Eosinophilic Ascites: An Underrecognized Entity in Peritoneal Disorders

Background Eosinophilic ascites (EA) is a rare, under-recognized condition characterized by eosinophil-rich peritoneal fluid, most frequently associated with eosinophilic gastroenteritis (EGE). Its true prevalence is unclear, often misdiagnosed as malignancy, tuberculosis, or cirrhosis. EA typically presents between ages 30 and 50, with slight male predominance. Its clinical importance lies in a favorable response to corticosteroids and the potential for severe complications such as intestinal obstruction if untreated. Objective This review consolidates current knowledge on EA, focusing on its etiology, pathophysiology, diagnostic challenges, and treatment strategies, while highlighting key knowledge gaps. Methods A narrative review was conducted using PubMed, SpringerLink, and Web of Science (2000-2025). Search terms included "eosinophilic ascites," "eosinophilia," and "ascitic fluid." Included studies reported histopathologically confirmed EA with ascitic eosinophilia > 10%, imaging data, and treatment outcomes. Case reports lacking confirmatory paracentesis or biopsy were excluded. Data on demographics, clinical presentation, fluid analysis, imaging, etiology, treatment, and outcomes were extracted independently by two reviewers. Results EA pathogenesis involves IL-5-driven eosinophilic infiltration of the gastrointestinal serosa. Diagnostic features include exudative ascites (protein > 2.5 g/dL) with eosinophilic predominance (60-90%), peripheral eosinophilia (85%), and CT evidence of bowel wall thickening (72%). Corticosteroids (0.5-1 mg/kg/day) achieve remission in 80% within two weeks; anti-IL-5 agents may benefit refractory cases. Significant gaps include absent diagnostic biomarkers and unknown relapse rates. Conclusion EA demands heightened clinical suspicion in eosinophilic ascites. Future priorities include the development of non-invasive diagnostics, trials comparing biologics with steroids, and the exploration of genetic mutations in refractory disease.