What is a connection between appendicitis and crohn's disease?

No connection: Crohn disease affects any part(s) of gastrointstinal tract, mouth to anus including appendix. The abdominal pain associated with crohn disease can be severe enough to simulate acute appendicitis.

Bowel inflammation: While crohn's disease can involve inflammation of the entire GI tract, appendicitis is confined to the appendix. Clinical presentation can be identical, as ileal inflammation (most common site for crohn's) & appendicitis both cause rlq pain. The treatment for appendicitis is surgery, while crohn's is treated with medical therapy (& surgery reserved for treating complications or medical failures.

Different: The cause of crohn's and appendicitis are extremely different. Appendicitis is localized non immune inflammation. Crohn's is more complex in nature and never cured.