Gastrointestinal involvement is frequent in patients with systemic lupus erythematosus (SLE). Eosinophilic gastroenteritis, however, has only rarely been described in rheumatological conditions, despite its reported connection to autoimmune diseases, such as hypereosinophilic syndrome, vasculitides, and systemic mastoidosis. It presents typically with abdominal pain and diarrhea and is only exceptionally associated with ascites. Diagnosis can be problematic, as several other clinical conditions (malignancies, infection/tuberculosis, and inflammatory bowel diseases) have to be ruled out. It is basically a nonsurgical disease, with excellent recovery on conservative treatment. We report the rare case of a young woman with overlap syndrome who presented with abdominal pain and ascites. The diagnosis of eosinophilic enteritis was made based on clinical, radiological, and laboratory criteria. The patient was treated with corticosteroids with excellent response.