Latest Nomenclature of Eosinophilic Disorders of the GI Tract
The current standard nomenclature for eosinophilic disorders of the gastrointestinal tract follows a two-tier framework that first identifies the specific location of involvement, followed by more granular characterization of disease involvement. 1
Primary Nomenclature Evolution
The nomenclature for eosinophilic disorders of the GI tract has evolved significantly over the past two decades:
Eosinophilic Esophagitis (EoE)
- Initially abbreviated as "EE" in 2007 2
- Changed to "EoE" in 2011 to avoid confusion with "erosive esophagitis" 2
- Current definition: a chronic, immune/antigen-mediated disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation 2
Non-Esophageal Eosinophilic Disorders
The current standardized nomenclature for non-esophageal involvement includes:
- Eosinophilic Gastritis (EoG): Stomach involvement only 3
- Eosinophilic Enteritis (EoN): Small bowel involvement only 3
- Eosinophilic Duodenitis (EoD): Specific duodenal involvement 3
- Eosinophilic Colitis (EoC): Colon involvement only 3
- Eosinophilic Gastroenteritis (EGE): Involvement of multiple GI segments 3, 4
Current Diagnostic Framework
The diagnostic criteria for eosinophilic disorders have also evolved:
- For EoE: ≥15 eosinophils per high-power field (or ~60 eosinophils per mm²) on esophageal biopsy, with symptoms of esophageal dysfunction, after comprehensive assessment of non-EoE disorders 2
- Important change: The 2018 guidelines removed the PPI trial requirement that was previously part of the diagnostic algorithm 2
Multi-Segment Involvement Terminology
For patients with involvement of multiple GI segments, there are two competing terminologies:
- "Non-EoE EGID and EoE"
- "Non-EoE EGID with esophageal involvement (EI)" 5
A survey of 91 experts showed that 61% preferred the term "non-EoE EGID with EI" since EoE is defined as isolated to the esophagus by current diagnostic criteria 5.
Differential Diagnosis Considerations
When diagnosing eosinophilic disorders, it's essential to rule out other causes of GI eosinophilia, including:
- Gastroesophageal reflux disease (GERD)
- Crohn's disease
- Connective tissue diseases
- Hypereosinophilic syndrome
- Infections
- Drug hypersensitivity reactions
- Achalasia
- Graft-versus-host disease
- Vasculitis
- Pemphigoid/pemphigus 2, 6
Clinical Implications
Understanding the correct nomenclature is crucial because:
- Disease burden and symptoms are generally higher in non-EoE EGIDs than in isolated EoE 5
- Treatment approaches may differ based on the specific segments involved
- Patients with EoE should be monitored for potential development of other EGIDs 7
The non-EoE EGIDs remain understudied and likely underdiagnosed, partly due to previous lack of clarity in terminology 1. The recent standardization of nomenclature represents an important step toward improved diagnosis, research, and treatment of these conditions.