About 20% of individuals with UC may have problems outside of the colon. These are called extraintestinal manifestations. The most common is joint pain or swelling. Specific rashes called erythema nodosum and pyoderma gangrenosum can occur though the latter is quite rare. Abnormalities in liver function are seen in 3% of subjects and can include primary sclerosing cholangitis and autoimmune hepatitis. Checking simple blood tests screens for liver disease. Other more ususual complications include eye inflammation and increased blood clotting leading to blood clots (deep vein thrombosis).