How Crohn’s Disease Affects Your Skin

Managing Crohn’s disease doesn’t end with digestive issues. In fact, there’s a name for Crohn’s disease symptoms that don’t involve the digestive system at all: extraintestinal complications. Skin problems are one of the most common types, along with arthritis and bone density issues.

According to the Crohn’s & Colitis Foundation, skin disorders affect about 20 percent of people with inflammatory bowel disease, a broad term that refers to both Crohn’s disease and ulcerative colitis. Some of these disorders, such as psoriasis, can get worse in winter, because freezing temperatures and dry indoor air can leave the skin parched. Moisturizing with ointments such as petroleum jelly (like Vaseline), using a humidifier, and avoiding coarse, potentially irritating fabrics can help combat this issue, says Amanda Moon, MD, a pediatric dermatologist at Children’s Hospital of Philadelphia.

Additionally, because Crohn’s — and many of the medications that treat it — can weaken the immune system, people with the disease may also be more susceptible to skin infections, says Dr. Moon. “Sometimes, a bacterial infection could be making psoriasis or other rashes worse,” she says. A dermatologist can prescribe medication to treat the infection.

Common Crohn’s-Related Skin Conditions

Below is a list of the most common skin problems that arise in people with Crohn’s.

• Erythema nodosum: “Erythema nodosum causes tender pink or red bumps to form under the skin, usually on the shins,” says Laura Winterfield, MD, MPH, an associate professor of dermatology at the Medical University of South Carolina in Charleston. Although erythema nodosum is unpredictable, it may accompany a Crohn’s flare and then fade when those symptoms are back under control. Wearing compression stockings and elevating the legs can help manage erythema nodosum, which is more common in women and affects about 2 to 10 percent of people with Crohn’s, according to the Crohn’s & Colitis Foundation.
• Pyoderma gangrenosum: Red-to-purple pus-filled blisters that turn into skin ulcers are the symptoms of this condition. It’s more likely to occur in areas where skin has been damaged or irritated, which is called pathergy. “Although these ulcers look infected, they’re usually not, so antibiotics don’t help,” says Dr. Winterfield. Pyoderma gangrenosum isn’t preventable, but avoiding skin trauma may decrease the risk. Treatment may require high doses of steroids.
• Aphthous stomatitis: This skin condition causes small mouth ulcers, also called canker sores. They commonly occur in people with Crohn’s when intestinal symptoms flare up and then go away when those symptoms subside. They are painful, sensitive, and usually form between the gums and lower lip or on the tongue. A balanced Crohn’s diet and vitamin supplements may help prevent canker sores. Medicinal mouthwashes may also help alleviate symptoms.

Other Skin Problems Related to Crohn’s

Localized skin conditions in the area around the anus include skin tags and skin cracks called anal fissures. These result from the swelling and irritation caused by Crohn’s. You can best prevent and manage them with good hygiene, warm baths, and soothing ointments.

Rare skin problems associated with Crohn’s include:

Crohn’s Skin Conditions Caused by Medication

Beyond skin conditions that stem from the disease itself, some Crohn’s medications may lead to adverse skin reactions.

• Sulfasalazine, a drug used to block inflammation in Crohn’s, may cause an allergic skin rash, hives, or itching. “In most cases, this medication can be replaced with another that does not contain [sulfonamides],” says Winterfield.
• Steroids are an important medication used to block inflammation in Crohn’s. But, long-term steroid use can cause skin thinning and loss of skin color, as well as aggravate acne, according to Mayo Clinic.
• Anti-tumor necrosis factor (TNF) drugs, a type of biologic medication used for Crohn’s disease, may cause a skin rash at the injection site. “Psoriasis is another immune disease that may be linked with Crohn’s, and anti-TNF drugs may trigger psoriasis in some people,” notes Winterfield.

A review published in March 2021 in the European Journal of Gastroenterology & Hepatology found that many people with IBD who were treated with anti-TNF medication experienced skin problems — most commonly, psoriasis. Another review, published in March 2022 in Frontiers in Immunology, found that psoriasis was not uncommon in people who received anti-TNF treatment for IBD.

That said, some research has concluded the opposite — that anti-TNF doesn’t increase the risk of psoriasis. In a review published in July 2022 in the journal Medicine (Baltimore), researchers found that anti-TNF treatments did not lead to the development of psoriasis in people with IBD. In addition, a review published in June 2022 in the Internal Medicine Journal found that people with IBD who take anti-TNF medications might also develop eczema, which makes the skin itchy and red.

Dermatologists will often work closely with gastroenterologists to determine a therapy that treats Crohn’s but doesn’t exacerbate skin issues, Moon says.

“It is important to remember that many of these skin conditions occur in people who don’t have Crohn’s disease, and also that people with Crohn’s disease can have skin conditions that aren’t caused by Crohn’s,” says Winterfield.

Learning as much as you can about Crohn’s and working closely with your doctor to keep your Crohn’s under control is the best way to prevent complications. Always check in with your doctor if you develop any new symptoms, including ones that have nothing to do with digestive issues.

Additional reporting by Ashley Welch.