Key Takeaways
- Clinical Bottom Line
- Standardizing the Endoscopic Description of EoE
- The Five Pillars of EREFS
- Clinical Implementation
Clinical Bottom Line
| EREFS Component | Endoscopic Finding | Scoring Criteria |
|---|---|---|
| E (Exudates) | White plaques / spots | 0 = Absent; 1 = Mild (<10% of surface area); 2 = Severe (>10% of surface area) |
| R (Rings) | Trachealization (corrugated rings) | 0 = Absent; 1 = Mild (subtle ridges); 2 = Moderate (distinct rings); 3 = Severe (stricture formation preventing passage of standard scope) |
| E (Edema) | Decreased vascular markings | 0 = Normal vasculature; 1 = Loss of vascular markings (pallor/edema) |
| F (Furrows) | Longitudinal lines/creases | 0 = Absent; 1 = Present |
| S (Stricture) | Focal luminal narrowing | 0 = Absent; 1 = Present (requires specifying diameter if measured) |
Standardizing the Endoscopic Description of EoE
Prior to the introduction of the Endoscopic Reference Score (EREFS) by Hirano et al. in 2013, the endoscopic description of Eosinophilic Esophagitis (EoE) was highly subjective. Terms like “feline esophagus” or “crepe-paper mucosa” were visually descriptive but lacked the quantitative rigor necessary for clinical trials or objective patient tracking.
As of 2026, the EREFS classification is universally utilized in both clinical research and daily gastrointestinal practice to grade the macroscopic severity of EoE, track treatment response, and stratify patients into inflammatory versus fibrostenotic phenotypes.
The Five Pillars of EREFS
The EREFS system evaluates five distinct macroscopic features, which broadly divide into inflammatory signs (Exudates, Edema, Furrows) and fibrostenotic/remodeling signs (Rings, Strictures).
1. Exudates (E)
Exudates are white plaques or spots adhering to the esophageal mucosa. These are clinically significant because they represent dense, superficial accumulations of eosinophils (eosinophilic microabscesses). They can easily be misdiagnosed as esophageal candidiasis; however, unlike candidiasis, EoE exudates do not typically wash away easily and are often smaller and more granular.
2. Rings (R)
Also known as “trachealization,” these are concentric, corrugated rings. They represent structural remodeling of the esophagus. Mild rings may flatten upon insufflation, while severe rings are fixed and substantially limit the lumen, often catching the endoscope as it is advanced.
3. Edema (E)
Edema is identified by the loss of the normal, fine submucosal vascular network. The esophagus appears pale, swollen, and featureless. This is a hallmark of acute mucosal inflammation.
4. Furrows (F)
Furrows are distinct longitudinal lines or creases running vertically down the esophagus. At biopsy, endoscopists specifically target these furrows or the adjacent mucosa, as eosinophil density is often highest in these regions.
5. Stricture (S)
A focal narrowing of the esophagus that may or may not allow passage of a standard diagnostic endoscope (typically 9-10 mm). Identifying a stricture immediately shifts the disease classification toward a primarily fibrostenotic phenotype, dramatically increasing the risk of food impaction and necessitating mechanical intervention (esophageal dilation) alongside medical therapy.
Clinical Implementation
While the EREFS score provides an excellent macroscopic summary, it is vital to remember that a normal-appearing esophagus (EREFS score of 0) occurs in 10-25% of adult EoE cases. Therefore, a pristine endoscopic appearance never precludes the necessity of obtaining multiple biopsies (typically 2-4 from the proximal/mid esophagus and 2-4 from the distal esophagus) if clinical symptoms of dysphagia are present.
Endoscopic guidelines summarized by the Gastroscholar Research Team. Last updated: April 16, 2026. This article is intended for gastroenterologists and endoscopy staff.
