Mouth ulcers, peripheral arthritis, and eye inflammation are all possible extraintestinal symptoms of Crohn’s disease — disease-related effects occurring outside the gastrointestinal (GI) system.

Crohn’s disease is one type of inflammatory bowel disease (IBD). It is a lifelong condition that causes inflammation in the GI system that can be progressive, affecting any part of the GI tract from the mouth to the anus.

As a GI condition, Crohn’s disease classically presents with a variety of gastrointestinal symptoms, such as diarrhea, rectal bleeding, and bowel urgency.

However, an estimated 25–40% of people living with IBD also experience symptoms outside of the GI tract. These extraintestinal symptoms, known formally as extraintestinal manifestations (EIMs), affect tissues throughout the body.

This article looks at extraintestinal symptoms of Crohn’s disease and ways to manage them.

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Medical illustration by Bailey Mariner

Joint pain, known as arthralgia, and joint inflammation, known as arthritis, are common EIMs.

According to a 2021 review in the journal Gastroenterology, they affect approximately 46% of people living with IBD but appear to decrease with age.

Common types of arthritis and joint pain in Crohn’s disease include:

  • Peripheral arthritis: Joint inflammation in the larger joints of the body.
  • Axial arthritis: Arthritis affecting the lower back.
  • Ankylosing spondylitis: Inflammation in the joints and ligaments of the spine.
  • Enthesitis: Inflammation of the junction where connective tissue inserts into bone.

Musculoskeletal conditions such as arthritis can be treated with anti-inflammatory medications, though experts recommend them with caution. Some medications may irritate the GI tract and worsen symptoms of Crohn’s disease.

Home care includes rest, application of moist heat to the joint, and range of motion exercises under the guidance of a rehabilitation specialist.

Anemia occurs when the red blood cell count in the body drops below baseline levels.

In Crohn’s disease, anemia is an EIM directly related to the GI tract’s diminished ability to absorb vital nutrients such as iron, folic acid, and vitamin B12.

Anemia affects approximately 33% of people living with IBD. It can be caused or worsened by intestinal bleeding and the use of certain medications.

Anemia does not always have obvious symptoms, but signs that red blood count may be low include:

  • pale complexion
  • chills
  • fatigue
  • headaches
  • shortness of breath
  • irregular bleeding
  • dizziness, lightheadedness, and fainting

In many cases, nutritional supplements can treat anemia. Blood transfusions and intravenous iron may be necessary in severe cases or when oral iron supplements are not well-tolerated.

Eating iron-rich foods and those that contain B12 may also help improve the extraintestinal symptom of anemia.

Oral aphthous ulcers are mouth sores that people commonly refer to as “canker sores.”

According to a 2019 systematic review in the journal Diagnostics, as many as 20% of adults and 41% of children living with IBD experience canker sores as an EIM.

Canker sores may appear anywhere on the soft tissue inside the mouth. Symptoms include:

  • small, round ulcers on the tongue, lips, or cheeks
  • ulcers that are gray, white, or yellowish
  • burning or tingling sensation in the mouth

Canker sores are not transmissible. They may be related to poor vitamin absorption due to GI inflammation.

Over-the-counter (OTC) medications can help numb the pain of mouth sores. Mouth rinses and other OTC antiseptics can also help improve healing and prevent the spread of infection.

Eating spicy or abrasive foods may aggravate EIM mouth sores.

Skin EIMs affect an estimated 15% of people living with IBD. They often present as lesions, rashes, lumps, bumps, and nodules of varying sizes on the skin.

Examples of common EIM skin conditions include:

  • Erythema nodosum: Sensitive red bumps on the extremities.
  • Pyoderma gangrenosum: Blisters that progress to ulcers on the arms and legs.
  • Sweet syndrome: Tender skin lesions primarily on the upper body accompanied by fever.
  • Skin tags: Small flaps of skin growth.
  • Enterocutaneous fistulas: Pus- or fecal-filled tracts that form between the skin and the intestine.
  • Anal fissures: Small tears in the tissue of the anal canal.
  • Acrodermatitis enteropathica: Flaky rash on the hands, feet, face, and perineum.

In most extraintestinal skin symptoms, treating IBD is the treatment for the EIM.

Some conditions, such as acrodermatitis enteropathica, can improve with proper nutrition, which decreases the risk for nutrient deficiencies.

EIMs can also affect the internal organ function of the liver and kidneys. Serious liver disease is an EIM affecting an estimated 5% of people living with IBD.

Liver complications can include:

  • Hepatitis: Liver inflammation.
  • Gallstones: Pebble-like buildup in the gallbladder.
  • Fatty liver disease: Buildup of fat deposits that lead to scarring.
  • Primary sclerosing cholangitis (PSC): Bile duct inflammation.

Of these, a 2021 review in the World Journal of Hepatology indicates PSC is the most common, affecting up to 8% of people living with IBD. PSC is a condition where the bile ducts of the liver become inflamed, eventually narrowing from damage and scarring.

Kidney EIMs are rare but include:

  • Kidney stones: Accumulations of crystals in the kidney.
  • Fistulas: Abnormal tracts between the intestines and other organs.
  • Amyloidosis: Abnormal protein deposits in organ tissue.
  • Glomerulonephritis: Kidney lesions that affect filtration.
  • Hydronephrosis: Obstruction of the ureter.

Medications to treat IBD can cause kidney dysfunction in a very small percentage of people.

When detected early, liver and kidney EIMs are often reversible in a medical setting.

Crohn’s disease can affect more than just the areas mentioned above. It can also cause EIMs that affect the:

  • eyes
  • vascular system
  • lungs
  • mental health

For example, a 2021 clinical trial in the journal Scientific Reports found symptoms of anxiety and depression were present in approximately 33% of participants living with IBD.

Extraintestinal symptoms of Crohn’s disease can affect multiple organ systems beyond the GI tract.

They are common in the skin, joints, and mouth. Extraintestinal symptoms of Crohn’s disease are associated with greater morbidity and lower quality of life in IBD.

While medications, exercises, diet, and supplements may all help improve EIMs, long-term relief comes through the management of Crohn’s disease itself.