Psoriatic arthritis and Crohn's disease: Links and more

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The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) describes PsA as a progressive inflammatory condition of the joints and entheses — the places where tendons and ligaments attach to the bones.

PsA can affect people of any age, including children. However, it often develops between the ages of 30 and 50.

Most people who get PsA already have psoriasis as an underlying condition. The National Psoriasis Foundation says in many people, PsA develops 10 years after psoriasis. However, a person can develop PsA before psoriasis.

The symptoms of PsA include:

• scaly, inflamed patches of skin
• joint pain
• tenderness near the ligaments, especially on the back of the heel and soles of the feet
• painful swelling of fingers or toes
• eye inflammation (uveitis)
• nail deterioration, including crumbling and separation

The National Psoriasis Foundation adds fatigue, reduced range of motion, and stiffness in the morning to this list.

PsA can also significantly affect an individual’s mental health, especially in severe cases. Pain in the joints, a reduced range of motion, and deformations can lower a person’s self-esteem.

Types of psoriatic arthritis

According to an older 2014 article, PsA has five categories:

• Distal interphalangeal predominant: This type affects the ends of the fingers and toes, where the distal interphalangeal joints are. A person is likely to experience nail changes in this form of PsA.
• Asymmetric oligoarticular: This is one of the most common forms of PsA. It affects different joints on either side of the body.
• Symmetric polyarthritis: Another of the most common forms of PsA. It affects the same joints on each side of the body.
• Spondylitis: When PsA involves inflammation in the joint between the spinal vertebrae. A person with spondylitis can experience neck and back pain. The joints in the arms, legs, hands, and feet may also be painful.
• Arthritis mutilans: This type of PsA is the least common but most severe. It causes severe inflammation in the joints of the hands and feet, affecting a person’s movement and causing deformation. Fewer than 5 in 100 people with PsA have arthritis mutilans.

A 2022 overview of the condition notes that people with PsA also have a higher risk of death from cardiovascular diseases in comparison with the general population.

There is currently no cure for PsA.

Learn more about the effects of psoriatic arthritis here.

Diagnosis

It is important that a person gets an early diagnosis of psoriatic arthritis. This can help them manage the condition more effectively and reduce the risk of long-term disability.

However, there is no specific test to diagnose psoriatic arthritis. A person may see different health professionals for a diagnosis depending on the symptoms they develop first. For instance, a person may see a dermatologist if they experience nail changes before they develop arthritis pain.

A doctor can use the person’s medical history, physical examinations, blood tests, X-rays, and MRI scans to diagnose PsA.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Crohn’s disease is a chronic disease that causes inflammation and irritation in the digestive system. Its symptoms include diarrhea, abdominal cramps and pains, and weight loss.

It is a form of inflammatory bowel disease (IBD), and recent research suggests that people with PsA have a higher risk of also developing IBD. Therefore, there may be a link between these conditions.

The same article reports that a person’s genes play a role in PsA. This means that a genetic predisposition increases the risk of developing IBD and, in turn, Crohn’s disease among individuals with PsA.

Scientists do not yet understand what causes PsA or Crohn’s disease. However, some factors can contribute to the risk of developing either disease.

The risk factors that may contribute to PsA and Crohn’s disease include having a family history of either condition and autoimmune reactions.

Other contributing factors to PsA may include:

• skin inflammation, including psoriasis
• other autoimmune diseases
• nail disease
• obesity
• trauma
• stress
• infection
• diarrhea
• environmental factors, such as injuries from heavy lifting

However, studies of these risk factors often produce conflicting results. As a result, more research is needed on many of these risk factors to determine how much they contribute to a person’s risk of PsA.

For Crohn’s disease, other risk factors include:

• smoking
• nonsteroidal anti-inflammatory drugs (NSAIDs)
• a high-fat diet

According to the NIDDK, stress does not cause Crohn’s disease, but it can make symptoms worse.

Although there is no cure for psoriatic arthritis or Crohn’s disease, some medical treatments can be suitable for either condition.

The aim of treatment for Crohn’s disease is to reduce a person’s symptoms and stop them from reoccurring.

In PsA, treatment aims to reduce symptoms affecting the skin and joints, reduce pain and inflammation, and stop the condition from getting worse.

