How Is Inflammatory Bowel Disease Linked To Psoriasis?
Reviewed by: HU Medical Review Board | Last reviewed: July 2016.
Inflammatory bowel disease (IBD) is the name for a set of conditions in which chronic inflammation inside of the digestive tract can cause many different symptoms, including abdominal pain, diarrhea, and cramping1. The most common forms of IBD are called ulcerative colitis and Crohn’s disease.
Like psoriasis, IBD is a chronic inflammatory condition. Symptoms may get better or even disappear for longer periods of time, but the condition is not curable and symptoms return or flare-up over time.
How common is IBD among people with psoriasis?
Studies suggest that people with psoriasis have a higher risk of developing IBD during their lifetimes3. Statistically, the two conditions occur more often in people who have been studied than they would if the two diseases were not somehow related. For example, one recent study found that 1 in 10 women with psoriasis had developed an IBD4. Research also suggests that people who have both psoriasis and psoriatic arthritis had an even higher risk of inflammatory bowel disease than people who have psoriasis but no psoriatic arthritis diagnosis5.
How is IBD linked to plaque psoriasis?
Psoriasis and IBD are both conditions with symptoms that are caused by inflammation that is due to an overreaction of the immune system3. Researchers believe that there is a genetic link between the two conditions—that certain families carry specific genes that affect the immune system’s functioning and make members of those families more likely to develop both conditions5.
What are the causes and symptoms of IBD?
The exact causes of IBD are still unknown. However, researchers think that they are probably caused by a combination of genetics, the environment, and microorganisms in the gut (viruses, fungi, bacteria, or yeasts). The current theory is that these diseases develop when a person’s immune system has the genetic tendency to overreact to harmless microorganisms in the gut1. This reaction causes chronic inflammation anywhere along the digestive tract. The differences between Crohn’s disease and ulcerative colitis have to do with the location and severity of the symptoms2.
Ulcerative colitis symptoms
Ulcerative colitis mainly affects the lining of the colon (the large intestine) and the rectum. Inflammation cause swelling and sores called ulcers to develop in those areas of the digestive tract. Ulcerative colitis can cause symptoms including:
- Abdominal pain and cramping
- Rectal bleeding
- Bloody stools or diarrhea
- Weight loss
Crohn’s disease also involves inflammation and ulcers. However, they can occur anywhere in the digestive tract, from the mouth to the anus, but most commonly affect the small and large intestines. In Crohn’s disease, the inflammation can occur much deeper into the lining of the intestines than ulcerative colitis symptoms. Common symptoms of Crohn’s disease are:
- Diarrhea and constipation
- Rectal bleeding
- Incontinence and the need to use the toilet urgently
- Abdominal cramping and pain
- Weight loss and loss of appetite
This chronic, long-term inflammation in people with Crohn’s disease can cause serious problems in the digestive tract: scarring, abscesses (areas of infection), narrowing of the intestines, and intestinal blockage.
How is IBD treated?
Neither psoriasis nor IBD has a cure, but both can be treated and many people find that they are able to manage their symptoms. The aim of treating IBD is to reduce the amount of inflammation in the person’s digestive tract, which helps to improve symptoms and prevent further damage1. For people with milder forms of IBD, anti-inflammatory medicines called aminosalicylates are often recommended.
Several of the same medications that are used to treat more severe psoriasis are also used to treat moderate or severe inflammatory bowel disease. These are powerful drugs that work by reducing the amount of inflammation in the entire body, such as:
- Systemic medicines, such as methotrexate
- Biologic therapies, such as infliximab and adalimumab
Around 75% of patients with Crohn’s disease and 25% patients with ulcerative colitis will eventually need to have surgery to treat the condition2. The type of procedure needed can vary, from surgery to widening areas of the intestine that have become too narrow to procedures to remove small or large sections of the intestine.