Under normal circumstances, acute appendicitis in adults is relatively well diagnosed and not easily misdiagnosed. Special types of appendicitis clinically include the following: 1) acute appendicitis in newborns, 2) combined appendicitis during pregnancy, 3) acute appendicitis in the elderly, and 4) appendicitis in patients with AIDS and HIV infection. Special types of appendicitis are relatively difficult to diagnose, and sometimes the complexity of the disease can easily lead to misdiagnosis and even delayed treatment, resulting in more serious consequences. In particular, appendicitis in newborns and pediatric patients may be imperfectly diagnosed due to their age, which can easily lead to septic appendix and even perforation, and sometimes serious complications such as infectious shock. Early diagnosis and early treatment of specific types of appendicitis is essential to avoid unnecessary complications and sequelae.