If you’ve got long-term diarrhea and tummy pain, you may have Crohn’s or celiac disease. While both diseases have similar signs and symptoms, their treatments are different, which is why it’s important to distinguish between the two.

This article will give you the answer to your question — is it Crohn’s or celiac?

Crohn’s vs Celiac — Who Gets It?

Each disease is more common in certain populations, and your race and location can increase your risk of developing one or the other. 

This is called epidemiology of a disease and doctors often use patients’ demographic data to narrow down their diagnoses.

Compared to Crohn’s, celiac is rare in the US. Every 200 in 100,000 individuals may be suffering from Crohn’s but only 1 in 150 will have celiac disease. 

Then, individuals of Northern European and Ashkenazi Jewish descent have a higher prevalence of Crohn’s disease, so if you belong to either group, your chances of developing Crohn’s are higher. But note that northern Europeans have a higher prevalence of celiac disease too.

Genetic factors have also been associated with both Crohn’s and celiac. And while a family history of either disease doesn’t help differentiate between the two, it does help in differentiating between these two and other GI diseases. 

Finally, people who use tobacco (actively or passively) are more likely to develop Crohn’s than celiac disease, so cigarette smoking is an important clue when you’re trying to differentiate between the two.

Why do Crohn’s and celiac disease occur?

Both Crohn’s and celiac disease occur because the body attacks itself — both are autoimmune diseases. But why the body attacks itself is different for each disease.

Celiac disease

In celiac disease, our immune system gets triggered by a molecule called gliadin. Gliadin is a component of a bigger molecule called gluten, which is found in grains like wheat, rye, and barley as well as foods derived from these.

When you eat these foods, the immune system gets charged up but misfires, attacking your intestines instead of gluten. This leads to inflammation in the small intestines, resulting in long-term diarrhea, pain, nausea, and vomiting.

Crohn’s disease

Unlike celiac disease, doctors don’t really know what causes immune system activation in Crohn’s disease.

But just like celiac disease, the body attacks the small intestine (and sometimes the large intestine), which leads to chronic diarrhea, abdominal pain, and vitamin malabsorption.

While celiac disease remains limited to the small intestine, Crohn’s can involve any part of the GI tract from the mouth to the anus. However, Crohn’s usually affects the terminal small intestine, which is why patients may complain of pain in the right lower quadrant of their tummy. 

So if you’ve been experiencing pain in that part of the abdomen over a period of months, you may have Crohn’s.

How to differentiate between symptoms of Crohn’s and celiac disease? 

Extraintestinal symptoms of both the diseases differ considerably, which makes them more useful than gastrointestinal (GI) symptoms in differentiating between the two. 

GI symptoms

GI symptoms of both Crohn’s and celiac are more or less the same. Nonetheless, important differences occur and can be valuable clues during a work-up.

Because celiac disease is triggered by gliadin, it may get worse when you consume a gliadin-rich diet (wheat, rye, barley, beer etc.) and improve when you let go of it. This is not seen with Crohn’s and is an important differentiating feature.

Another important difference is related to fistulas and abscesses. Fistulas are abnormal connections between two structures. In Crohn’s, a fistula may develop between your small intestine and the skin around your anus. This is called a perianal fistula and is often the first sign of Crohn’s disease.

A fistula will present as an ulcer (or a wound) around your anal area and may have a discharge. Fistulas are not seen with celiac disease, so their absence makes it highly likely that you have celiac instead of Crohn’s.

Finally, since Crohn’s disease can affect any part of the GI tract, it often presents with oral aphthous ulcers (unlike celiac). Aphthous ulcers — also known as canker sores — are round in shape and have a gray center with a reddish surrounding. They usually occur in the soft areas of the mouth like inside of the lips, cheeks, and under the tongue.

Extraintestinal symptoms 

Extraintestinal symptoms occur in areas outside the GI tract (like the eyes and joints) and are different for Crohn’s and celiac disease.

Skin symptoms are the most useful in differentiating between the two. Crohn’s is associated with a skin condition called pyoderma gangrenosum, which often manifests as quickly-developing, painful red spots on the thigh and shin. These can turn into ulcers and may require steroids to control.

While pyoderma gangrenosum is not unique to Crohn’s disease (it can happen in rheumatoid arthritis, for example), it’s certainly not associated with celiac, which makes it an important differentiating feature.

Joints are another important area that can help differentiate between celiac and Crohn’s. Joints are usually not affected in celiac disease but can be affected by a condition called enteropathic arthritis in patients with Crohn’s.

Symptoms of enteropathic arthritis include lower back pain that improves with exercise as well as pain at sites where tendons insert into the bone (such as the heel). So if you’ve got painful joints in addition to tummy symptoms, your doctor will be inclined towards Crohn’s disease.

Finally, eye symptoms are another useful set of extraintestinal symptoms to differentiate between the two diseases.

While a range of eye problems can be seen in Crohn’s disease, patients with celiac disease are usually free from eye symptoms. Eye problems that can be seen in Crohn’s disease include inflammation of the iris, the membrane lining the white of the eye, as well as the ciliary muscle and the retina.

So unlike celiac, if you’ve got Crohn’s disease, you can have a wide range of eye symptoms depending upon which part of the eye is inflamed.

Crohn’s vs Celiac — A Quick Summary 

Both Crohn’s and celiac disease are autoimmune conditions that mainly affect the small intestine, resulting in symptoms like diarrhea, abdominal pain, nausea, and vomiting.

Doctors know that gliadin is the molecule responsible for celiac disease but such a molecule has not been identified for Crohn’s yet.

While the GI symptoms of both diseases are similar, extraintestinal symptoms (such as those affecting the eye, skin, and the joints) will give you helpful clues when you’re trying to determine the cause of your tummy symptoms! 

Medically Reviewed by Onikepe Adegbola, MD PhD