Ulcerative colitis and some of the medications used to treat it may cause skin issues for some, including rashes, psoriasis, and acne.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that affects the large intestine, but it can also cause skin issues. These can include painful rashes.

Some rashes are the result of inflammation within your body. Other skin issues linked to UC may be caused by medication used to treat the condition.

Pictures of UC skin rashes

Erythema nodosum is the most common skin issue for people with IBD. Erythema nodosum are tender red nodules that usually appear on the skin of your legs or arms. The nodules may also look like a bruise on your skin.

This condition tends to coincide with flare-ups, sometimes occurring just before a flare starts. Once your UC is under control again, the erythema nodosum will likely go away.

Pyoderma gangrenosum starts as a cluster of small blisters that can spread and combine to create deep ulcers. It’s usually seen on your shins and ankles, but it may also appear on your arms. It can be very painful and cause scarring. The ulcers could become infected if they’re not kept clean.

Pyoderma gangrenosum is thought to be caused by immune system disorders, which may also contribute to UC. Treatment involves high doses of corticosteroids and drugs that suppress your immune system. If the wounds are severe, your doctor may also prescribe pain medication for you to take.

Sweet syndrome is a rare skin condition characterized by painful skin lesions. These lesions start as small, tender red or purple bumps that spread into painful clusters. They’re usually found on your face, neck, or upper limbs. Sweet’s syndrome is linked to active flare-ups of UC.

Sweet’s syndrome is often treated with corticosteroids in either pill or injection form. The lesions may go away on their own, but recurrence is common, and they can result in scars.

Bowel-associated dermatosis-arthritis syndrome (BADAS) is also known as bowel bypass syndrome or blind loop syndrome. People with the following are at risk:

  • a recent intestinal
    surgery
  • diverticulitis
  • appendicitis
  • IBD

Doctors think that it may be caused by overgrown bacteria, leading to inflammation.

BADAS causes small red spots that may form into bumps or pustules over the course of one to two days. These lesions are usually found on your upper chest and arms. It can also cause lesions that look like bruises on your legs, similar to erythema nodosum.

The lesions usually go away on their own but may come back if your UC flares up again. Treatment may include corticosteroids and antibiotics.

Psoriasis, an immune disorder, is also associated with IBD.

Psoriasis results in a buildup of skin cells that form white or silver-looking scales in raised, red patches of skin. Treatment may include topical corticosteroids or retinoids, systemic medications, immunotherapy, and light therapy..

In people with vitiligo, the cells responsible for producing the pigment of the skin are destroyed, leading to white patches of skin. These white patches of skin can develop anywhere on the body.

Vitiligo is often considered a type of autoimmune condition. Treatment can include topical corticosteroids or a combination pill and light treatment known as psoralen and ultraviolet A (PUVA) therapy.

Pyodermatitis vegetans is a rash with red pustules that can rupture and form raised scaly patches of skin known as plaques. It’s usually found in the skin folds of your armpit or groin. It’s linked to a similar skin condition known as pyostomatitis vegetans, in which pustules form in your mouth. The two conditions are collectively known as pyodermatitis-pyostomatitis vegetans (PPV).

PPV is so closely linked to UC that some people are only diagnosed with UC after one or both forms of PPV develop. The pustules usually appear after UC has been active for several years.

Leukocytoclastic vasculitis is also known as hypersensitivity vasculitis. In leukocytoclastic vasculitis, inflammation causes small blood vessels to burst and blood to pool under your skin. This leads to purple-colored spots known as purpura. The spots can be small or large patches and are usually found on your ankles or legs.

In most cases of leukocytoclastic vasculitis, the skin lesions go away once the underlying UC is treated.

Ulcerative colitis is also linked to cystic acne in some people. Cystic acne is a painful type of acne that develops under your skin. Cystic acne can be treated with topical prescriptions like retinol or benzoyl peroxide.

If you have cystic acne and either have UC or are at high risk of developing it, you shouldn’t use the prescription drug Accutane. Accutane has been linked to UC and other IBDs in those with an increased risk.

Hives are red and often itchy skin rashes that can appear on any part of your body. UC is linked to cases of chronic hives. They may occur as a reaction to medications you take to manage your UC.

If you start a new medication and experience persistent hives, contact your doctor about alternatives.

Several rashes and other skin conditions are linked to UC or the medications that treat it. Talk with a healthcare professional about any skin changes you notice. Depending on the type of skin issue, you may need oral or topical medication.