Background: Eosinophilic esophagitis (EoE) is an emerging clinicopathologic entity defined by abnormal esophageal eosinophilic infiltration. Our understanding of this disease is hampered by the lack of a uniform diagnostic standard. The aim of this systematic review was to determine the range of diagnostic strategies and histologic criteria in the EoE literature.
Methods: The MEDLINE-indexed literature from 1950 through December 31, 2006 was independently searched by two investigators. To identify additional relevant studies, bibliographies were hand searched, as were the published proceedings of the 2000-2006 American College of Gastroenterology and American Gastroenterological Association national meetings. Data were extracted from all human EoE case reports, case series, cross-sectional and cohort studies, and clinical trials.
Results: Of 318 publications initially identified, 116 original articles, 39 abstracts, and 69 reviews were included. We found 10 different histologic definitions of EoE, ranging from 5 to 30 eosinophils per high-powered field (hpf), though 41 (35%) of the original articles did not state their diagnostic criteria. In the 13 original articles (11%) reporting an hpf area, the eosinophil density per mm(2) varied 23-fold. There was also variation in esophageal biopsy protocols, but specific protocols were reported in just 45 (39%) original articles.
Conclusions: Significant variability in diagnostic criteria for eosinophilic esophagitis exists, and in a large proportion of studies, criteria are not reported. Because of this lack of a common disease definition, conclusions drawn from the cumulative EoE literature should be viewed with caution. A consensus research-quality standard for diagnosis of eosinophilic esophagitis is needed.