Rashes, painful lumps, and flushed skin can occur due to Crohn’s disease. Most Crohn’s rashes clear up as the symptoms of IBD ease, but during a flare, short-term remedies can provide relief.

Crohn’s disease is an inflammatory bowel disease (IBD). Any part of the digestive tract, from the mouth to the anus, can become inflamed and cause symptoms.

However, Crohn’s disease does not just affect the digestive tract. Many people with Crohn’s disease experience symptoms outside the intestines, and skin disorders are relatively common. As such, people with Crohn’s disease may develop skin rashes. The Crohn’s and Colitis Foundation reports that up to 20% of people with IBD experience rashes.

This article will explain the different types of rashes Crohn’s disease can cause. It will also explain the appearance and possible location for each one, alongside information on how to treat them.

The appearance of erythema nodosum often coincides with an IBD flare. It can also happen just before a flare, which may warn the person with Crohn’s disease of an upcoming flare-up.

Appearance and location

Erythema nodosum is a swelling under the skin that causes darker colored or red patches, particularly around the shins and ankles, but sometimes on the arms.

These patches may be around 1–6 centimeters (cm) in diameter. They may feel hot, hard, and painful to the touch.


While these bumps will usually clear up on their own within 3–8 weeks, home treatments can relieve the symptoms.

Taking Crohn’s medication as a doctor has prescribed may prevent flare-ups of erythema nodosum.

Raising the legs while resting to reduce the swelling and wrapping a cool, damp cloth around the area to reduce itching can help.

If the rash is severe, a doctor may prescribe corticosteroids, such as Prednisone.

Pyoderma gangrenosum can happen in people with IBD, but it is more common in people with ulcerative colitis than Crohn’s disease. It is also more common in females.

Appearance and location

Pyoderma gangrenosum usually appears around the ankles and shins. However, it can affect any part of the body.

Pyoderma gangrenosum may begin as small blisters. If the blisters join together, they form a deep ulcer. This can happen rapidly, so a person who believes they have pyoderma gangrenosum should seek medical treatment as soon as possible.


Pyoderma gangrenosum may heal as a person treats other Crohn’s symptoms. However, due to the possible rapid progression of the condition, a person should contact their doctor if they notice symptoms.

If the condition does not improve quickly, a doctor may prescribe antibiotics and steroid creams.

Aphthous stomatitis, or canker sores, can affect people with Crohn’s disease. It may arise due to malabsorption.

Appearance and location

Aphthous stomatitis appears as small, shallow mouth ulcers. They often appear on the sides or underside of the tongue or between the gums and lower lip. They may feel hard and hot to the touch.


People with aphthous stomatitis may find that using a saline or antiseptic mouthwash helps treat the condition. They can also try using a softer bristled toothbrush.

Mouth ulcers that are less than 1 cm in size may heal within 2 weeks. Larger mouth ulcers that are 2–3 cm in diameter can take up to a few months and may lead to scarring.

Doctors may prescribe anesthetic or antiseptic creams for more severe cases of aphthous stomatitis. Steroids or laser therapy can help severe, persistent cases.

Skin tags are common among people with Crohn’s disease. They appear as small flaps of skin that may form after a swelling. Friction due to skin tags may cause irritation that can resemble a rash.

Appearance and location

Extra skin can thicken and form a flap anywhere on the body. However, skin tags most often occur near the anus in people with Crohn’s disease.

If skin tags occur around the anal area, fecal matter can become trapped and irritate the skin.


Skin tags are harmless and do not require treatment unless they are causing a person significant discomfort.

Doctors may suggest avoiding surgical removal of perianal skin tags because they can damage or scar the anal sphincter.

Some less common rashes a person with Crohn’s disease may experience include:

  • Sweet’s syndrome: This syndrome causes sudden fever with red or darker colored skin patches, particularly on the upper body. The rash may be tender to the touch. Sweet’s syndrome is more common in females.
  • Acrodermatitis enteropathica: This flaky rash usually appears on the face, hands, and feet. It can happen due to a lack of zinc. People with Crohn’s disease may suffer vitamin and mineral deficiencies, as their digestive tract may not be able to absorb the required amounts. Doctors will stress the importance of nutrition to people with the disease and may suggest supplements.
  • Epidermolysis bullosa acquisita: This condition produces blisters around the feet, knees, elbows, and hands. People who have had Crohn’s disease for years may suddenly develop this rash.
  • Skin cancer: Rates of skin cancer tend to be higher among people with IBD who are taking immunosuppressant medicines than in the general population. It is important to use sunblock regularly and seek medical advice for any changes in the skin.

In many cases, skin rashes are a direct symptom of Crohn’s disease itself. This may be due to shared immune cells that cause both Crohn’s and skin conditions.

However, other causes and triggers of rashes in Crohn’s disease include:

  • Associated conditions: Conditions such as psoriasis or vitiligo may appear alongside Crohn’s disease and cause skin effects that can appear as a rash.
  • Medication reactions: Doctors may prescribe medications such as anti-TNF drugs to people with Crohn’s. This drug can cause rashes that resemble eczema or psoriasis.
  • Nutritional deficiencies: Crohn’s disease can lead to malabsorption, which can cause vitamin deficiencies. For example, a zinc deficiency may cause red sores and pustules.

Learn how to recognize a Crohn’s flare-up and what to do here.

Treatment for rashes will depend on their type and severity. Sometimes, treating Crohn’s disease itself can clear up rashes, too.

A doctor may recommend the following medical treatment:

  • taking corticosteroids or immunosuppressive drugs
  • taking antibiotics
  • taking vitamin supplements
  • discontinuing or changing doses of medication
  • undergoing surgery

Learn more about Crohn’s disease treatment here.

A Crohn’s flare can trigger rashes or skin disorders in as many as 1 in 5 cases.

However, a person may wish to contact a doctor if:

  • their skin symptoms cause discomfort or pain
  • rashes cover a large area of the body
  • rashes are spreading
  • they notice signs of infection, such as fever or pus

It is relatively common for a person to experience skin conditions, such as rashes, as a result of Crohn’s disease.

Most Crohn’s disease rashes clear up on their own as flare-ups go into remission or as a result of continuing Crohn’s treatment.

Anyone who feels concerned about a skin rash they have developed should contact their doctor.