The peak incidence of acute appendicitis is in late childhood and adolescence. Clinical findings include generalized abdominal pain that later localizes to the right lower quadrant, fever, loss of appetite and nausea. CT findings may include an enlarged appendix >7 mm diameter; an appendicolith; a thick, enhancing appendiceal wall; deformity or thickening of the apex of the cecum and stranding in the adjacent mesenteric fat. Peritoneal fluid may also be seen.

In children, ultrasound for diagnosis avoids ionizing radiation that is more problematic than in adults. Many sites in the US lack the skill or interest in using ultrasound for the diagnosis of appendicitis.