Psoriasis can affect the digestive system and lead to other issues. Research even suggests a link between psoriasis and inflammatory bowel disease.

Digestive problems such as ulcerative colitis and Crohn’s disease are common in people who also have psoriasis. However, psoriasis doesn’t directly cause these conditions.

A 2020 study broke down the prevalence of inflammatory bowel diseases (IBD) in people with psoriasis:

  • Crohn’s disease: 0.7%
  • ulcerative colitis: 0.5%

The researchers also reported that about 3.6% of people with Crohn’s disease had psoriasis, as did about 2.8% of people with ulcerative colitis.

Researchers suggest that psoriasis and inflammatory digestive diseases may develop independently of one another in some people. In other people, psoriasis may be a red flag for underlying digestive inflammation.

Experts believe that both psoriasis and IBD arise from cytokine-driven inflammation, specifically the interleukin 23 and 17 pathways.

Inflammation manifests itself through skin plaques and lesions in psoriasis. Inflammation of the digestive tract lining can also cause abdominal pain in IBD.

According to a 2022 study, 85.5% of individuals with psoriasis reported at least one gastrointestinal symptom, such as abdominal distension and constipation. This was significantly higher than individuals without psoriasis, who reported at a rate of 58.1%.

While a number of studies have shown that psoriasis and IBD share a link, how psoriasis might cause IBD isn’t clear. Overall, people with psoriasis are more likely to have other types of inflammatory conditions.

It’s difficult to get an exact number on how often people with psoriasis go on to develop IBD. However, there’s a stronger association between psoriasis and Crohn’s disease than with other inflammatory bowel conditions, such as ulcerative colitis.

There also seems to be an association between IBD and milder cases of psoriasis. A 2019 study reported that 87% of people with IBD had mild psoriasis, and 13% of people with IBD had moderate to severe psoriasis.

Unlike IBD, irritable bowel syndrome (IBS) isn’t usually linked to inflammatory disease. Instead, IBS usually appears to result from things such as:

  • intolerances to certain foods
  • bacterial infections
  • stress

Treatment for digestive problems that occur alongside or as a result of psoriasis depends on the condition.

Inflammatory conditions such as psoriasis and IBD often occur in people with similar genetic characteristics. As such, inflammatory digestive disorders may benefit from some of the same treatments as psoriasis.

Psoriasis treatments can vary based on the type and severity, but they can include things such as:

Treatment may be complicated by the fact that a number of other health problems are often found in people with psoriasis, such as:

If these conditions appear after or alongside psoriasis, you may need to treat them independently with medications or lifestyle changes, which may or may not affect your psoriasis.

Psoriasis and inflammatory bowel disorders are often linked, although their relationship outside of their shared genetic and inflammatory origins isn’t well understood.

Treatment may depend on the symptoms, but can include lifestyle changes, strict skin care, or topical and systemic medications.

Consult a doctor if you have psoriasis and experience digestive problems, or if you already have IBD and you develop skin lesions.