A 32-year-old man with a 6-year history of ulcerative colitis presents with chronic diarrhea and abdominal pain. Colonoscopy shows continuous mucosal inflammation limited to the colon. Which of the following is the most common extraintestinal manifestation of ulcerative colitis in Indian patients?

Explanation

## Extraintestinal Manifestations of Ulcerative Colitis **Key Point:** Erythema nodosum is the most common extraintestinal manifestation (EIM) of ulcerative colitis, occurring in 2–4% of patients, followed by arthropathy and oral aphthous ulcers. ### Frequency of EIMs in UC | Manifestation | Frequency | Association with Disease Activity | |---|---|---| | Erythema nodosum | 2–4% (most common) | Active disease | | Arthropathy (peripheral) | 1–2% | Active disease | | Oral aphthous ulcers | 0.5–1% | Active disease | | Ankylosing spondylitis | 0.5–1% | HLA-B27; independent of disease activity | | Primary sclerosing cholangitis (PSC) | 0.5–1.5% | Independent of disease activity | | Pyoderma gangrenosum | 0.1–0.5% (rare) | Active disease | **High-Yield:** Erythema nodosum appears as painful nodules on the shins and is strongly linked to active intestinal inflammation. It regresses with disease remission. **Clinical Pearl:** Ankylosing spondylitis and PSC are HLA-B27–associated and occur independently of bowel disease activity, making them less predictable as markers of flare. **Mnemonic:** EIMs in IBD — **AAAA-PSC** - **A**rthropathy (peripheral) - **A**phthous ulcers (oral) - **A**nkylosing spondylitis - **A**cute erythema nodosum - **P**rimary sclerosing cholangitis - **S**kin (pyoderma gangrenosum) - **C**holelithiasis **Warning:** Do not confuse frequency with severity. PSC and ankylosing spondylitis are rarer but more serious and require independent monitoring.