start eating gluten again, the antibodies, and your symptoms, will return.

If you have been diagnosed with coeliac disease, it is essential to see a dietician. A dietician can advise you on your diet and address any deficiencies that might be present, such as your calcium or vitamin D intake, provide you with guidance on interpreting food labels and give you advice on how to manage your diet when eating out or when traveling to other countries.

A dietician can also help you to ensure that you are reaching all of your nutritional requirements when gluten has been removed from your diet.

What about the new coeliac disease vaccine?

Researchers are exploring the possibility of a vaccine that could change the lives of coeliac disease sufferers.

While testing of a vaccine called NexVax2 has been discontinued, extensive research continues with various potential therapies in development.

Can I eat small amounts of gluten?

It’s a common mistake that people think that consuming small amounts of gluten is ok for someone with coeliac disease. But this simply isn’t true.

Tiny amounts of gluten can send the immune system into overdrive and send antibodies to gliadin on the attack. Continually eating gluten can cause serious health problems later in life.

Can I grow out of coeliac disease?

Having coeliac disease is a health condition that will stay with you for life. Reintroducing gluten back into your diet at any time will trigger symptoms meaning that the lining of the small intestine can become damaged again.

What is refractory or unresponsive coeliac disease?

Sometimes, even eliminating all gluten from the diet doesn’t relieve the symptoms of coeliac disease. It results in severe and continuous diarrhoea and pain, and rapid weight loss. This is known as refractory, or unresponsive, coeliac disease and is very rare.

It’s more common in people over the age of 50 and affects around 2-5% of people with coeliac disease.

In some cases, refractory coeliac disease requires treatment with immune suppressing drugs or steroids.

If I leave coeliac disease undiagnosed or untreated, what will happen?

At the moment, the best way to prevent triggering flare-ups of coeliac disease is to completely avoid foods containing gluten.

If coeliac disease is left undiagnosed or untreated, or someone with the condition regularly eats foods containing gluten, it can lead to further complications.

These complications are related to long term malabsorption of certain nutrients such as folate, vitamin B12, vitamin D, calcium and iron. This can lead to the sufferer becoming malnourished, which itself can lead to:

• Constant tiredness
• Weakness
• Dizziness or feeling faint
• Difficulty staying balanced
• Confusion and ‘brain fog’
• Tingling in your hands and feet
• Swelling of the arms, hands, legs and feet
• Struggling to recover from illnesses, infections, bruising and wounds
• Muscle wastage
• Difficulty keeping warm
• Infertility

Other complications include:

• Folate deficiency anaemia
• Vitamin B12 deficiency anaemia
• Brittle bone disease (osteoporosis)
• Iron deficiency anaemia

Bowel cancer, although rare, can also be caused by poorly managed coeliac disease. In women, it can also lead to low birth weight babies.

What are the long term prospects of having coeliac disease?

Researchers have noticed that people with certain other medical conditions have a higher chance of also having coeliac disease.

These include:

• Ulcerative colitis, a type of inflammatory bowel disease that affects the large bowel
• Type 1 diabetes
• Epilepsy and other conditions that affect the brain and/or nervous system
• Conditions that affect the thyroid

As yet, researchers are unsure whether having these conditions places someone at a higher risk of developing coeliac disease, or whether the conditions and coeliac disease have the same cause.

Having coeliac disease also puts you more at risk of developing an intolerance to lactose, the sugar that naturally occurs in cow’s milk and dairy products.

A lactose intolerance causes bloating, excess wind, abdominal pain and diarrhoea. Although the symptoms are similar to having coeliac disease, eating or drinking foods that contain lactose won’t mean that your immune system attacks your gut.

Avoiding cow’s milk and dairy products such as cheese, butter and yoghurts will help to reduce your gastrointestinal symptoms if you have a lactose intolerance.

More information

• If you have the symptoms of coeliac disease or you think you might have the condition, speak to your GP as a first line of investigation. They may refer you to a specialist doctor called a gastroenterologist for more tests.
• If you don’t currently have a GP, you can make an appointment with one of our same day private GPs.
• At King Edward VII’s Hospital, we also have specialist departments that can help with diagnosing and treating the symptoms of coeliac disease including our dedicated Gastroenterology, Endoscopy and Dermatology