Young children often have nonclassic presentations of appendicitis Pain and tenderness will vary based on exact location of the appendix Rapid improvement in pain in a child with high suspicion of appendicitis may occur at the time of perforation Diagnostic algorithms should incorporate a clinical risk score and ultrasound as the first-line imaging modality Current Evidence Acute appendicitis is the most common nontraumatic surgical emergency in children Anatomic characteristics may influence the incidence and presentation of appendicitis throughout childhood Lymphoid hyperplasia within the appendix is maximal in adolescence and might be related to the peak incidence in this age group Generally, obstruction of the appendix (by fecal material, an appendicolith, or simply lymphoid hyperplasia) is believed to be a key step in the development of appendicitis Once obstructed, bacterial overgrowth and invasion into the mucosal barrier lead to progressive inflammation and dilation Localized pain and tenderness develops Perforation rarely develops before 12 hours of pain but is common after 72 hours Perforation can lead to generalized peritonitis or focal abscesses Since younger children have a relatively underdeveloped omentum, they are much more likely to present with diffuse peritonitis Goals of Treatment Early recognition and treatment prior to perforation is ideal Ultrasound (US) should be used as the first-line imaging modality in stable patients, with advanced imaging reserved for children with nondiagnostic US and a persistent clinical concern for appendicitis Clinical outcomes for patients with suspected appendicitis include accurate identification of appendicitis over medical etiologies of focal abdominal tenderness, limiting the use of computed tomography among patients with uncomplicated acute appendicitis, minimizing the number of negative appendectomies, definitive treatment prior to perforation, and the consideration of serial examinations over advanced imaging for patients considered low risk for appendicitis Clinical Considerations Clinical Recognition The peak incidence of appendicitis in children occurs between and 12 years of age Although neonatal cases have been reported, appendicitis rarely occurs in