Erythema nodosum are bumps that appear under the skin. They feel like painful, tender, warm nodules, 1 to 5 cm in diameter, with raised bluish-red lesions. They are usually found on the extremities of the body (your hands and feet). They do not form ulcers. They resemble bruises on the skin, but are not always visible. They are often accompanied by fever, chills, and joint pains.
They are the most common skin condition associated with IBD, affecting 3% to 10% of people with ulcerative colitis and 4% to 15% of those with Crohn’s disease.
Erythema nodosum tends to come and go with intestinal inflammation. It flares up when you are having a flare of IBD. Because of this, treatment of erythema nodosum usually involves treatment of the underlying IBD.
However, in the case where erythema nodosum is not associated with inflammation, other drugs that could be used include steroids, potassium iodide, colchichine, dapsone, and immunosuppressants.
Pyoderma gangrenosum is a skin condition that starts out as skin nodules and then spreads to form ulcers filled with pus. It is more severe and debilitating than erythema nodosum.
Pyoderma gangrenosum is the second most common skin condition that arises in patients with IBD. It affects 1% to 3% of people with IBD. Pyoderma gangrenosum flare-ups do not seem to be correlated with IBD inflammation.
This condition requires aggressive therapy from a dermatologist. Treatment includes a combination of medications, with options from the following:
Topical therapies
Topical medications can be applied directly to the skin and include antibiotics, steroids, benzoyl peroxide, sodium cromoglycate, hydrogen peroxide, 5-aminosalicylic acid, or tacrolimus.
Steroids
Various types of steroid treatments may be used to manage pyoderma. This includes tropical steroids, steroids injected into the lesions, and/or systemic steroid therapy such as high-dose oral prednisone until the lesions clear and then a low dose of prednisone afterwards.
Other medications
Other medications used to treat pyoderma include minocycline, sulfasalazine, azathioprine, dapsone, potassium iodide, immunoglobulin, mycophenolate mofetil, oxygen treatment and/or biologics.
Surgery
Surgery should be avoided but it can be considered if medications are not working.