Ulcerative colitis is an inflammatory bowel disease that affects around 700,000 people in the United States. The disease causes inflammation and ulcers in the digestive tract, as well as a variety of other symptoms throughout the body. People with ulcerative colitis are at risk of several skin complaints, including a condition called pyoderma gangrenosum. Find out how ulcerative colitis increases the risk of pyoderma gangrenosum, and learn more about the treatment you may need to have for the condition.

The link between ulcerative colitis and pyoderma gangrenosum

Doctors aren't sure what causes ulcerative colitis. Many experts believe that the condition occurs because of a problem with the body's immune system. For people with ulcerative colitis, an abnormal response in the immune system seems to turn the body on itself, causing the painful ulcers associated with the disease.

Similarly, doctors don't completely know what causes pyoderma gangrenosum, but scientists also believe the condition relates to abnormal immune system responses. About 50 percent of pyoderma gangrenosum cases occur in people with inflammatory bowel disease. In fact, the symptoms of pyoderma gangrenosum sometimes appear before a doctor diagnoses ulcerative colitis.

Symptoms

When pyoderma gangrenosum first appears, you may see small, reddish-purple bumps or blisters on the skin. These growths can eventually develop into painful open sores with a blue or violet border. The severity of the condition varies between patients. For some people, the sores will disappear without treatment. For other patients, the ulcers can spread, grow larger and deeper and become excruciatingly painful.

Doctors and dermatologists categorize the ulcers into four categories. These are:

• Classic pyoderma gangrenosum, which normally forms on the legs and creates deep, painful ulcers.
• Atypical/bullous pyoderma gangrenosum, where small, superficial blisters appear on the hands.
• Vegetative pyoderma gangrenosum, where the ulcers are chronic and painless.
• Pustular pyoderma gangrenosum, where painful bumps on the arms and legs develop into pus-filled ulcers.

To diagnose the condition, your doctor may refer you to a dermatologist. He or she will often carry out a biopsy to examine a sample of tissue.

Treatment

There are various treatment options for people with pyoderma gangrenosum. Some patients respond well to topical skin treatments. A topical corticosteroid with an occlusive (air and watertight) dressing can sometimes get rid of the ulcers.

More commonly, patients need a course of oral corticosteroids to bring the symptoms under control. Doctors will normally prescribe a high dose of prednisolone, which patients must quickly reduce to cut the risk of unwanted side effects on their bones. This treatment is particularly effective for a colitis patient experiencing a general flare-up of all his or her symptoms, as the drugs can ease all the side effects of colitis.

Immunosuppressive drugs can also help tackle the symptoms of pyoderma gangrenosum. Ciclosporin and azathioprine can both ease the symptoms of the condition, although some people with ulcerative colitis take these drugs on an ongoing basis anyway. Some doctors will prescribe an infusion of an anti-inflammatory drug called infliximab. Studies show that this drug can quickly control a severe outbreak of pyoderma gangrenosum.

In all cases, pyoderma gangrenosum can quickly escalate in severity. As such, dermatologists recommend that you seek treatment as soon as you notice the symptoms.

Outlook and complications

With prompt treatment, many ulcerative colitis patients recover quickly from pyoderma gangrenosum. You'll need to keep the wounds clean and sterile, and a nurse will regularly need to change your dressings to cut the risk of infection. In some cases, a doctor or nurse will need to gently remove damaged tissue. Unfortunately, scarring from pyoderma gangrenosum is relatively common.

Left untreated, pyoderma gangrenosum can increase the risk of more serious side effects. The disease can lead to a serious infection called sepsis, which can prove fatal, especially in older patients. Talk to your doctor or dermatologist for more advice about the condition.​