Medications that can reduce symptoms of both conditions include:

• aminosalicylates, which control inflammation
• corticosteroids, which reduce immune system activity
• immunomodulators, which change the activity of a person’s immune system
• biological therapies that target proteins from the immune system

The Food and Drug Administration (FDA) lists the drug adalimumab (Humira) as a treatment for both PsA and Crohn’s disease. Doctors can also use infliximab (Remicade). According to a 2019 report, people have been using Remicade for more than 20 years.

Both of these medications are tumor necrosis factor (TNF) blockers. These drugs bind to the TNF protein in the body and stop it from triggering an inflammatory reaction.

In some cases, combining two treatments can improve the symptoms of Crohn’s disease.

For instance, a 2020 study looked at participants who had gone through several unsuccessful treatments for Crohn’s disease.

Researchers combined biological therapies, including infliximab and adalimumab, and found that dual biological therapy with these drugs could lead to improvement in people with refractory Crohn’s disease. However, the authors note that more research is necessary to draw definitive conclusions.

Additionally, some biological therapy has been found to increase the risk of infection.

Surgery

The NIDDK write that nearly 60% of people had surgery within 20 years of developing Crohn’s disease. Doctors use surgery to treat the complications of the disease and reduce a person’s symptoms.

Surgery can treat:

• fistulas
• life threatening bleeding
• obstructions in the intestines
• drug side effects
• symptoms that do not improve with medication

The types of surgery a doctor may perform can include:

• Small bowel resection: This surgery involves removing part of the small intestine. A doctor may opt for laparoscopic surgery or open surgery. Laproscopic surgery, also called keyhole surgery, involves making small incisions and using a tiny camera to see inside the body to perform the surgery. In open surgery, a doctor makes a larger incision and removes the affected section of the small intestine. Learn more about bowel resection for Crohn’s disease.
• Large bowel resection: This surgery is also called subtotal colectomy. A doctor will remove a part of the large intestine either by laparoscopic or open surgery.
• Proctocolectomy and ileostomy: During a proctocolectomy, a doctor removes the entire colon and rectum. They will then need to perform an ileostomy, during which a doctor will make an opening in the abdomen, called a stoma, and attaches the ileum — the last part of the small intestine — to the opening. As stool will no longer pass through the anus, a person will then need to use a colostomy bag to collect stool passing through the stoma.

People can try several lifestyle or dietary changes to reduce their symptoms of PsA or Crohn’s disease.

NIAMS states that those with or at risk of developing PsA should:

• make a plan to quit smoking if they do smoke
• maintain a healthy weight
• explore low-impact exercises that do not strain the joints, such as yoga and tai chi
• protect affected joints by adapting common movements
• reach out to counseling or support groups

Learn more about how to quit smoking here.

Similarly, the NIDDK says those with Crohn’s disease can make changes to their diet to reduce their symptoms. This can include:

• avoiding carbonated drinks
• avoiding high-fiber foods
• drinking more liquids
• keeping a food diary to identify problematic foods

It also notes that doctors treat Crohn’s disease with medicine, bowel rest, and surgery. However, a treatment that works for one person may not work for another, so it is important for a person to work with a doctor to find the right treatment for them.

People should also speak with their doctor to determine how they can best manage their condition. If a person intends to change their diet, they should consult a doctor before making the changes to ensure the diet is balanced.

There is currently no cure for PsA or Crohn’s disease. However, a person can manage their condition day-to-day with lifestyle and dietary changes, medication, or appropriate surgery.

Both PsA and Crohn’s disease can be disruptive, and a person can experience difficult and painful symptoms. However, treatments can keep a person’s symptoms in remission, allowing them to live life as usual.

A person should make regular visits to a doctor to manage their condition and seek support for their physical and mental health.

PsA and Crohn’s disease are inflammatory conditions affecting the joints and digestive system, respectively.

There are similarities between these conditions in what risk factors contribute to a person developing them, how a person can manage them, and the medical treatments that reduce symptoms.

Individuals with either condition can lead productive lives, but it is important that they seek diagnosis and support with managing their condition early. They should work with a doctor to monitor their symptoms and get advice on the best treatment for them.