What should you know about erythema nodosum in ulcerative colitis?

Erythema nodosum usually appears as painful, warm lumps beneath the skin, commonly on the shins. The overlying skin may look red or bruised as the inflammation changes. It is an inflammatory reaction rather than an open wound, and the lumps often fade without scarring.

In people with [Ulcerative Colitis](/conditions/ulcerative-colitis/), erythema nodosum can occur when bowel inflammation is active, but skin symptoms and bowel symptoms do not always change together. A clinician also considers infection, medicines and other inflammatory conditions before confirming the explanation.

Arrange a review with your GP or inflammatory bowel team, especially if the lumps are new or your bowel symptoms have changed. Record their location, tenderness, onset and any fever, [Diarrhoea](/symptoms/diarrhoea/) or [Abdominal Pain](/symptoms/abdominal-pain/). Keep the legs supported, avoid rubbing the areas, and wear comfortable clothing.

Do not stop ulcerative-colitis medicine without advice. The clinician may focus on controlling bowel inflammation and choose symptom relief that fits your digestive health and other medicines. A [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) can help coordinate assessment.

Seek urgent help for severe or rapidly worsening abdominal pain, heavy rectal bleeding, repeated vomiting, inability to keep fluids down, faintness, confusion or marked weakness. These signs may reflect a serious bowel flare or dehydration rather than the skin reaction alone.

Get prompt advice for fever, spreading redness, pus, severe one-sided leg swelling, or painful eye symptoms. Tell the clinician if you take immune-suppressing treatment, because infection can need quicker evaluation.

Ask whether the lumps fit erythema nodosum, whether your ulcerative colitis appears active, and which pain relief is suitable. Ask how to monitor bowel symptoms, whether medicines could be contributing, and when follow-up or [Colorectal Cancer Screening](/treatments/diagnostics-and-screening/colorectal-cancer-screening/) is relevant to your care.