What Is Ulcerative Colitis, the Ailment Afflicting Shinzo Abe of Japan?

Ulcerative colitis, the gastrointestinal affliction that has debilitated Prime Minister Shinzo Abe of Japan so badly that he is resigning, is a chronic inflammatory bowel disease, which is suffered by millions and can flare up unpredictably.

It irritates and inflames the innermost lining of the large intestine and rectum, causing ulcers or sores. Symptoms can include uncontrolled diarrhea, rectal bleeding, weight loss, diminished appetite, abdominal pain and frequent need to use the bathroom.

The disease can strike at a young age and worsen over time, as appeared to happen to Mr. Abe, 65. Doctors say they have also seen it develop in people in their 50s and older who had not suffered symptoms at a young age.

Inflammatory bowel disease also includes Crohn’s disease, which can disrupt the entire gastrointestinal tract.

Ulcerative colitis and Crohn’s together afflict more than two million people in North America, more than three million in Europe and millions more worldwide, according to estimates in an article published in May by Clinical Gastroenterology and Hepatology, a medical journal.

Dr. Ashwin N. Ananthakrishnan, a gastroenterologist at Massachusetts General Hospital who was the lead author of that article, said ulcerative colitis was first seen