Crohn’s disease is an inflammatory bowel disease (IBD) that causes inflammation in the gastrointestinal tract. Common symptoms include stomach pain and diarrhea.

Crohn’s disease can also impact other parts of the body, including the skin. Experts estimate that almost a third of people with Crohn’s disease experience skin complications, such as skin rashes.

Crohn’s disease may lead to skin rashes that can occur on virtually any part of the body. There are different types of skin rashes you may develop:

Erythema Nodosum

Erythema nodosum is one of the most common skin rashes associated with Crohn’s disease. The rash is believed to impact up to 15% of people who have Crohn’s, and it’s seen more often in women than in men.

Appearance: Erythema nodosum typically appears as a rash of multiple red or darker-than-skin-color nodules (bumps on the skin) on the shin area. It’s often described as feeling tender or painful and sometimes warm to the touch.

Development: This rash tends to develop during Crohn’s flare-ups (when the disease produces active symptoms). It might also occur with other symptoms like fever, chills, and joint pain.

Treatment: Erythema nodosum can usually be managed with treatment tactics like leg elevation, rest, compression socks, and pain management. More severe cases could require a course of corticosteroids to reduce inflammation.

Pyoderma Gangrenosum

Pyoderma gangrenosum is another common skin rash linked to Crohn’s disease. It’s estimated that 20-50% of people with pyoderma gangrenosum also have Crohn’s or another type of IBD.

Appearance: This painful skin issue usually starts as small blisters or raised bumps on the skin that develop into deep ulcers (sores). In adults, it’s commonly located on the lower half of the body, such as the legs. In children, pyoderma gangrenosum is more likely to develop on the head or around the genital area.

Development: Pyoderma gangrenosum can be triggered by a minor trauma to the skin (e.g., bumping or bruising your leg) and may not necessarily correspond with a Crohn’s flare-up.

Treatment: Most cases need topical treatment to prevent infection and support healing, though more severe or stubborn cases might require oral or injectable medications. Once treated, pyoderma gangrenosum often leaves behind significant scarring.

Sweet Syndrome

Sweet syndrome is relatively rare. When it does occur, it more often affects women.

Appearance: The rash can appear as tender red or discolored bumps and blisters. It’s generally found on parts of the upper body, like the face and neck.

Development: It commonly develops during a Crohn’s flare-up. Along with the rash, you may develop a sudden fever and joint or muscle pain. You might also have a high white blood cell count.

Treatment: Most sweet syndrome rashes can be treated within a few months using oral or topical corticosteroids. The rash may reoccur later.

Acrodermatitis Enteropathica

Acrodermatitis enteropathica is a rash caused by a zinc deficiency. This type of mineral deficiency is common among people with Crohn’s because of the amount lost from chronic (long-term) diarrhea.

Appearance: This dry, flaky rash usually develops on the face, hands, feet, and anal area. It can be described as patchy and may contain pustules (pus-filled bumps).

Development: Acrodermatitis enteropathica can become noticeable when you have a zinc deficiency.

Treatment: The rash generally resolves itself with zinc supplementation or when Crohn’s symptoms like diarrhea improve.

Other Skin Rashes

There are several other Crohn’s-related skin rashes that aren’t quite as common. Here are a few of them:

• Pyoderma vegetans: Because IBD triggers an overactive immune system response in the body, people with Crohn’s may be more likely to develop this type of skin rash. It often shows as a raised, blistery, patchy rash in areas where the skin folds together, like the groin or armpits.
• Vasculitis rash: Vasculitis is a condition that causes blood vessels underneath the skin to swell. It may develop due to abnormal immune system activity, a signature part of Crohn’s disease. Vasculitis can trigger a raised, red or purple-colored rash that may come with skin ulcers.
• Epidermolysis bullosa acquista: This blistery rash is usually found in people who’ve had Crohn’s disease for several years. Large blisters filled with fluid develop on the hands, feet, knees, and elbows. Because it’s fairly rare, experts are still studying its connection to Crohn’s—though inflammation and immune system overactivity seem to play a role.

Researchers are still studying the relationship between IBD and the skin. Initial evidence around why Crohn’s disease may trigger skin-related symptoms has found that the following factors may cause skin rashes in Crohn’s:

• Disease activity: Some skin rashes have similar features to Crohn’s disease when the affected skin cells are examined under a microscope, suggesting the rashes might directly result from the digestive disorder. Other skin issues appear to be triggered mostly by inflammation from a Crohn’s disease flare-up.
• Malnutrition: Crohn’s disease causes digestive tract inflammation, making it more difficult for the body to absorb essential nutrients and vitamins. When your body doesn’t absorb enough nutrients, you may be more likely to develop a skin rash or condition.
• Medication: Certain Crohn’s medications, like biologics, have the potential to prompt skin-related side effects.
• Genetics: Some initial studies suggest there may be a genetic factor that makes it more likely for a person with Crohn’s disease to experience skin issues from the condition.

If you have a skin rash due to Crohn’s disease, you may have to address both the rash and the Crohn’s itself. The exact treatment will depend on the type of rash and its specific cause. In many cases, treatment includes medications such as:

• Corticosteroids: Medications like Deltasone (prednisone) are useful for calming skin inflammation and managing Crohn’s flare-ups. Different corticosteroids can be taken by mouth, injected into the affected skin area, or applied directly to the skin.
• Immunosuppressants: This class of drugs, including options like Imuran (azathioprine), are used in oral or injectable format to keep Crohn’s symptoms under control.
• Anti-inflammatory medications: Options like Azulfidine (sulfasalazine) can help clear certain skin infections and reduce related inflammation.
• Biologics: Medications such as Humira (adalimumab) target the immune system to reduce the widespread inflammation Crohn’s causes.

Other treatment options include topical wound care, zinc supplementation, stopping a biologic if it’s contributing to the skin issue, or surgery in severe cases to remove a skin lesion.

Crohn’s disease is a chronic condition that goes through periods when symptoms are happening and periods when there are few or no symptoms. Because of the unstable nature of the disease, it’s good to keep in regular touch with your healthcare provider.

You should especially consider contacting your provider if symptoms worsen or occur more often and if you begin to experience skin abnormalities.

See a healthcare provider right away if you have Crohn’s and notice a skin rash that:

• Covers a large part of your body
• Starts to spread
• Causes pain or discomfort
• Blisters or turns into open sores
• Comes with signs of infection, like a fever, pus, or a foul smell

In addition to digestive symptoms, various skin rashes can be a symptom of Crohn’s disease. Crohn’s flare-ups often trigger skin rashes, which may develop in different areas and vary in appearance.

Crohn’s disease skin rashes can usually be managed with medications and other treatment strategies. Contact a healthcare provider if you have Crohn’s and have noticed any skin changes.