This article explores how skin conditions are related to ulcerative colitis (UC), which is a type of inflammatory bowel disease (IBD).
It also considers how to reduce skin problems during a flare-up and when to see a doctor.
Skin conditions associated with UC
There is a range of different skin conditions that are associated with UC. These are explored below.
1. Erythema nodosum
There are a number of different skin conditions associated with ulcerative colitis.
Erythema nodosum is the most common skin issue for people who also have UC. Up to 10 percent of people with UC may develop erythema nodosum.
Erythema nodosum causes tender red nodules to appear on a person's arms or legs. These nodules may look like bruises.
In people with UC, this skin rash tends to come up during a flare-up and go away when UC is in remission.
2. Pyoderma gangrenosum
According to this 2012 review, pyoderma gangrenosum is the second most common skin problem that may affect people with UC.
This skin rash begins as a cluster of blisters on the shins, ankles, or arms. It often spreads and can form deep ulcers. If not kept clean, this may become infected.
Researchers believe this condition is caused by a problem with the immune system that may be linked to the cause of UC.
Psoriasis is a skin condition caused by a problem with the immune system. It leads to red, patchy skin, covered with a build-up of dead skin cells.
Many people with UC and other types of IBD are also affected by psoriasis.
This 2015 study found that there were some genetic links between the genes that cause IBD and those that cause psoriasis. More research is needed to understand these connections fully.
Hives are red raised spots that may appear as a rash anywhere on the body. They form due to a reaction in the immune system.
Sometimes people react to the medication they are taking for UC, which can cause chronic hives.
6. Bowel-associated dermatosis-arthritis syndrome
Bowel-associated dermatosis-arthritis syndrome (BADAS) is a condition where small bumps form on the upper chest and arms, in addition to other symptoms. These bumps can then form pustules, causing discomfort. BADAS may also cause lesions on the legs.
Researchers do not fully understand the cause, but they think it may relate to inflammation as a result of bacteria in the gut. Having IBD makes it more likely a person will develop BADAS.
7. Pyodermatitis-pyostomatitis vegetans
Pyodermatitis vegetans and pyostomatitis vegetans are two skin conditions that are linked.
The former causes red pustules that burst and form scaly patches in the armpit or groin. The latter involves pustules in the mouth.
The two conditions are typically grouped together and called pyodermatitis-pyostomatitis vegetans (PPV).
This condition is associated with UC, though it is rare. Symptoms will typically occur after a person has had UC for a few years. Often, however, people are not diagnosed with UC until after a doctor has diagnosed PPV.
8. Sweet's syndrome
Sweet's syndrome is another condition that is linked to UC flare-ups.
When a person has Sweet's syndrome, small red or purple bumps on the skin develop into painful lesions. They often form on the upper limbs, face, and neck.
Vitiligo is a skin condition that destroys the pigment-producing cells in the skin. Vitiligo may lead to white patches forming anywhere on the body.
Researchers think that vitiligo is caused by an immune disorder. According to the National Institute of Health (NIH), around 20 percent of people with vitiligo also have another immune disorder, such as UC.
10. Leukocytoclastic vasculitis
Leukocytoclastic vasculitis (hypersensitivity vasculitis) occurs when small blood vessels under the skin become inflamed and die. The inflammatory reaction leads to the development of purple spots on the skin of the legs or ankles, called purpura.
The condition results from inflammation and is linked to UC flare-ups. Leukocytoclastic vasculitis typically goes away when UC is in remission
How are UC and skin rashes linked?
Extreme tiredness is one of the major symptoms of ulcerative colitis.
UC can be a painful and uncomfortable inflammatory condition that affects both the large intestine and the rectum.
When a person has UC, small ulcers develop in the lining of their colon. These can produce pus and bleed.
The main symptoms of UC are:
- ongoing problems with diarrhea
- blood, mucus, or pus in stools
- the need to pass stool often
- extreme tiredness
- loss of appetite
- weight loss
Ulcerative colitis flare-ups
Although UC is a long-term condition, a person with UC may go weeks or months without symptoms. This is called remission.
Periods of remission may be followed by flare-ups, where the person experiences many UC symptoms.
During a flare-up, a person with UC may experience symptoms in addition to those that affect the digestive system. These include:
- rashes or patches of red, swollen skin
- swollen or painful joints
- mouth ulcers
- red, irritated eyes
Why do skin rashes appear during flare-ups?
The inflammation in the body that causes UC can also affect the skin. This can lead to swollen and painful skin rashes.
According to a 2015 study, skin problems affect up to 15 percent of people with IBD, which includes people with UC.
The medication that a person might take to control their UC symptoms may also cause skin problems.
Reducing skin problems during a flare-up
People with UC often experience skin problems during flare-ups, so the best way to manage skin conditions related to UC is to manage UC itself.
A doctor can help a person with UC find the best methods for their symptoms and lifestyle.
When flare-ups occur, the following may help to reduce skin problems:
- taking corticosteroids to reduce inflammation
- eating a well-balanced diet to promote skin health
- keeping the affected skin clean to reduce infection risk
- covering the affected area with bandages
- taking over-the-counter pain relievers
When to see a doctor
Mouth ulcers are one of the non-digestive symptoms that may be experienced during a UC flare up.
If a skin complaint is particularly troublesome, it is a good idea to speak with a doctor to get a proper diagnosis and the right treatment.
If skin conditions are recurring or getting worse over time, it is a good idea to talk to a doctor about the best way manage them.
They can also help a person with UC find ways to manage their condition as a whole.