What are the initial symptoms of appendicitis? It is characterized by abdominal pain. The main symptom is abdominal pain that appears around the upper abdomen or navel, and some patients may also experience nausea and vomiting. Generally, two to three hours later, the abdominal pain gradually shifts to the lower right abdomen, which we clinically refer to as migratory right lower abdominal pain. This symptom accounts for about 80% of clinical cases, while some patients present directly with pain in the lower right abdomen, without transitional abdominal pain. Therefore, the primary symptom of appendicitis is abdominal pain, as described in these two scenarios. However, physical examination is also very important, typically revealing localized fixed tenderness in the lower right abdomen as the main clinical manifestation.