The causes of chronic appendicitis mainly include three aspects. First, the narrowing of the appendiceal lumen. Most cases of chronic appendicitis have a history of acute appendicitis attacks. Long-term recurrent chronic inflammation can lead to thickening of the appendiceal wall, narrowing of the appendiceal lumen, and weakened peristalsis of the appendix. Second, obstruction within the appendiceal lumen by fecaliths is also a common cause of chronic appendicitis. Third, enlarged lymph nodes in the abdominal cavity can compress the appendiceal lumen, causing narrowing and repeated bacterial infections in the appendix. These are the common causes of chronic appendicitis.