Classically, there is initially a colicky periumbilical pain which migrates to the right lower quadrant and becomes more severe. Diarrhea and loose stools are also common, often preceding the acute attack by hours to days. Leukocytosis typically follows. The order in which these signs and symptoms develop is fairly rigid and does not usually vary. Muscle guarding is common, but may be absent following perforation.
Rebound tenderness is a sign of peritonitis.
Rectal exam may show marked tenderness in the case of a low lying appendix. Positive psoas and obturator signs indicate inflammation adjacent to these muscles. Appendicitis is most common in late childhood and early 20's, but may occur in any age group. While more common in males in the teenage years, the sex incidence equalizes by the mid 30's. It is more common in Western nations as is diverticular disease, probably due to lower fiber intake allowing impaction of inspissated fecal material to occlude the appendiceal lumen.