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What is an ulcerative colitis skin rash?

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Erythema nodosumPyoderma gangrenosumSweet’s syndromeBADASVitiligoPsoriasisPyodermatitis-pyostomatitis vegetansLeukocytoclastic vasculitisTreatment for ulcerative colitisSummary
Ulcerative colitis is a type of chronic inflammatory bowel disease (IBD). This health condition can result in several symptoms affecting the skin, including rashes.
Medically reviewed by Amanda Caldwell, MSN, APRN-C
Updated on

People with ulcerative colitis may experience symptoms outside the gastrointestinal system, including painful skin rashes. The condition can cause inflammation in the body, affecting your skin.

Skin symptoms can also be a side effect of ulcerative colitis medications. It can cause several types of skin conditions, such as:

Erythema nodosum

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Erythema nodosum is a common skin condition that can develop in people with IBD. It can cause red tender nodules in areas such as the limbs. The nodules may also turn into bruises.

The condition can be more frequent in people assigned female at birth between 25–40 years of age.

Erythema nodosum may occur during ulcerative colitis flare-ups or just before they start. It typically goes away after the flare-up is treated and managed.

Pyoderma gangrenosum

People with pyoderma gangrenosum can develop painful ulcers on their skin. They typically appear as small red bumps or blisters that turn purple while passing fluid. Some people may notice symptoms such as pus and fever if the ulcer gets infected.

The exact cause of pyoderma gangrenosum is currently unknown, but doctors think it may be related to the overactivity of the immune system. People with ulcerative colitis may have a higher risk of developing this skin condition.

A doctor may prescribe medications to treat pyoderma gangrenosum, including:

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Sweet’s syndrome

Sweet’s syndrome, also known as acute febrile neutrophilic dermatosis, is a rare disorder that may cause symptoms such as:

  • skin plaques and nodules
  • headaches
  • fever
  • oral or genital skin lesions
  • joint pain and stiffness (arthralgia)
  • eye soreness

The exact cause of Sweet’s syndrome is currently unknown. But it is thought that this skin condition may be linked to issues in the immune system.

To treat Sweet’s syndrome doctors may prescribe medications such as:

Bowel-associated dermatosis-arthritis syndrome (BADAS)

BADAS is an uncommon condition that can cause the formation of small painful bumps on your skin. This may be due to the overgrowth of bacteria in the gastrointestinal system, which can cause inflammation, similar to erythema nodosum.

Other symptoms of BADAS may include:

The treatment for BADAS typically includes taking antibiotics such as:

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Vitiligo is a skin condition that occurs when the cells responsible for producing your skin’s pigmentation die. This causes patches of white skin to develop anywhere on the body. People with IBD have a higher risk of developing vitiligo.

The most common areas of the body where vitiligo may occur include:

  • armpits
  • fingers and wrists
  • mouth
  • eyelids
  • groin
  • genitals

Treatment for vitiligo may include:

  • skin grafts
  • topical corticosteroids, such as clobetasone (Dermovate) and hydrocortisone (Cortef)
  • calcineurin inhibitors medications, such as cyclosporine (Neoral Pro) and tacrolimus (Hecoria)
  • phototherapy
  • excimer laser treatment
  • topical janus kinase (JAK) inhibitor, such as ruxolitinib (Opzelura)


Psoriasis is an autoimmune condition that causes several skin manifestations, such as scaled and red patches. A 2022 study suggests that those with psoriasis have an increased risk of going on to develop IBD.

The treatment for psoriasis can include:

  • topical creams and ointments
  • phototherapy
  • systemic treatment with oral medications and injections

Pyodermatitis-pyostomatitis vegetans

People with ulcerative colitis may develop pyodermatitis-pyostomatitis vegetans. These conditions cause red pustules (abscesses) on the skin that then turn into scaly patches.

In people with pyodermatitis, the pustules typically develop in the skin folds, such as the groin and armpits. People with this condition may also develop pustules in their mouths.

Where ulcerative colitis is the underlying cause of pyodermatitis-pyostomatitis vegetans, the first line of treatment is managing IBD symptoms.

Leukocytoclastic vasculitis

Leukocytoclastic vasculitis may be an external manifestation of ulcerative colitis.

People with leukocytoclastic vasculitis can develop symptoms such as small or large patches of purple spots on their body, commonly on their legs and ankles.

This happens when the inflammation that ulcerative colitis can cause makes small blood vessels burst.

Leukocytoclastic vasculitis typically goes away after you treat the underlying cause, such as ulcerative colitis.

Treatment options for ulcerative colitis

The treatment options for ulcerative colitis may include:

  • medications such as corticosteroids to suppress the immune system, such as:
  • medications such as immunomodulators to manage or suppress the immune system. Examples include:
    • thalidomide (Thalomid)
    • pomalidomide (Pomalyst)
  • biologic therapies to stop inflammation by using antibodies

In more severe cases of ulcerative colitis, doctors may perform surgery to remove part of the intestines and reduce inflammation. Doctors may also recommend changing your diet to prevent and manage ulcerative colitis flare-ups by avoiding certain types of food.


Ulcerative colitis is a type of IBD. The inflammation that ulcerative colitis can cause in your body can result in the development of symptoms outside the gastrointestinal system, such as skin rashes.

In most cases, the first line of treatment for the skin conditions linked to ulcerative colitis is treating the underlying health condition. But certain skin conditions, such as psoriasis, Sweet’s syndrome, and pyoderma gangrenosum, may require additional treatment.

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