Which of the following is not a feature of irritable bowel syndrome

In irritable bowel syndrome the most common presentation is that of recurrent abdominal discomfo, usually colicky or cramping in nature, felt in the lower abdomen relieved by defecation. Abdominal bloating worsens throughout the day.The bowel habit is variable. Most patient alternate between episodes of diarrhea and constipation. Those with constipation tend to pass infrequent pellety stools. Reference : Davidson, 23rd Edition, page no : 825.