Acute eosinophilic appendicitis simulating uncomplicated appendicitis

Acute appendicitis is one of the most common abdominal emergencies worldwide. Uncomplicated appendicitis (UA), which does not involve perforation or peritonitis, has recently been treated with antibiotic therapy. Here, we report a case of acute eosinophilic appendicitis (AEA) that simulated UA and did not respond to antibiotic therapy. A 20-year-old Japanese woman emergently presented with the chief complaint of pain at the right iliac fossa. CT showed only swelling of the appendix. She was diagnosed with UA, and she received antibiotic therapy initially. However, the treatment was not effective and appendectomy was performed. The final histopathological diagnosis was AEA. The findings of this case suggest that AEA is likely to be diagnosed as UA. As AEA can simulate UA, the possibility of AEA should be considered when antibiotic therapy is not effective.