Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that causes inflammation and ulcers in the mucosa of the digestive tract. These ulcers usually begin in the rectum and spread to other parts of the large intestine (colon). The symptoms of UC typically begin between the ages of 15 and 30.^[1]

The most common symptom of UC is bloody diarrhea with or without mucus. People may also experience an increased urge to defecate, abdominal pain, weight loss, fever, anemia, and fatigue. Symptoms can wax and wane: people can experience periods free of symptoms (known as remission), followed by flare-ups (known as relapse).

To diagnose UC, a healthcare provider must rule out other conditions based on a physical exam, blood tests, and stool tests. A biopsy may be needed through a colonoscopy (a procedure that examines the entire large intestine) or sigmoidoscopy (a procedure that examines the lower part of the large intestine) to confirm a diagnosis.

There is no cure for UC, but receiving appropriate care from a gastroenterologist and medications can help manage symptoms. Medications containing 5-aminosalicylates (5-ASA) are the first-line treatment. If 5-ASA medications fail, immunosuppressants, including a multitude of newer antibody medications, or corticosteroids may be given.

In severe cases, surgically removing parts or all of the large intestine may be necessary. If the entire large intestine must be removed, most people prefer to have a restorative proctocolectomy ileal pouch-anal anastomosis (RPC-IPAA) procedure, which involves removing the rectum as well as the large intestine, and creating a pouch from the small intestine that attaches to the anus to allow normal defecation. If a person's anal sphincter function is poor, the small intestine may be routed outside the body, where stool is collected with a small pouch.^[2]

Vitamin D has been shown to reduce inflammatory biomarkers related to UC and improve intestinal barrier function when used as an adjunctive treatment to 5-ASA medications.^[3] Curcumin may also help achieve remission, but more robust studies are needed.^[4]

There is some evidence to support the use of probiotics, prebiotics, and synbiotics (a supplement containing both probiotics and prebiotics) in achieving remission and lowering inflammatory biomarkers related to UC.^[5][6]

Since people with IBD are susceptible to nutritional deficiencies, the European Society for Clinical Nutrition and Metabolism recommends supplementation with nutrients such as iron, vitamin D, and folic acid in those who are deficient.^[7]

There is no evidence that people with UC benefit from restrictive diets, and long-term use may result in nutritional deficiencies.^[8] Although some evidence suggests that the low-FODMAP diet can help reduce symptoms of IBD, it does not improve stool consistency or reduce mucosal inflammation.^[9]

There is emerging evidence that fecal microbiota transplants can help people with UC achieve remission.^[10] Helminth therapy — an experimental treatment that involves purposely infecting someone with a parasite — has also been investigated, but there is conflicting evidence regarding its efficacy.^[11] There is some research examining treatments commonly used in traditional Chinese medicine, like moxibustion and acupuncture, but the poor quality of these studies casts doubt on the positive findings.^[12][13]

The specific cause of UC is unknown. It does appear, however, that a dysfunction in the immune system causes immune cells and inflammatory molecules to damage the digestive tract. It is considered an autoimmune disease. Additionally, genetics, lifestyle, and the gut microbiome also play a role in the development of UC.^[2]