How Is Inflammatory Bowel Disease Linked to PsA?

People with psoriatic arthritis (PsA) show an increased risk of developing a range of gastrointestinal conditions, including inflammatory bowel diseases (IBD) like Crohn’s disease and ulcerative colitis. People with PsA are also at greater risk of developing celiac disease, autoimmune hepatitis, and non-alcoholic fatty liver disease.¹

Both PsA and IBD are associated with an abnormal immune response, causing inflammation in the body. The inflammation is most noticeable in the joints of people with PsA, but it can be anywhere the body. This is called systemic inflammation, and it may increase the risk of having IBD. In addition, IBD and PsA share similar genetic mutations.^2,3

What is Crohn’s disease?

Crohn’s disease causes inflammation of the digestive system, affecting areas from the mouth to the anus. It often affects the lower part of the small intestine, the ileum. The cause of Crohn’s disease is unknown, but it does run in some families. Crohn’s disease can cause issues such as:⁴

• Bleeding from the rectum
• Weight loss
• Fever
• Intestinal blockages
• Ulcers in the intestines
• Malnourishment

There is no cure for Crohn’s disease. Treatment can help manage symptoms, and the disease can include periods of remission.⁴

What is ulcerative colitis?

Ulcerative colitis causes inflammation and ulcers in the lining of the rectum and colon. It can occur at any age but most often begins between the ages of 15 and 30. Ulcerative colitis tends to run in families, which suggests it may be inherited through genes. The most common symptoms are abdominal pain and blood or pus in diarrhea. Severe cases may require surgery to remove the colon. Treatment can help control symptoms, and some people experience long periods of remission.⁵

What is celiac disease?

Celiac disease is also known as gluten intolerance. When people with celiac disease eat gluten, their immune system attacks the small intestine and damages it. Gluten is a protein found in wheat, rye, and barley. Celiac disease is inherited. The most common symptoms are:⁶

• Abdominal pain
• Diarrhea
• Irritability
• Depression

What is autoimmune hepatitis?

In autoimmune hepatitis, the body’s immune system mistakenly attacks the liver, causing inflammation and liver damage. Common symptoms include:⁷

• Feeling tired
• Joint pain
• Nausea
• Poor appetite
• Jaundice
• Pain in the upper abdomen

What is non-alcoholic fatty liver disease?

Non-alcoholic fatty liver disease is a type of liver damage that is not related to drinking alcohol. It causes inflammation in the liver, which causes scarring of the liver. This scarring may lead to cirrhosis or liver cancer. There are few symptoms other than feeling tired or uncomfortable in the upper right side of the abdomen. There are no drugs approved to treat non-alcoholic fatty liver disease.⁸

Can treatment reduce risk?

Treatment of gastrointestinal disease and PsA is important to reduce the risk of long-term complications and improve quality of life. In PsA, treatment can slow or prevent potential joint damage, deformity, and disability. In IBD, treatment can induce and maintain remission, improving quality of life and helping avoid the risk of surgery and long-term complications.^2,9

Do some treatments for PsA and GI conditions overlap?

There is not much data on how to best treat a person who has both PsA and gastrointestinal conditions. However, some of the same drugs are used to treat both PsA, IBD, and autoimmune hepatitis, including:^2,9

• Steroids
• Biologics such as infliximab (Remicade®), adalimumab (Humira®), ustekinumab (Stelara®), and certolizumab pegol (Cimzia®)
• Azathioprine (Imuran®)

There are no clear guidelines to determine an appropriate treatment for people with both IBD and PsA. In addition, no guidelines exist regarding the use of non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen in people with PsA and IBD, since it is unclear whether NSAIDs may make IBD symptoms worse.⁹

Celiac disease is treated by eliminating all gluten from the diet. Some symptoms of IBD, autoimmune hepatitis, and non-alcoholic fatty liver disease may improve with changes in diet.^4-7