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Ulcerative Colitis and Skin Conditions: Understanding the Connection

Due to the systemic nature of inflammation in ulcerative colitis (UC), the condition can affect more than just your gastrointestinal system. These symptoms are known as extraintestinal manifestations (EIMs). Up to 50% of patients experience EIMs, with skin conditions being among the two most common, together with joint manifestations. 

Here you can find the latest research and insights on UC and skin conditions, as well as recommended treatments according to IBD experts. 

The Connection Between UC & Skin Conditions 

Studies show a bidirectional relationship between the gut microbiome and skin health. This is known as the Gut-Skin Axis, in which the gut microbiome and the skin immune system communicate and interact.

However, disruptions in the gut microbiome can influence how the skin’s immune system reacts and vice versa. When factors like antibiotics, stress, or diet disturb gut homeostasis (balance), an immune response is activated, causing inflammation. This inflammation is later observed in the skin as symptoms like rashes and itching. 

The Gut-Skin Axis is also observed in food allergies. In this case, the immune system mistakenly identifies certain food proteins as harmful and releases inflammatory mediators, leading to allergic reactions that can include symptoms such as rashes and vomiting.

How do I know if my skin symptoms are caused by IBD?

According to Professor Shomron Ben-Horin, Chief of Gastroenterology at Sheba Hospital, patients with IBD may mistakenly confuse an ordinary rash with an EIM. Ben-Horin explains that most – although not all – skin EIMs typically accompany an IBD flare-up, and persist for more than several days to weeks. If a transient short-lived skin rash or itching occurs for a couple of days and subsides, it is very unlikely to be related to underlying IBD. 

Skin conditions that can be observed in EIMs of IBD: 

Erythema Nodosum involves red, raised pustules that are painful rather than itchy and are experienced by 5-10% of patients at some time during the course of their disease. It often appears on the shins. Over 80% of patients respond well to corticosteroids or TNF inhibitors (Anti-TNFs); however, in patients who do not improve with the traditional treatment, alternative treatments may improve response rates. 

Pyoderma Gangernosum causes ulcerated wounds that are more severe than erythema but fortunately affect less than <1% of patients. This more serious condition can affect any part of the body and can appear following local trauma but usually does not appear concurrent with a disease flare. It can start as a small wound-like lesion and expand to become an ulcer-like lesion in the skin that’s a few centimeters. According to Ben-Horin, patients with Pyoderma Gangernosum need urgent care and usually respond well to corticosteroids, anti-TNF, or Cyclosporine.

Vasculitis is a rare allergic immuno-reaction that is not considered an EIM, but rather a rare complication of viral infections or a rare side effect of IBD medications. However, IBD patients also have a slightly higher rate of concomitant vasculitis (also possibly an auto-immune disorder). It may manifest on the skin as red-purplish lesions of varying size and are usually not painful. This inflammation of blood vessels can develop into a more serious condition if left untreated, so patients who experience this should promptly see their doctor or go to their local emergency room. Corticosteroids have a high success rate in treating vasculitis.

When Should I Seek Medical Advice?

If you have IBD and notice pustules or ulcers on your skin, you may be experiencing EIMs—especially if they appear during a flare-up of your IBD symptoms. 

Not all rashes are caused by IBD, and it is best to consult with your general practitioner or a dermatologist to address it if it does not go away in 1-3 days. 






This blog is not intended to provide diagnosis, treatment, or medical advice. The content provided is for informational purposes only. Please consult with a physician or healthcare professional regarding any medical or health related diagnosis or treatment options. The claims made regarding specific products in this blog are not approved to diagnose, treat, cure, or prevent disease.


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Reviewed by Prof. Shomron Ben-Horin M.D.

Co-founder & Chief Medical Officer of Evinature, Chief of the Gastroenterology Department & Director of the Gastro-Immunology Research Laboratory at Sheba Medical Center.

Currently a professor of Medicine at Tel Aviv University, Ben-Horin has been the President of the Israel IBD Society, a member of the Scientific Committee of the European Crohn’s & Colitis Organization (ECCO), and an Associate Editor of the Journal of Crohn & Colitis. He is currently a member of the prestigious International Organization of IBD (IOIBD), and a member of the Editorial Board of leading journals, Gut, JCC, and APT.


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