What is the hallmark symptom of ulcerative colitis?

The hallmark symptom of ulcerative colitis is bloody diarrhea. This condition is characterized by inflammation and ulceration of the colonic mucosa, which leads to the presence of blood in the stool. As the colonic lining becomes damaged, it fails to maintain its integrity, resulting in bleeding and consequent diarrhea. Patients typically experience frequent bowel movements, often accompanied by an urgency to defecate.

Blood in the stool can vary from being a small amount of bright red blood to more profuse hematochezia, which is indicative of more severe disease. This symptom is essential for diagnosing ulcerative colitis, as it distinguishes this condition from other gastrointestinal disorders. Other symptoms, while common in ulcerative colitis, such as abdominal cramping and weight loss, are not as specific and can be seen in various other gastrointestinal ailments. Therefore, bloody diarrhea stands out as the defining symptom of ulcerative colitis.